AC 90-117 - Data Communications

U

.S. Department

of Transportation

Federal Aviation

Administration Advisory

Circular

Subject: Data Link Communications Date: 10/3/17 AC No: 90-117

Initiated by: AFS-400 Change:

This advisory c ircular (AC) applies to all pilots, certificate holders, operators, and/or program

managers conducting data link communication operations and to those providing data

communication services on behalf of operators to meet Federal Aviation Administration (FAA) and International Civil Aviation Organization (ICAO) requirements.

The AC provides an overview of data link communication operations for U. S. domestic

operations and in oceanic and remote continental airspace. It includes operational use guidance,

minimum performance and services of communication service provider (CSP), performance monitoring, training requirements, and discrepancy reporting.

Michael Zenkovich

Deputy Executive D irector, Flight Standards Service

10/3/17 AC 90 -117

CONTENTS

Paragraph Page

Chapter 1. General ...................................................................................................................... 1-1

1.1 Purpose of this Advisory Circular (AC) ....................................................................... 1-1

1.2 Applicability .................................................................................................................. 1-1

1.3 Where You Can Find This AC ...................................................................................... 1-1

1.4 What This AC Cancels .................................................................................................. 1-1

1.5 Scope ............................................................................................................................. 1-2

1.6 AC Format ..................................................................................................................... 1-2

1.7 Version References ....................................................................................................... 1-2

1.8 FAA Document References .......................................................................................... 1-2

1.9 References (current editions) ........................................................................................ 1-2

1.10 Airworthiness .............................................................................................................. 1-5

1.11 Regulatory Basis for Data Link Communication ........................................................ 1-5

1.12 AC Feedback Form ..................................................................................................... 1-5

Chapter 2. Data Link Communication Overview ....................................................................... 2-1

2.1 Introduction ................................................................................................................... 2-1

2.2 What Are Data Link Communications? ........................................................................ 2-1

2.3 FANS ............................................................................................................................ 2-2

2.4 CPDLC and ADS -C ...................................................................................................... 2-2

2.5 ATN .............................................................................................................................. 2-4

2.6 B2 .................................................................................................................................. 2-4

2.7 FANS 1/A(+) and ATN ................................................................................................ 2-5

2.8 ACARS ATS ................................................................................................................. 2-5

2.9 Tower Data Link System (TDLS) ................................................................................. 2-5

2.10 CPDLC -DCL ............................................................................................................... 2-5

2.11 PDC ............................................................................................................................. 2-7

2.12 Data Authority ............................................................................................................. 2-9

2.13 ATS Us and Aircraft Interoperability ......................................................................... 2-10

2.14 Performance -Based Communication and Surveillance (PBCS) Concept ................. 2-17

2.15 RCP and RSP Specifications Supporting ATM Operations ...................................... 2-18

2.16 Required Surveillance Performance (RSP) ............................................................... 2-23

ii

10/3/17 AC 90 -117

2.17 High Frequency Data Link (HFDL) .......................................................................... 2-28

2.18 Future U.S. Domestic Airspace Data Link Communication Services ...................... 2-29

2.19 Data Communication Services Strategy .................................................................... 2-30

Chapter 3. Aircraft Eligibility ..................................................................................................... 3-1

3.1 Introduction ................................................................................................................... 3-1

3.2 Aircraft Eligibility ......................................................................................................... 3-1

3.3 Statement of Compliance (SOC) ................................................................................... 3-1

3.4 Configuration Control ................................................................................................... 3-3

3.5 Maintenance .................................................................................................................. 3-4

Chapter 4. Communication Service Providers (CSP) ................................................................. 4-1

4.1 CSP for Oceanic and Remote Continental Operations ................................................. 4-1

4.2 RCP 240 CSP Allocations ............................................................................................. 4-2

4.3 RCP 400 CSP Allocations ............................................................................................. 4-3

4.4 RSP Allocation Requirements ...................................................................................... 4-4

4.5 Alternate Means of Compliance ................................................................................... 4-5

4.6 CSP for U.S. Operations ............................................................................................... 4-5

4.7 CSP Monitoring ............................................................................................................ 4-8

Chapter 5. Operational Use Of Data Link Communications ...................................................... 5-1

5.1 Operational Use ............................................................................................................. 5-1

5.2 Data Link Operational Guidance .................................................................................. 5-2

5.3 Logon/Notification ........................................................................................................ 5-2

5.4 En Route ........................................................................................................................ 5-4

5.5 Voice Monitoring .......................................................................................................... 5-5

5.6 Free Text Messages ....................................................................................................... 5-6

5.7 Data Link Communication Failures .............................................................................. 5-6

5.8 ADS -C ........................................................................................................................... 5-6

5.9 Exiting CPDLC and ADS -C Areas ............................................................................... 5-7

5.10 Logoff/D isconnect ....................................................................................................... 5-7

Chapter 6. Performance Monitoring ........................................................................................... 6-1

6.1 Performance Monitoring ............................................................................................... 6-1

6.2 Oceanic and Remote Continental Airspace .................................................................. 6-1

iii

10/3/17 AC 90 -117

6.3 Performance Website .................................................................................................... 6-2

6.4 Substandard Performance ............................................................................................. 6-2

6.5 Corrective Aircraft Action ............................................................................................ 6-2

6.6 Data Link Performance Eligibility ................................................................................ 6-2

6.7 Procedures to Report Problems ..................................................................................... 6-2

6.8 Performance Monitoring in U.S. Domestic Airspace ................................................... 6-2

Chapter 7. Training ..................................................................................................................... 7-1

7.1 Training D ocumentation ............................................................................................... 7-1

7.2 Objectives ...................................................................................................................... 7-1

7.3 Ground and Flight Training .......................................................................................... 7-1

7.4 Pilot Knowledge Subject Areas .................................................................................... 7-2

7.5 Pilot Procedural Training Items .................................................................................... 7-3

7.6 Dispatcher Training ....................................................................................................... 7-4

7.7 Maintenance Training ................................................................................................... 7-5

Chapter 8. Reports ...................................................................................................................... 8-1

8.1 Introduction ................................................................................................................... 8-1

8.2 Common Reasons to Report ......................................................................................... 8-1

8.3 Oceanic and Remote Continental Problem Reporting .................................................. 8-1

8.4 U.S. Domestic Airspace Problem Reporting ................................................................ 8-1

8.5 Problem Reporting Process ........................................................................................... 8-1

Appendix A. Foreign Operators ................................................................................................. A-1

A.1 General ......................................................................................................................... A-1

A.2 Title 14 CFR Part 129 .................................................................................................. A-1

A.3 Application Process ..................................................................................................... A-1

A.4 Unique Address ............................................................................................................ A-1

A.5 U.S. Interoperability Requirements ............................................................................. A-1

A.6 Training ........................................................................................................................ A-2

A.7 Unsafe Per formance or Conditions .............................................................................. A-2

A.8 U.S. Domestic Airspace ............................................................................................... A-2

Appendix B. Data Link Communications Minimum Equipment List (MEL) and

Master Minimum Equipment List (MMEL) Provisions ........................................B -1

B.1 Inoperative Equipment ..................................................................................................B -1

iv

10/3/17 AC 90 -117

Appendi x C. Summary of Airspace Requirements .....................................................................C -1

C.1 Summary of Airspace Requirements ............................................................................C -1

Appendix D. Flight Planning ..................................................................................................... D-1

D.1 Filing Required Communication Performance (RCP)/Required Surveillance

Performance (RSP) Capabilities .................................................................................. D-1

D.2 Regulatory Basis .......................................................................................................... D-1

D.3 Example ....................................................................................................................... D-2

D.4 Item 10a Descriptors .................................................................................................... D-2

D.5 Item 10b Descriptors .................................................................................................... D-3

D.6 Item 18 RSP Specification ........................................................................................... D-3

D.7 Field 18/DAT for CPDLC or Pre -Departure Clearance (PDC) ................................... D-4

Appendix E. Voice Phraseology ................................................................................................. E-1

Appendix F. Controller -Pilot Data Link Communication (CPDLC) Uplink and

Downlink Tables .................................................................................................... F-1

Appendix G. Terminology and Acronyms ................................................................................. G-1

G.1 Terminology ................................................................................................................. G-1

G.2 Acronyms ..................................................................................................................... G-5

v

10/3/17 AC 90 -117

List of Figures

Figure 2 -1. Overview Data Link System ................................................................................... 2-1

Figure 2 -2. ADS -C Event Sequence .......................................................................................... 2-3

Figure 2 -3. Data Link Communication Services on Departure Procedure ................................ 2-6

Figure 2 -4. Next Data Authority Notification ......................................................................... 2-10

Figure 2 -5. Air Traffic Service Unit (ATSU) and Aircraft Interoperability

Designators ........................................................................................................... 2-11

Figure 2 -6. Performance -Based CNS/ATM Model ................................................................. 2-17

Figure 2 -7. Actual Communications Performance (ACP) ....................................................... 2-19

Figure 2 -8. RCP 240 Illustration ............................................................................................. 2-20

Figure 2 -9. RCP 400 Illustration ............................................................................................. 2-22

Figure 2 -10. RSP 180 Illustration .............................................................................................. 2-25

Figure 2 -11. RSP 400 Performance ........................................................................................... 2-27

Figure 2 -12. Data Communication Services Strategy ............................................................... 2-29

List of Tables

Table 2 -1. PDC vs. CPDLC -DCL ............................................................................................ 2-9

Table 2 -2. Interoperability Designators and Descriptions ...................................................... 2-12

Table 2 -3. Types of Data Link Systems and Operations ........................................................ 2-16

Table 2 -4. RCP 240 Transaction Time and Continuity Allocations —CPDLC ..................... 2-21

Table 2 -5. RCP 240 Availability Criteria (Aircraft System) .................................................. 2-21

Table 2 -6. RCP 240 Integrity Criteria (Aircraft System) ....................................................... 2-21

Table 2 -7. RCP 400 Transaction Time and Continuity Allocations —CPDLC ..................... 2-23

Table 2 -8. RCP 400 Avail ability Criteria (Aircraft System) .................................................. 2-23

Table 2 -9. RCP 400 Integrity Criteria (Aircraft System) ....................................................... 2-23

Table 2 -10. RSP 180 Surveillance Data Delivery and Continuity Allocations —ADS -C ........ 2-26

Table 2 -11. RSP 180 Availability Criteria (Aircraft System) .................................................. 2-26

Table 2- 12. RSP 180 Integrity Criteria (Aircraft System) ....................................................... 2-26

Table 2 -13. RSP 400 Surveillance Data Delivery and Continuity Allocations —ADS -C ........ 2-28

Table 2 -14. RSP 400 Availability Criteria (Aircraft System) .................................................. 2-28

Table 2 -15. RSP 400 Integrity Criteria (Aircraft System) ....................................................... 2-28

Table 4 -1. RCP 240 Transaction Time and Continuity Allocations to CSP ............................ 4-2

Table 4 -2. RCP 240 CSP Availability and Outages Pa rameters .............................................. 4-2

Table 4 -3. RCP 400 Transaction Time and Continuity to CSP Allocation .............................. 4-3

Table 4 -4. RCP 400 Availability and Outages Parameters ...................................................... 4-3

vi

10/3/17 AC 90 -117

Table 4 -5. RSP 180 Data Delivery Time and Continuity Criteria ........................................... 4-4

Table 4 -6. RSP 180 Availability and Outages Parameters ....................................................... 4-4

Table 4 -7. RSP 400 Data Delivery Time and Continuity Criteria ........................................... 4-5

Table 4 -8. RSP 400 Availability and Outages Parameters ....................................................... 4-5

Table 4 -9. Data Communications Network Services (DCNS) Performance Baseline ............. 4-7

Table 5 -1. CPDLC Connection Failure Responses .................................................................. 5-5

Table B -1. Minimum Equipment Lis t Example ....................................................................... B-1

Table B -2. Example of a Data Link Communication MMEL Provision ................................. B-2

Table C -1. Summary of Airspace Requirements ..................................................................... C-1

Table C -2. Subnetwork Designators ........................................................................................ C-3

Table C -3. Preferred Original Equipment Manufacturer Annotat ion ...................................... C-3

Table D -1. Item 10a Flight Plan COM Descriptors ................................................................. D-3

Table D -2. Item 10b Flight Plan Descriptors for Surveillance Equipment .............................. D-3

Table D -3. Voice, PDC, DCL .................................................................................................. D-4

Table D -4. DCL and En Route Data Link Clearances ............................................................. D-6

Table D -5. PDC Only and En Route Data Link ....................................................................... D-7

Table D -6. En Route Data Link Clearances Only .................................................................... D-7

Table E -1. Voice Phraseology Related to Controller -Pilot Data Link Communication

(CPDLC) From Pilot ............................................................................................... E-1

Table E -2. Voice Phraseology Related to CPDLC From the ATSU ........................................ E-2

Table F -1. Color Key ................................................................................................................ F-1

Table F -2. Response Attribute of CPDLC Message Element for Uplink Messages ................ F-1

Table F -3. Response Attribute of CPDLC Message Element for Downlink Messages ........... F-2

Table F -4. Route Uplink Message Elements (RTEU) .............................................................. F-3

Table F -5. Route Downlink Me ssage Elements (RTED) ......................................................... F-7

Table F -6. Lateral Uplink Message Elements (LATU) ............................................................ F-8

Table F -7. Lateral Downlink Message Elements (LATD) ..................................................... F-11

Table F -8. Level Uplink Message Elements (LVLU) ............................................................ F-13

Table F -9. Level Downlink Message Elements (LVLD) ....................................................... F-20

Table F -10. Crossing Constraint Uplink Messages (CST U) .................................................... F-24

Table F -11. Speed Uplink Messages (SPDU) .......................................................................... F-28

Table F -12. Speed Downlink Messages (SPDD) ..................................................................... F-31

Table F -13. Air Traffic Advisory Uplink Messages (ADVU) ................................................. F-32

Table F -14. Air Traffic Advisory Downlink Messages (ADVD) ............................................ F-36

Table F -15. Voice Communication Uplink Messages (COMU) .............................................. F-37

vii

10/3/17 AC 90 -117

Table F -16. Voice Communication Downlink Messages (COMD) ......................................... F-39

Table F -17. Spacing Uplink Messages (SPCU) ....................................................................... F-40

Table F -18. Spacing Downlink Messages (SPCD) .................................................................. F-42

Table F -19. Emergency/Urgency Uplink Messages (EMGU) ................................................. F-44

Table F -20. Emergency/Urgency Downlink Messages (EMGD) ............................................ F-45

Table F -21. Standard Response Uplink Message s (RSPU) ...................................................... F-46

Table F -22. Standard Response Downlink Messages (RSPD) ................................................. F-47

Table F -23. Supplemental Uplink Messages (SUPU) .............................................................. F-48

Table F -24. Supplemental Downlink Messages (SUPD) ......................................................... F-49

Table F-25. Free Text Uplink Messages (TXTU) .................................................................... F-49

Table F -26. Free Text Downlink Messages (TXTD) ............................................................... F-50

Table F -27. System Management Uplink Messages (SYSU) .................................................. F-51

Table F -28. System Management Downlink Messages (SYSD) ............................................. F-53

Table F -29. FANS 1/A Uplink Messages Not Recommended for Use .................................... F-54

Table F -30. FANS 1/A Downlink Messages Not Recommended for Use ............................... F-57

Table F -31. ATN B1 Uplink Messages Not Recommended for Use ....................................... F-58

Table F -32. ATN B1 Downlink Me ssages Not Recommended for Use .................................. F-58

viii

10/3/17 AC 90 -117

CHAPTER 1. GENERAL

1.1 Purpose of this Advisory Circular (AC) . This AC provides guidance for aircraft

eligibility and operational use of data link communications in the United States and in

oceanic and remote continental airspace. This document also provides explanations of

data link systems to inform those who may b e new to using digital aircraft

communication and surveillance systems. This AC provides new guidance associated

with updated and/or new operational authorization. The regulatory source basis for this AC is Title 14 of the Code of Federal Regulations (14 C FR) part 91, § 91.123

. For more

information, see paragraph 1.11.

1.1.1 AC Terms . The term “must” is used in this AC to indicate a mandatory requirement

driven by regulation or required for a system to operate pr operly. The term “should” is

used to indicate a recommendation. The term “operator” refers to the certificate holder, program manager, and operator/company. Future Air Navigation System (FANS) 1/A(+)

is used to denote both FANS 1/A and/or FANS 1/A+.

1.1.2 Altern ative Method of Compliance . In lieu of following the guidance in this AC without

deviation, operators may elect to follow an alternative method, provided the alternative method is found to be acceptable to the Federal Aviation Administration ( FAA ). This AC

does not change, add, or delete regulatory requirements or authorize deviations from regulatory requirements.

1.2 Applicability. This AC applies to operators under 14 CFR parts 91, 91 subpart K

(part 91K ), 121, 125, 129 , and 135 conducting data link communications operations in

the United States or in oceanic and remote continental airspace. This AC also applies

where the foreign authority has adopted International Civil Aviation Organization

(ICAO ) data link communication standards.

Note: Part 91 operators do not require operational authorization for the use of

data link in the United States . For data l ink operations in oceanic and remote

continental airspace and/or foreign countries requiring specific data link approval, part 91 operators may apply to their responsible Flight Standards office for a l etter

of authorization (LOA). Pilots using “J” codes f or U.S. domestic data link

en route require a data link authorization prior to entering oceanic and remote

continental airspace. P art 91 operators filing J codes for U.S. domestic data link

services must have a data link authorization to file J5 –J7 in oceanic and remote

continental airspace (s ee Appendix D

, Flight Planning).

1.3 Where You Can Find This AC. You can find this AC on the FAA ’s webs ite at

http://www.faa.gov/regulations_policies/advisory_circulars .

1.4 What This AC Cancel s. AC 120- 70C, Operational Authorization Process for Use of

Data Link Communication System, dated August 3, 2015, is cancelled.

10/3/17 AC 90 -117

1.5 Scope. The scope of this AC is limited to the interoperability designators listed in

Table 2- 2, Interoperability Designators and Descriptions. Aeronautical Information

Services (AIS) and Meteorological Information (METI) Services are excluded from the

scope of this AC.

1.6 AC Format. Chapter 2 , Data Link Communication Overview, is intended to inform those

not familiar with data link communications. Chapters 3 -8 provide aircraft eligibility and

operational guidance with the following topics:

• Chapter 3 , Aircraft Eligibility,

• Chapter 4 , Communication Service Provider s (CSP),

• Chapter 5 , Operational Use of Data Link Communications,

• Chapter 6 , Performance Monitoring,

• Chapter 7 , Training, and

• Chapter 8 , Reports.

1.7 Version References. The most current version of a document is designated by

parentheses “ ( )” placed at the end of the number designation. Specific versions are

indicated by a letter. If no letter appears after the document designation, then all versions

of the document are applicable . As a convenience, most references are hyperlinked to a

website containing the most current document . The most current ACs or Technical

Standard Orders ( TSO ) are available by clicking the following links :

1. ACs.

2. TSOs .

1.8 FAA Document References. This AC, along with AC 20 -140( ), provides all the

information necessary for data link communication compliance in the United States and

in oceanic and remote continental airspace and should be considered the “source documents” for the operational use of data link by U .S. ope rators and pilots. ICAO

documents are referenced in this document as a convenience to the operator.

1.9 References (current editions) .

1. Title 14 CFR Parts 21, 23, 25, 27, 29, 43, 91, 91K , 121, 125, 129, and 135

2. ACs:

• AC 20- 140, Guidelines for Design Approval of Aircraft Data Link

Communication Systems Supporting Air Traffic Services ( ATS).

• AC 20- 160, Onboard Recording of Controller Pilot Data Link Communication in

Crash Survivable Memory.

10/3/17 AC 90 -117

3. TSOs :

• TSO -C160a , Very High Frequency (VHF) Digital Link (VDL) Mode 2

Communications Equipment.

• TSO -C177 ( ), Data Link Recorder Equipment.

4. ICAO Documents :

• Annex 6 , Operation of Aircraft , Part I, International Commercial Air Transport.

• Annex 6 , Operation of Aircraft, Part II, International General Aviation .

• Annex 10 , Aeronautical Telecommunications, Volume II, Communication

Procedures including those with PANS status.

• Annex 10 , Aeronautical Telecommunications, Volume III, Communication

Systems , Part 1, Digital Data Communications Systems .

• Annex 11 , Air Traffic Services.

• Annex 15 , Aeronautical Information Services.

• Annex 19 , Safety Management.

• Document 4444 , Procedures for Air Navigation Services - Air Traffic

Managem ent.

• Document 7030 , Regional Supplementary Procedures.

• Document 8400 , Procedures for Air Navigation Services, ICAO Abbreviations

and Codes .

• Document 8585 , Designators for Aircraft Operating Agencies, Aeronautical

Authorities and Service s.

• Document 9694 , Manual of Air Traffic Services Data Link Applications .

• Document 9869 , Performance- Based C ommunication and S urveillance

(PBCS) Manual .

• Document 10037 , Global Operational Data Link (GOLD) Manual , ICAO Global

Guidelines for Data Link Operations.

• Document 10063 , Manual on Monitoring the Application of Performance -Based

Horizontal Separation Minima.

• North Atlantic Document 007 , North Atlantic Operations and Airspace Manual.

This document is published on behalf of the North Atlantic Systems Planning

Group by the European and North Atlantic Office of ICAO and includes data link material.

• North Atlantic Oceanic Errors Safety Bulletin (OESB) .

10/3/17 AC 90 -117

5. RTCA and European Organization for Civil Aviation Equipm ent

(EUROCAE ) Documents :

• DO-219, Minimum Operational Performa nce Standard (MOPS) for ATC

Two-Way Data Link Communications , dated August 27, 1993.

• DO-258A /ED-100A , Interoperability Requirements for ATS Applications Using

ARINC 622 Data Communications, dated April 7, 2005.

• DO-264/ED-78A, Guidelines for Approval of the Provision and Use of Air

Traffic Services Supported by D ata Communications, dated December 14, 2000.

• DO-280B Change 1 /ED-110B Change 1, Volume s 1 and 2, Interoperability

Requirements Standard for Aeronautical Telecommunication Network Baseline 1

(ATN B1 Interop Standards ), dat ed March 18, 2014.

• DO-290 Changes 1 and 2 /ED-120 Changes 1 and 2, Safety and Performance

Requirements Standard for Air Traffic Data Link Services in Continental

Airspace (Continental SPR Standard), dated April 29, 2004.

• DO-305A /ED-154A , Future Air Navigation System 1/A - Aeronautical

Telecommunication Network Interoperability Standard (FANS 1/A - ATN B1

Interop Standard) , dated March 21, 2012.

• DO-306 Change 1 /ED-122 Change 1, Safety and Performance Standard for

Air Traffic Data Link Services in Oceanic and Remote Airspace (Oceanic SPR

Standard), dated March 2011.

• DO-350A , Safety and Performance Requirements Standard for Baseline 2 ATS

Data Communications (Baseline 2 SPR Standard) , Volume s 1 and 2.

• ED-85A, DLASD for the Dep arture Clearance Data- Link Service .

• ED-89A, DLASD for the ATIS Data -link Service .

• ED-93, Minimum Aviation System Performance Standard for CNS/ATM

Message Recording Syst ems-Amendment 1, dated November 23, 1998.

• ED-106A , DLASD for the Oceanic Clearance Data- link Service .

6. Data Communications Network Service (DCNS) Alternative Media

Description . The DCNS Alternative Me dia Description define s the

qualification requirements for any media proposed to be used for domestic en route air traffic control (ATC) operations.

7. NAS Data Communicatio ns Guide . This document introduces operators to

data link communications operations within the U nited States National

Airspace. It discusses Controller -Pilot Data Link Communication –Departure

Clearance ( CPDLC -DCL ) and outlines the roles of the Airline Operations

Center, clearance delivery controllers, and pilots . The document describes the

general procedures for logging on /notifying , loading the flight plan, receiving

the CPDLC -DCL, responding to the CPDLC -DCL mess age, and

disconnecting /logging off. Examples of d ifferent types of revised

CPDLC -DCLs are provided with guidance for reviewing, processing ,

10/3/17 AC 90 -117

and responding to the clearances. Additionally, this guide provides general

information on the use of data link comm unications during en route

operations.

8. Data Link Communication Compliance Guide . This guide expedites

the compliance process as it condenses into one location the information

required for data link operations.

1.10 Airworthiness. For airworthiness guidance for new aircraft and systems, refer to

AC 20-140( ).

1.11 Regulatory Basis for Data Link Communication. CPDLC is an acceptable method of

delivering and accepting an ATC clearance i n accordance with part 91, § 91.123.

With data link communication technology, both digital and voice communication are

available to ATC and the pilot . Depending on the operation, data link communication

may be the most suitable method of communication as deemed necessary fo r ATC and

pilot purposes.

1.11.1 CPDLC Compliance and Voice Communication. CPDLC is not sufficient as a means

of compliance to the voice communication equipment requirements as per § § 91.129 ,

91.130, 91.131, 91.135, 91.205, and 91.511; part 121, §§ 121.99 and 121.122 ; and

part 135, § 135.165 , and is not required by these rules . For data link communications,

two-way radio voice communication or other means of communication approved by

the FAA must also be available .

1.11.2 Flight Plan Filing and Data Link Communication Capability . Pilots and operators must

file an accurate flight plan in accordance with §§ 91.169 and 91.153(a) (9). The Air

Traffic Service Unit ( ATSU) evaluates flight plan designator(s) to provide filed services.

Pilots and operators should use the guidanc e in this AC and other appropriate documents

to determine the data link communication de signator (s) for their route (s ee Appendix D).

1.11.3 Cockpit Voice Recorder (CVR) and Flight Data Recorder (FDR) . Operators must comply

with the CVR and FDR requirements of §§ 91.609(j) , 121.359(k) , and 135.151(h) , and

part 125, § 125.227(i) . FAA Information for Operators ( InFO) 16004 provides additional

guidance concerning the appli cability of these regulations.

1.12 AC Feedback Form. For your convenience, the AC Feedback Form is the last page of

this AC. Note any deficiencies found, clarifications needed, or suggested improvements

regarding the contents of this AC on the Feedback Form.

10/3/17 AC 90 -117

CHAPTER 2. DATA LINK COMMUNICATION OVERVIEW

2.1 Introduction. This chapter is intended to be informative for those not familiar with

data link communication. For those already knowledgeable, Chapters 3 through 8 of this AC are devoted to data link eligibility and use.

2.2 What Are Data Link Communications? “Data link” is a generic term encompass ing

different types of data link systems and subnetworks. Figure 2 -1, Overview Data Link

System, provides an overview of a data link system, including subnetworks. While many

data link capable aircraft have access to very high frequency ( VHF ) data link (VDL) ,

not all aircraft have access to additional satellite and/or high frequency ( HF) data link

capability. Similarly, not all communication service providers (CSP ) have HF data link

capability.

Figure 2 -1. Overview Data Link System

2.2.1 Aircraft Communication Addressing and Reporting System (ACARS) and Aeronautical

Telecommunications Network (ATN) . There are ACARS -based applications and

ATN-based applications. The VDL Digital Link Mode 2 subnetwork supports both

ACARS -based and ATN-based applications. The other subnetworks listed in this section

support ACARS-based applications only. Controller Pilot Data Link Communication (CPDLC) and Automatic Dependence Surveillance- Contract (ADS -C) can be Future

Air Navigation System ( FANS ) 1/A(+) or ATN -based. The FANS 1/A- based services

are used over the ACARS networks and the ATN-based services are used over the

10/3/17 AC 90 -117

ATN networks. The ACARS and ATN networks are not compatible. This AC

concentrates on CPDLC and ADS -C using FANS 1/A(+) unless specifically denoted

as ATN.

2.2.2 Data Link Subnetwork. Data link s ystems send messages over several communication

subnetworks:

• VDL Mode 0/A (i.e., ACARS) ,

• VDL Mode 2,

• Satellites, and/or

• High Frequency D ata Link (HFDL).

2.2.3 Data Link Systems . Data link communications is a means of transmitting and receiving

digital informa tion. ATS d ata link s ystems include the following:

• FANS 1/A(+),

• ATN Baseline 1 (B1) ,

• Baseline 2 (B2), and

• ACARS Air Traffic Service (ATS).

2.3 FANS. FANS 1/A is ACARS -based and provides direct data link communication

between the pilot and the air traffic contr oller via FANS 1/A avionics and FANS 1/A

ground end systems . In the early 1980s, International Civil Aviation Organization

(ICAO) began an effort to establish data link architecture under its FANS structure.

Boeing developed FANS 1 to DO- 219 and ARINC 745 using ARINC 622 binary

character data format followed by Airbus with its FANS A. These two systems are

referred to as FANS 1/A. The “ +” at the end of FANS 1/A indicates an updated system

version that includes a message latency monitor to detect old messages that may no longer apply. FANS messages can be sent over a variety of subnet works

depending on:

• Aircraft equipment,

• Configuration/media management, and

• Subnetwork availability .

2.4 CPDLC and ADS -C.

2.4.1 CPDLC . CPDLC is a means of communication between controller and pilot, using

data link for air traffic control ( ATC ) communications . Messa ges from an aircraft to the

Air Traffic Service Unit ( ATSU) may follow a standard format or may be free text.

Messages from a controller normally follow a stand ard format and usually require a

response from the pilot ( see Appendix F, Controller Pilot Data Link Communication

10/3/17 AC 90 -117

(CPDLC ) Uplink and Downlink Tables, for uplink message (UM) and downlink message

(DM) sets).

2.4.2 ADS -C. ADS -C is an automated surveillance information system that send s position and

other flight reports to the ATSU. After initial logo n/notification , a link is established

between the ground system and the aircraft . Without pilot input, the oceanic

ATSU/Aeronautical Operational Control ( AOC ) can establish a “contract ” with the

aircraft to receive reports of aircraft identification, aircraft position, altitude,

Mach number, vertical rate, true track, magnetic heading, ground speed, navigation

waypoints, and meteorological data.

2.4.2.1 ADS -C Contract Types. Depending on the aircraft type, there can be up to

five separate connections to different ground facilities (i.e., ATSU/AOC)

at any one time . Each connection can have one Periodic contract, one Event

contract, and one Demand contract.

1. Periodic. The ATSU can set or alter the update rate or time interval as needed (a higher update rate is usually required in high traffic

areas or associated with reduced separation).

2. Event. The aircraft system will communicate an event as established by the ATSU if there is a change in waypoint, vertical rate, lateral deviation or altitude. An event contract remains in effect until the ATSU cancels it or until the event(s) used to trigger the report occurs. The waypoint change event contract will trigger a report for all waypoint changes. All other eve nt contracts will

trigger a report on the first occurrence and then, if necessary, the

ATSU will need to request a new event contract indicating all desired event types. (See Figure 2 -2, ADS -C Event Sequence.)

3. Demand. The ATSU can request a single update as needed. This does not affect an existing contract preset rate.

Figure 2 -2. ADS -C Event Sequence

10/3/17 AC 90 -117

2.4.2.2 ADS -C Emergency. An ADS -C emergency can be triggered by the pilot

by the following means :

1. Manually, by selecting the ADS -C emergency function;

2. Indirectly, by triggering another type of emergency alerting system

(e.g., transmission of a CPDLC emergency message or selection of

a Secondary Surveillance Radar (SSR) emergency code); and

3. Covertly (The availability of that functionality may vary between aircraft ty pes).

Note: Once an ADS -C emergency has been triggered, under normal

circumstances, the avionics will continue to transmit ADS -C

emergency periodic reports until the pilot de-selects the ADS -C

emergency function.

2.5 ATN. ATN is a n inter -network architecture permitting ground, air -ground, and avionic s

data subnetworks to exchange digital data for the safety of air navigation and for the regular, efficient, and economic operation of ATS . ATN i s in limited use in Europe,

but not available in U.S. domestic airspace . The system is terrestrial based and

not available over oceanic and remote continental areas.

2.5.1 ATN B1 . ATN B1 consists of the following :

• Context management (CM) application for Data Link Initiation Capability (DLIC)

service; and

• CPDLC application for AT C Communication Management (ACM), AT C Clearance

(ACL) , and ATC Microphone C heck (AMC) services .

2.6 B2. B2 is ATN- based and will enable extended capabilities not possible with ATN B1

or FANS 1/A(+) as shown in Table 2- 2, Interoperabil ity Designators and Descriptions .

The FAA plans to implement the B2 CM , CPDLC, and ADS -C ATN- based applications

over the Internet Protocol Suite. B2 will provide additional services such as :

1. CPDLC:

• Initial F our-Dimensional ( 4-D) Trajectory Data Link (4DTRAD) ,

• Dynamic Required Navigation Performance (DRNP ), and

• Advanced flight I nterval Management (IM) .

2. ADS -C:

• Extended Projected Profile (EPP) information provided in ADS -C report s

supporting Information Exchange and Reporting ( IER), 4DTRAD, an d DRNP

services.

10/3/17 AC 90 -117

2.7 FANS 1/A(+) and ATN. Some avionics implementations support both the

FANS 1/A(+)- based applications and associated protocols and the ATN -based

applications and protocols. Depending on the system used by the ATSU, pilots may be

required to l ogoff/ disconnect any existing CPDLC or ADS -C session(s) and re establish

contact to another ground system when seamless transfer is not possible .

2.8 ACARS ATS. ACARS is a digital data link system for transmitting short, relatively

simple messages between aircraft and ground stations via VHF, HF, or satellite.

Note: The ACAR S network also carries FANS 1/A (+) messages .

2.8.1 Background. ARINC designed the ACARS protocol to replace VHF voice service

in 1978. Later, Société International de Télécommunications Aeronautique s (SITA )

added additional radio stations to augment this servic e. Airlines introduced ACARS

in the late 1980s to reduce crew workload and improve data integrity. Although the term

ACARS is often thought to encompass only a single data link syste m installed on the

aircraft, it actually refers to a complete air and ground system.

2.8.2 Aircraft and Ground ACARS Systems . The aircraft portion of ACARS system consists of

an avionics computer called an ACARS management unit (MU) and a control display

unit (CDU). On the ground, the ACARS system is made up of a network of radio

transceivers to receive (or transmit) data link messages and route them to various airlines

on the network.

2.8.3 ACARS ATS S upported A pplications Include :

• Departure Clearance ( DCL ) (not to be confused w ith CPDLC -DCL),

• Oceanic clearance (OCL),

• Terminal Weather Information for P ilots (TWIP) , and

• Digital Automatic Terminal I nformation Service ( D-ATIS ).

2.9 Tower Data Link System (TDLS). The TDLS automates tower -generated information

for transmission to aircraft via data link communication for both CPDLC -DCL and

Pre-Departure Clearance (PDC). The TDLS interfaces with sources of local weather data

and flight data in order to provide pilots with PDC, D -ATIS, and CPDLC -DCL services .

Note: The term PDC refers to the U.S. ATS of DCL. The DCL includes flight

plan route, climb via, and/or initial/requested altitude, beacon code assignment, and departure frequency.

2.10 CPDLC- DCL. CPDLC -DCL is available at va rious airports in U.S. domestic airspace

using FANS 1/A(+) via VDL Mode 0/A and/or Mode 2 for departure clearance services .

2.10.1 Dispatch or Flight Following Systems . For operators with a dispatch center,

flight following system, or other bas e of operations, copies of all data link

10/3/17 AC 90 -117

communications may be routed to, and stored by, the operator. Contact the FAA Data

Communications Program Office (refer to their website ) to coordinate.

2.10.2 CPDLC –Departure Clearance Service (CPDLC -DCL) . CPDLC -DCL provides a means

for requesting and delivering initial and revised DCLs . These CPDLC messages include

departure procedure, flight plan route, initial and requested altitude, beacon code,

departure frequency , and other non-route information .

Note 1: CPDLC -DCL is different than international DCL operations.

International systems use the ACARS ATS DCL application via

ARINC 623/European Organization for Civil Aviation Equipment ( EUROCAE )

ED-85A, not the FANS CPDLC application .

Note 2: At participating airports, PDC service s may be available for

non-FANS equipped aircraft.

2.10.3 CPDLC Specified on the Airport Diagram. To differentiate what communication services

are available at each facility, refer to the airport diagram, Standard Instrument Departures (SID), and other terminal procedures pages. See Figure 2 -3, Data Link Communication

Services on Departure Procedure, for the CPDLC annotation on a departure procedure.

Figure 2 -3. Data Link Communication Services on Departure Procedure

10/3/17 AC 90 -117

2.10.3.1 CPDLC -DCL l ogon/n otification (see paragraph 5.3). “KUSA” is the National

Single Data Authority (NSDA) for all CPDLC logons /notifications in the

United States . Pilots activate the data link communication system anytime

during preflight by logging on to/notifying KUSA with ATC . Within

30 minutes of the proposed departure time, an “ATC Connection Established”

message will be received if the following conditio ns are met:

1. Logon /notification information was correctly formatted ;

2. An ATC -filed flight plan is on file ;

3. Flight plan indicates the aircraft is CPDLC -DCL capable; and

4. ATC controller has approved the DCL .

2.10.3.2 Once a successful ATC connection has been established and the CPDLC -DCL

has been approved by the controller, the CPDLC -DCL will be automatically

sent to the aircraft. Pilots do not have to request a clearance. After the

clearance is received and verified, p ilots should:

1. Review the clearance and verify that no clarification from ATC is

required (Reject/Unable) ;

2. Confirm the appropriate runway , if assigned , departure procedure ,

and transiti on with no discontinuities ; and then

3. Acknowledge ( ROGER (DM3)/WILCO (DM0 ) or UNABLE

(DM1)) the message.

Note 1: If it becomes necessary to revert to voice after receiving

a clearance, pilots should respond with Reject/Unable to the uplinked

clearance.

Note 2: For CPDLC -DCL ground operations only, pilots can expect

an automated ATC -initiated logoff/disconnect 5 to 10 minutes after

takeoff.

2.10.3.3 If changes in tower or en route conditions occur (e.g. weather) the ATSU may amend the clearance information and transmit a revised CPDLC -DCL. Pilots

should follow the same procedure for revised clearances.

2.11 PDC. PDC is a subscriber based service to provide an effective and efficient means of

delivering a text -based electronic departure clearance prior to taxi. Data link

communication technologies are utilized via a PDC in which ATC clearances are sent to

a subscriber’s dispatch center, flight f ollowers , or base of operations . The clearance is

made available to the pilot with the following formats :

1. Internet access,

2. Airline gate terminal,

10/3/17 AC 90 -117

3. Airline operations area terminal,

4. Fixed -Base Operator ( FBO ) terminal, and

5. ACARS.

2.11.1 PDC Communication . It is not necessary for an aircraft to be equipped with data link

communication avionics for a flight to participate in the PDC service. It is only necessary

for the pilot to be able to obtain a printed or electronically displayed copy of the PDC

message prior to taxi (may be printed at the FBO terminal, the airline gate, etc.) .

The contents of the PDC message are relayed to the aircrew without modification,

omission, or alteration. PDC is at the discretion of the clearance deliver y controller. If the

controller determines that issuing a PDC could introduce confusion, the controller will

issue a verbal clearance to the aircrew. If the pilot is uncertain of the clearance, the PDC

must not be used and the pilot must contact clearance delivery via voice (telephone or radio) and obtain their clearance.

2.11.2 PDC vs. CPDLC -DCL . The primary difference between the PDC and CPDLC -DCL

services is the PDC service depends on the operator or other third party to deliver the

PDC to the aircraft whereas CPDLC -DCL service is a direct connection after

logon/notification from the tower automation to t he flight deck avionics of

FANS -equipped ai rcraft. See Table 2-1, PDC vs. CPCLC -DCL, below for a side -by-side

comparison.

10/3/17 AC 90 -117

Table 2 -1. PDC vs. CPDLC- DCL

PDC CPDLC -DCL

No Logon /Notification Required Logon /Notification Required

Sent to AOC or other Operator prescribed location Automatically sent directly to FANS 1/A(+) equipped

aircraft over data link communication equipment after

crew logon /notification

Delivered to the pilot by various means (i.e., over

ACARS, to the FBO terminal, to the airline gate ) Delivered over data lin k communication directly to

the aircraft within 30 minutes of proposed ETD

Depending on the delivery method, may require a

printed copy to be delivered to the aircraft Never requires a pa per copy to be delivered to

the aircraft

Does not require data link communication equipment to

be installed in the aircraft Requires data li nk communication systems on

the aircraft

Does not support revised clearances. Revisions must be

transmitted via voice frequency Revised clearances can be delivered directly to the

aircraft when necessary without restrictions

A specific call sign can only be used once in an

adaptable time period of 12– 18 hours at a specific

airport Only one call sign for a given tail can be in use for

CPDLC- DCL clearances at any given time

Requires manual input by the pilot or may be uploade d

from an AOC Clearance can be sent to the avionics system which may

enabl e “push to load” via a load prompt

2.12 Data Authority. “KUSA” is the national data authority for all U.S. domestic CPDLC

logons /notifications . Figure 2-12, Data Communication Services Strategy, describes the

current and planned data communication services to be available in the domestic en route

environment. CPDLC en route operations in U.S. domestic airspace will use

FANS 1/A(+) equipped aircraft with multi- frequency VD L Mode 2 radios. For an

alternate subnetwork, see paragraph 4.6.2 .

2.12.1 Current Data Authority (CDA) . When an aircraft system accepts a CPDLC connection,

this active connection initiates the exchange of messages between the ATSU and the

aircraft as the ATSU becomes the CDA. The CDA typically initiates address forwarding

to permit a downstream or adjacent ATSU (next data authority ( NDA) ) to establish an

inactive CPDLC connection and/or an Automatic Dependent Surveillance ( ADS ) contract

for monitoring purposes.

2.12.2 Data Authority Transfer . When the active CPDLC connection i s terminated, the aircraft

will activate any inactive connection. In this case, the next data authority becomes the

CDA and is now able to exchange CPDLC messages with the aircraft. Figure 2-4,

Next Data Authority Notification, illustrates the transfer from the CDA to the NDA.

10/3/17 AC 90 -117

Figure 2 -4. Next Data Authority Notification

ATSUs and Aircraft Interoperability. Figure 2-5, Air Traffic Service Unit (ATSU) and

Aircraft Interoperability Designators, shows different ATSU ground systems and

interoperable aircraft systems. The diagram shows the CSP and its Centralized ADS -C

System (CADS). CSP’s CADS enables an ATSU without FANS 1/A capability to receive

ADS -C reports from any FANS 1/A, FANS 1/A(+ ) or FANS 1/A ADS -C aircraft.

A designator is assigned to each type of ATSU and aircraft data link system. Explanations of each interoperability designator are provided below in Table

Table 2-3, Types of Data Link Systems and Operations, provides an overview of the

operational capabilities that are supported by each of the different data link systems.

10/3/17 AC 90 -117

Figure 2 -5. Air Traffic Service Unit (ATS U) and Aircraft Interoperab ility Designators

10/3/17 AC 90 -117

Table 2 -2. Interoperability Designators and Descriptions

Interoperability Designator Description

ACARS ATS ATS applications, DCL, OCL, TWIP , and D-ATIS supported

by ACARS.

Note: The term DCL used internationally is similar to the term PDC

used in the United States.

ATSU CADS CSP’s CADS enables an ATSU without FANS 1/A capability to

receive ADS -C reports from an y FANS 1/A, FANS 1/A(+) or

FANS 1/A ADS -C aircraft.

FANS 1/A Initial FANS 1/A ATSU applications, ATSU Facilities Notifications

(AFN), CPDLC , and ADS -C supported by FANS 1/A.

Note: FANS 1/A typically involves communication (CPDLC),

navigation ( Area N avigation (RNAV) /Required N avigat ion

Performance ( RNP )) and surveillance (ADS -C). This document refers

to the FANS 1/A for the data link system, which includes the CPDLC

and ADS -C applications. Refer to ICAO Doc 9613 for guidance

material on navigation (RNAV/RNP) qualification an d use.

FANS 1/A ADS -C ATSU applications AFN and AD S-C supported by FANS 1/A.

FANS 1/A ADS -C comply with AFN and ADS -C applications,

but do not include CPDLC application.

FANS 1/A+ Same as FANS 1/A, except with additional features, such as the

message latency timer function, described in DO-258A /ED-100A.

Note 1: FANS 1/A(+) aircraft is interoperable with FANS 1/A and

FANS 1/A(+) ground stations. However, message latency capabil ity is

only available when FANS 1/A(+) ground stations interoperates with

FANS 1/A(+) aircraft.

Note 2: Seamless transition of ATSU data link service occurs between

ATN B1 and FANS 1/A(+) ground stations when:

• Aircraft equipped with ATN B1 and FANS 1/A(+) data link system

also incorporates interoperability requirement IR -207, IR -209,

IR-210, IR -211, IR -212, IR -214, and IR -215 of

DO-305A /ED-154A.

• ATN B1 ground station incorporates interoperability requirement IRec -1 and IR -213 of DO -305A/ED -154A.

• FANS 1/A(+) ground station incorporates interoperability requirement IR -208 of DO -305A/ED -154A.

Otherwise, the pilot will lose their data link service requiring the pilot

to manually perform a logon/notification to reestablish ATSU data link

service.

10/3/17 AC 90 -117

Interoperability Designator Description

Note 3: Seamless transition of ATSU data link service occurs between

B2 and FANS 1/A(+) ground stations when:

• Aircraft equipped with B2 and FANS 1/A(+) data link system also

incorporates i nteroperability requirement NIR -153, NIR -155,

NIR-156, NIR -157, NIR -158, NIR -160, and NIR -161 of

DO-352A /ED-229A.

• B2 ground station incorporates interoperability requirement

NIRec -3 and NIR -159 of DO -352A/ED -230A.

• FANS 1/A(+) ground station incorporates interoperability

requirement NIR -154 of DO -352A/ED -229A.

Otherwise, the pilot will lose their data link service requiring the pilot

to manually perform a logon/notification to reestablish ATSU data link

service.

Note 4: To allow a FANS 1/A(+) data communication system on an

aircraft to communicate with an ATN B1 data communication s ystem

at an ATSU, the ATSU ground system needs to accommodate the FANS 1/A(+) aircraft by incorporating the interoperability

requirements of DO -305A/ED -154A.

Note 5: To allow a FANS 1/A(+) data communication system on an

aircraft to communicate with a B2 data communication system at an ATSU, the ATSU ground syste m needs to accommodate the

FANS 1/A(+) aircraft by incorporating the interop erability

requirements of DO -352A/ED -230A.

ATN B1 ATS applications CM and CPDLC supported by ATN B1:

a) CM is a data link application providing DLIC .

b) CPDLC (Version 1) for ACM, ACL, and AMC .

Note 1: Interoperability for DCL , downstream clearance (DSC),

D-ATIS, and flight plan consistency data link services, which are

defined in DO-280B /ED-110B are not supported.

Note 2: Seamless transition of ATS data link service between ATN B1

and FANS 1/A+ ground stations when:

• Aircraft equipped with ATN B1 and FANS 1/A+ data link system

also incorporates interoperability requirement IR -207, IR-209,

IR-210, IR -211, IR -212, IR -214, and IR-215 of

DO-305A/ED -154A.

• ATN B1 ground station incorporates interoperability requirement

IRec -1 and IR -213 of DO -305A/ED -154A.

• FANS 1/A+ ground station incorporates interoperability

requirement IR -208 of DO -305A/ED- 154A.

Otherwise, the pilot will lose their service requiring the pilot to

manually perform a logon/notification to reestablish ATS data link

service.

10/3/17 AC 90 -117

Interoperability Designator Description

Note 3: To allow a FANS 1/A+ data communication system on an

aircraft to communicate with a n ATN B1 data communication system

at an ATSU, the ATSU ground system needs to accommodate the

FANS 1/A+ aircraft by incorporating the inte roperability requirements

of DO- 305A/ED -154A.

Note 4: To allow an ATN B1 data communication system on an

aircraft to c ommunicate with a B2 data communication system at an

ATSU, the ATSU ground system needs to accommodate the ATN B1 aircraft by incorporating the inte roperability requirements of

DO-353A

/ED-231A.

Note 5: To allow a B2 data communication system on an aircraft to

communicate with an ATN B1 data communication system at an

ATSU, the B2 data communication system on the aircraft needs to

accommodate the ATN B1 ground system by incorporating the

interoperability r equirem ents of DO -353A/ED -231A.

B2 Version of the Baseline 2 Data Communication system described in

this section. The United States plans to use B2, as defined in

AC 20-140C, as part of FAA’s NextGen initiative. An aircraft

equipped with B2 is fully interoperable with any B2 ground station.

Aircraft equipped with a version of B2 other than that defined by

AC 20-140C are not eligible for the B2 interop designator. B2 is

comprised of the following data link applications and data link

services.

a) CM is a data link application supporting the follow ing data link

service: DLIC.

b) CPDLC (Version 3) is a data link application supporting the

following data link services: ACM, Clearance Request and Delivery

(CRD), AMC, DCL, Data Link Taxi (D- TAXI), Oceanic Clearance

Delivery (OC D), 4DTRAD, IER, In -Trail Procedure s (ITP), IM ,

and DRNP.

c) ADS -C (Version 2) is a data link application supporting the

following data link services : 4DTRAD, IER, Position Reporting (PR),

IM, and DRNP.

Note 1: To allow a FANS 1/A+ data communication system on an

aircraft to communicate with a B2 data communication system at an

ATSU, the ATSU ground syste m needs to accommodate the

FANS 1/A+ aircraft by incorporating the inte roperability requirements

of DO- 352A/ED -230A.

Note 2: To allow an ATN B1 data communication system on an

aircraft to communicate with a B2 data communication system at an

ATSU, the ATSU ground system needs to accommodate the ATN B1

aircraft by incorporating the inte roperability requirements of

DO-353A/ED -231A.

10/3/17 AC 90 -117

Interoperability Designator Description

Note 3: To allow a B2 data communication system on an aircraft to

communicate with an ATN B1 data communication system at an

ATSU, the B2 data communication system on the aircraft needs to

accommodate the ATN B1 ground system by incorporating the

interoperability requirements of DO -353A/ED -231A.

10/3/17 AC 90 -117

Table 2 -3. Types of Data Link Systems and Operations

Aircraft

Equipment and

Capability ACARS ATS

(ATSU Ground

Data Link System) CADS or

AOC

(ATSU Ground

Data Link System) FANS 1/A

(ATSU Ground

Data Link System) ATN B1

(ATSU Ground

Data Link System) FANS 1/A –

ATN B1

(ATSU Ground

Data Link System)

ACARS ATS ATC

communication

• DCL or PDC

• OCL Flight

information

• D-ATIS N/A N/A N/A N/A

FANS 1/A

ADS -C N/A Surveillance

• ADS -C

(CADS) Surveillance

• ADS -C N/A N/A

FANS 1/A N/A Surveillance

• ADS -C

(CADS) ATC

communication

• CPDLC Surveillance

• ADS -C N/A ATC

communication

• CPDLC for ACM, ACL,

and AMC

data link

services

FANS 1/A+ N/A Surveillance

• ADS -C

(CADS) ATC

communication

• CPDLC

Surveillance

• ADS -C N/A ATC

communication

• CPDLC for ACM, ACL,

and AMC data link

services

ATN B1 N/A N/A N/A ATC

communication

• CPDLC for ACM, ACL, and AMC

data link

services ATC

communication

• CPDLC for

ACM, ACL, and AMC

data link

services

FANS 1/A –

ATN B1 N/A Surveillance

• ADS -C

(CADS) ATC

communication

• CPDLC

Surveillance

• ADS -C ATC

communication

• CPDLC for ACM, ACL,

and AMC

data link

services ATC

communication

• CPDLC for ACM, ACL,

and AMC

data link

services

Note: B2 will be included at a later date.

10/3/17 AC 90 -117

2.14 Performance -Based Communication and Surveillance (PBCS) Concept. The PBCS

concept provides objective operational criteria to evaluate different and emerging

communication and surveillance technologies and is intended for evolving Air Traffic

System Management ( ATM ) operations. Once these criteria have been set and accepted,

a specific implementation of an ATM operation including its technical and human

performance may have its viability assessed against these operational criteria. ATS system changes based on communication and/or surveillance performance align

with the PCBS concept (refer to ICAO Doc 9869

).

2.14.1 Aligned with Performance- Based Navigation (PBN) . The PBCS concept is aligned with

the concept of PBN. While the PBN concept ap plies RNP and RNAV specifications to

the navigation element, the PBCS concept applies required communication performance (RCP) and required surveillance performance (RSP) specifications to communication and surveillance elements, respectively. Each RCP/RSP specification includes allocated

criteria among the components of the communication and surveillance systems involved.

2.14.2 Communication , Navigation , and Surveillance (CNS)/ATM Model . Where beneficial,

RCP, RNP/RNAV , and RSP specifications are applied to comm unication, navigation,

and surveillance elements to ensure the operational system and its components perform in

accordance with the specifications. Figure 2 -6, Performance -Based CNS/ATM Model,

provides an overview of the performance-based CNS/ATM model, which characterizes the relationship of the performance-based specifications among CNS elements supporting an ATM operation.

Note: Similar to the PBN concept, security is beyond the scope of the PBCS

concept. However, in some cases, the RCP and RSP specifications may include criteria to support mitigations from security threats.

Figure 2 -6. Performance -Based CNS/ATM Model

10/3/17 AC 90 -117

2.14.3 PBCS and PBN Differences . There are some differences between the PBCS concept and

PBN concept:

1. The PBCS concept applies RCP and RSP specificati ons, which allocate

criteria to ATS provision, including communication services, aircraft

capability, and the aircraft operator. The PBN concept applies RNP/RNAV specifications which allocate criteria only to the aircraft capability and the aircraft operat or; and

2. The PBCS concept includes post -implementation monitoring programs, on a

local and regional basis, with global exchange of information. The PBN concept includes real -time monitoring and alerting functionality in the aircraft

capability.

Note: PBCS includes real -time alerts (e.g. , when a communication transaction

expires or a position report is overdue) that are conceptually different than the

PBN alerts (e.g. , RNP UNABLE).

2.15 RCP and RSP Specifications Supporting ATM Operations. To perform ATM

operatio ns within a performance -based airspace, the standards specify functional, safety

and performance criteria for the applicable CNS elements. RCP and RSP specifications,

in conjunction with RNP/RNAV specifications , provide these criteria and are intended to

facilitate the development of standards for ATM operations. This approach is essential to

the evolution of operational concepts that use emerging technologies. For example, within the organized t rack s ystem (OTS) in North Atlantic High Level Airspace

(NAT HLA), the Redu ced Lateral Separation Minima (RLatSM) include the following

requirements:

• RNP 4;

• CPDLC with RCP 240; and

• ADS -C with RSP 180.

2.15.1 RCP Specifications . An RCP specification represents operational parameters for the

complete communication transaction . It is identified by a designator (e.g., RCP 240

or RCP 400) in order to simplify the designator naming convention and to make the RCP

Expiration Time (ET) readily apparent to airspace planners, aircraft manufacturers ,

and operators. The designator represents the value for the communication ET after which

the initiator is required to revert to an alternative procedure. The RCP specifications are

applied to achieve the performance required of the communication process and may

support aircraft separation minima.

2.15.2 RCP Parameters . The following describes the RCP parameters:

1. RCP Transaction Time. An RCP parameter that specifies t he maximum time

for the completion of a proportion of operational communication transactions

after which the initiator should revert to an alternative procedure . Two values

are specified:

10/3/17 AC 90 -117

• RCP T ransaction Time (TT). The maximum nominal time within which

95 percent of operational communication transactions is required to be

completed; and

• RCP ( ET). The maximum time for the completion of the operational

communication transaction, after which the initiator is required to revert to an

alternative procedure.

2. RCP Continuity (RCP C) . The minimum proportion of operational

communication transactions to be completed within the specified RCP transaction time, given the service was available at the start of the transaction .

3. RCP Availability (RCP A) . The required probability that an operational

communication transaction can be initiated .

4. RCP Integrity (RCP I) . The required probability that an operational

communication transaction is completed with no undetected errors.

Note: While RCP I is defined in terms of the “goodness” of the communications

capability, it is specified in terms of likelihood of occurrence of malfunction on a per flight hour basis (e.g., 10

-5), consistent with RNAV/RNP specifications.

Figure 2 -7. Actual Communications Performance (ACP)

10/3/17 AC 90 -117

2.15.3 RCP Framework and Actual Communication Performance (ACP). In Figure 2-7, Actual

Communication s Performance (ACP), the combined uplink and downlink performance of

ground systems, communication service, and aircraft systems is the A ctual

Communication T echnical P erformance (ACTP). Pilots an d controllers should respond

as soon as possible as part of the overall human performance. Human performance

combined with ACTP results in ACP. ACP is an indicator of the operational performance

of a communication system which includes the human and technical components. Human performance considers such facto rs as training, procedures, and human -machine i nterface

(HMI). Technical performance comprises the installed elements of communication performance operating together to meet the intended function. ACP is assessed in the

same terms and parameters as an RC P specification, its allocations, and other relevant

operational criteria provided by an RCP specification. Operationally, an appropriate level of communication performance is required for aircraft systems, communications networks, and ground systems.

Note: In ICAO documentation, pilot response time is called Pilot Op erational

Response Time (PORT).

Figure 2-8. RCP 240 Illustration

10/3/17 AC 90 -117

2.15.4 RCP 240 Illustration. As i llustrated in Figure 2-8, RCP 240 Illustration, the controller

sends a data link communication message through the ATSU via the CSP to the aircraft.

The Required Communication Technical Performance (RCTP) is the overall time for the

communication to travel from the ATSU to the flight deck and return excluding human

response t ime. RCTP should be less than or equal to 150 seconds for 99.9 percent of the

operational time (ET) and must be less than or equal to 120 seconds for 95 percent of the

nominal time (TT). The message arrives at the flight deck and the pilot should respond a s

soon as possible (i.e. , ROGER (DM3)/WILCO (DM0), UNABLE (DM1) , or STANDBY

(DM2)) . The pilot responds to the message and it travels back to the ATSU.

2.15.5 RCP 240 Specification Tables . Table 2 -4, RCP 240 Transaction Time and Continuity

Allocations –CPDLC, shows Transaction Time and Continuity allocations from the sender

(controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system . Table 2 -5, RCP 240 Availability Criteria

(Aircraft System), provides the aircraft system availability criteria. Table 2 -6, RCP 240

Integrity Criteria (Aircraft System), provides the integrity criteria for the aircraft system.

Table 2 -4. RCP 240 Transaction Time and Continuity Allocations —CPDLC

ACP Controller ATSU

system Network Aircraft

system Pilot

Response Aircraft

system Network ATSU

system Controller

99.9% (ET) PC/ATSU (30) PATSU(15) PNET(120) PAIR(15) 60 PAIR(15) PNET(120) PATSU(15) PC/ATSU (30)

95% (TT) PC/ATSU (30) PATSU(10) PNET(100) PAIR(10) 60 PAIR(10) PNET(100) PATSU(10) PC/ATSU (30)

Table 2 -5. RCP 240 Availability Criteria (Aircraft System)

Availability Parameter Efficiency Safety Compliance Means

Availability – aircraft (A AIR) N/A 0.999 Analysis, architecture, design,

pre-implementation

demonstration

Table 2 -6. RCP 240 Integrity Criteria (Aircraft System)

Integrity Parameter Integrity Value Compliance Means

Integrity (I) Malfunction =

10-5 per flight

hour Analysis, safety requirements, development assurance level

(e.g. Level C software) commensurate with integrity level,

pre-implementation demonstration.

10/3/17 AC 90 -117

Figure 2-9. RCP 400 Illustration

2.15.6 RCP 400 Illustration. As illustrated in Figure 2 -9, RCP 400 Illustration, the controller

sends a data link communication message through the ATSU through the CSP to the

aircraft. The RCTP is the overall time for the communication to travel from the ATSU to

the flight deck and return excluding human factors. RCTP should be less than or equal to 310 seconds for 99.9 percent of the operational time (ET) and must be less than

or equal to 260 seconds for 95 percent of the nominal time (TT). The message arrives at

the flight deck and the pilots should respond as soon as possible (i.e., ROGER (DM3)/WILCO (DM0), UNABLE (DM1) , or STANDBY (DM2) ). The pilot responds to

the message and it travels back to the ATSU.

2.15.7 RCP 400 Specification Tables . Table 2-7 , RCP 400 Transaction Time and Continuity

Allocations —CPDLC, shows Transaction Time and Continuity allocations from the

sender (controller) to responder (pilot) and back to sender (controller). RCTP consists of the ATSU system, network, and the aircraft system . Table

2-8, RCP 400 Availa bility

Criteria (Aircraft System), provides the availability criteria for the aircraft system.

Table 2-9, RCP 400 Integrity Criteria (Aircraft System), provides the integrity criteria for

the aircraft system.

10/3/17 AC 90 -117

Table 2 -7. RCP 400 Transaction Time and Continuity Allocations —CPDLC

ACP Controller ATSU

system Network Aircraft

system Pilot

Response Aircraft

system Network ATSU

system Controller

99.9%

(ET) PC/ATSU (30) PATSU(15) PNET(280) PAIR(15) 60 PAIR(15) PNET(280) PATSU(15) PC/ATSU (30)

95%

(TT) PC/ATSU (30) PATSU(10) PNET(240) PAIR(10) 60 PAIR(10) PNET(240) PATSU(10) PC/ATSU (30)

Table 2 -8. RCP 400 Availability Criteria (Aircraft System)

Availability Parameter Efficiency Safety Compliance Means

Availability – aircraft (A AIR) N/A 0.999 Analysis, architecture, design,

pre-implementation

demonstration

Table 2 -9. RCP 40 0 Integrity Criteria (Aircraft System)

Integrity parameter Integrity value Compliance means

Integrity (I) Malfunction =

10-5 per flight

hour Analysis, safety requirements, development assurance level

(e.g. Level C software) commensurate with integrity level,

pre-implementation demonstration.

2.16 Required Surveillance Performance (RSP).

2.16.1 Background. In the past, surveillance over oceanic and remote continental areas was

limited to pilot position reports via HF radio. When crossing a compulsory reporting

point, the pilot would contact the ATSU via a radio operator and report: identification, position, time, altitude, next PR point, name of succeeding reporting point, and remarks.

Once the aircraft entered a radar environment, pilot reports were eliminated. Today, along with voice pilot position reports, surveillance in oceanic and remote continental airspace is accomplished much more accurately through the use of ADS -C. As with

CPDLC, ADS -C requires certain performance requirements for operational surveillance

in support of specific ATM functions. This includes the transmission of aircraft position, velocity and intent with a specified precision, accuracy and update ra tes. In combination

with RCP and RNP, RSP enables the efficient use of airspace by allowing reduced lateral and along -track separation of aircraft by supplying accurate and frequent updates of

aircraft position.

2.16.2 RSP Concept . The concept of RSP relates to t he surveillance component and

complements RNP and RCP. A collective set of performance measures are established to ensure overall communication transactions and surveillance data deliveries are suitable

for certain surveillance related goals. For example, the surveillance goal may be to

achieve 3 0 nautical miles (NM) lateral and 30 NM along -track separation in oceanic

10/3/17 AC 90 -117

airspace. RSP is operationally derived and not based on any specific techniques, aircraf t

technologies , or architecture.

2.16.3 RSP Specification . An RSP specification is identified by a designator (e.g. , RSP 180)

in order to simplify the designator naming convention and to make the RSP D ata

Operational Overdue T ime (OT) readily apparent to airspace planners, aircraft

manufacturers and operators. The designator represents the value for the surveillance

data delivery time when the surveillance data deli very is considered overdue.

RSP specifications are applied to airspace based on specif ic objectives (e.g. , the

performance required of the surveillance process used to support particular separation minima ). The RSP specification is a set of requirements/operational parameters for ATS

provision and associated ground equipment, aircraft capability, and operations needed to support performance -based surveillance. Surveillance performance requirements are

included and allocated to system components (Required Surveillance Technical Performance (RSTP)). It includes surveillance data delivery time, continuity, availability,

integrity , and safety . A specified RSP specification is intended to define the surveillance

performance required of a surveillance process to support a particular ATM function. RSP specification is applied to the a irspace, route, or procedure based on the most

stringent RSP specification of the required ATM functions.

2.16.4 RSP Parameters . RSP include the accuracy of the reported position, the latency in

reporting the position to the controller, and the integrity, availability, and continuity of the surveillance data. The following describes the RSP parameters:

1. RSP Surveillance Data Transit Time. The maximum time for the reception of the surveillance data after which the controller should revert to an alternative procedure .

2. RSP Continuity. The minimum proportion of surveillance data delivery to be completed within the specified RSP surveillance data delivery time, given the service was available at the start of the delivery.

3. RSP Availability. The required probability that surveillance data can be provided.

4. RSP Integrity. The required probability that surveillance data delivery is completed with no undetected errors.

10/3/17 AC 90 -117

Figure 2-10. RSP 180 Illustration

2.16.5 RSP 180 Illustration. In Figure 2 -10, RSP 180 Illustration, the ATSU establishes an event

contract with the aircraft with specific allocations described below :

1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required

to respond within 5 seconds or less 99.9 percent of the operational time (OT)

and less than or equal to 3 seconds 95 percent of the nominal delivery

time (DT).

2. From 2 to 3 (CSP). The signal is then transmitted through the communication service provider (CSP) network. This action must occur within 170 seconds or less for 99.9 percent of the OT and less than or equal to 84 seconds 95 percent

of the DT .

3. From 3 to 4 (ATSU). From the (CSP) th is message is sent through the ATSU

which has a required performance of less than or equal to 5 seconds for 99.9 percent of the time and less than or equal to 3 seconds for 95 percent of

the time. The total communication from the event to the controller must be less than or equal to 180 seconds with 99.9 percent probability ( OT) and

less than or equal to 90 seconds with 95 percent probability ( DT).

2.16.6 RSP 180 Specification Tables. Table 2-10

, RSP 180 Surveill ance Data Delivery and

Continuity Allocations— ADS -C, shows allocations for Required Surveillance

Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP)

consisting of the aircraft system , network and ATSU. Table 2-11, RSP 180 Availability

Criteria (Aircraft System), provides the availability criteria for the aircraft system.

10/3/17 AC 90 -117

Table 2- 12, RSP 180 Integrity Criteria (Aircraft System) provides the integrity criteria for

the aircraft system.

Table 2 -10. RSP 180 Surveillance Data Delivery and Continuity Allocations —ADS -C

RSMP/RSTP Aircraft system Network ATSU

99.9% (OT) 5 170 5

95% (DT) 3 84 3

Table 2 -11. RSP 180 Availability Criteria (Aircraft System)

Availability Parameter Efficiency Safety Compliance Means

Availability – aircraft (A AIR) N/A 0.999 Analysis, architecture, design,

pre-implementation

demonstration

Table 2 -12. RSP 180 Integrity Criteria (Aircraft System)

Integrity parameter Integrity value Compliance means

Integrity (I) Malfunction =

10-5 per flight

hour Analysis, safety requirements, development assurance level

(e.g. Level C software) commensurate with integrity level,

pre-implementation demonstration.

10/3/17 AC 90 -117

Figure 2-11. RSP 400 Performance

2.16.7 RSP 400 Illustration. In Figure 2 -11, RSP 400 Performance, the ATSU establishes

an event contract with the aircraft with specif ic allocations described below.

1. From 1 to 2 (Aircraft). The aircraft reaches the particular event and is required

to respond within 30 seconds or less 99.9 percent of the OT and less than or

equal to 15 seconds 95 percent of the DT .

2. From 2 to 3 (CSP). The signal i s then transmitted through the CSP network.

This action must occur within 340 seconds or less for 99.9 percent of the OT

and less than or equal to 270 seconds 95 percent of the DT .

3. From 3 to 4 (ATSU). From the CSP th is message is sent through the ATSU

which has a required perfor mance of less than or equal to 30 seconds for

99.9 percent of the time and less than or equal to 15 seconds for 95 percent of

the time. The total communication from the event to the controlle r must be

less than or equal to 400 seconds with 99.9 percent probability ( OT) and

less than or equal to 300 seconds with 95 percent probability ( DT).

2.16.8 RSP 400 Specification Tables. Table 2-13 , RSP 400 Surveillance Data Delivery and

Continuity Allocations —ADS -C, shows allocations for Required Surveil lance

Monitoring Performance/Required Surveillance Technical Performance (RSMP/RSTP)

consisting of the aircraft system, network and ATSU. Table 2-14, RSP 400 Availability

Criteria (Aircraft System), provides the availability criteria for the aircraft system.

Table 2-15, RSP 400 Integrity Criteria (Aircraft System), provides the integrity criteria

for the aircraft system.

10/3/17 AC 90 -117

Table 2 -13. RSP 400 Surveillance Data Delivery and Continuity Allocations —ADS -C

RSMP/RSTP Aircraft system Network ATSU

99.9% (OT) 30 340 30

95% (DT) 15 270 15

Table 2 -14. RSP 400 Availability Criteria (Aircraft System)

Availability Parameter Efficiency Safety Compliance Means

Availability – aircraft (AAIR) N/A 0.999 Analysis, architecture, design,

pre-implementation

demonstration

Table 2 -15. RSP 400 Integrity Criteria (Aircraft System)

Integrity parameter Integrity value Compliance means

Integrity (I) Malfunction =

10-5 per flight

hour Analysis, safety requirements, development assurance level

(e.g. Level C software) commensurate with integrity level,

pre-implementation demonstration. The aircraft end system

shall be capable of detecting errors that would result in

corruption, introduced by the co mmunication service.

2.17 High Frequency Data Link (HFDL). Over the past few decades HF has provided an

effective means of voice communication over long distance in oceanic and remote

continental airspace. HF communication is no longer restricted to voice and provides

another means of sending and receiving digital communication. HFDL augments existing VHF and satellite communications (SATCOM ) (i.e., CPDLC and ADS -C) data link

communication systems. A subnetwork of 15 HFDL ground stations extends worldwide

commu nication coverage beyond that of VHF data link communication subnetworks.

2.17.1 HFDL Applications . HFDL subnetwork provides communication to both ATSU and

AOC in oceanic and remote continental airspace and can be used for:

1. Non-SATCOM equipped aircraft with a long -range, cost -effective data link

communication capability,

2. Data link communication in polar regions where geostationary satellite connections may not exist or be degraded, and

3. A back -up means of data link communication for SATCOM (CPDLC and

ADS -C) equi pped aircraft.

10/3/17 AC 90 -117

2.17.2 Ionosphere HF Disturbance and Reliability . HF is subject to temporary signal distortion

due to changes in the ionosphere layer shape and density. Because of multiple H FDL

ground stations, ionosphere disturbances are less frequent than in the early days of

HF voice. Modern aircraft HFDL systems automatically search for the best available

frequency from all HFDL operational ground station frequencies. Once a suitable

frequency is found, the aircraft establishes a connection by sending a logon/n otification

message to the ground station. A logon/notification confirmation uplink is established

enabling the pilot to send data.

Note: Monitoring data have shown that HFDL does not meet RCP 240/RSP 180.

2.18 Future U.S. Domestic Airspace Data Link Communication Se rvices. Figure 2 -12

depicts future plans for data link communication services. Though this planning diagram is subject to change, it generally provides a preview of expanding data link servi ces in the

next few years. This is added to the AC to enable operators planning upgrades in pace

with future technology and upcoming data link communication services.

Figure 2-12. Data Communication Services Strategy

10/3/17 AC 90 -117

2.19 Data Communication Services Strategy. Segment 1 in Figure 2-12 consists of

two phases .

2.19.1 Tower Services and En Route Services . Segment 1, Phase 2 (S1P2) services will be

delivered in two stages, “initial” services and “full” services. S1P2 en route services are

expected to begin in 2019 and are planned to leverage exis ting Phase 1 FANS 1/A

aircraft and expand Phase 1 infrastructure to deliver CPDLC services in the

U.S. domestic en route airspace. Listed below are en route initial and full services:

1. En R oute Initial Services. The initial services in S1P2 will include

the following:

• Transfer of communications,

• Initial check -in,

• Altimeter settings,

• Altitudes,

• Speed (limited),

• Crossing Restrictions (limited),

• Airborne reroutes/go button,

• Controller initiated reroutes (limited), and

• Direct -to-fix (initial).

2. En Route Full Services. With the continuation of S1P2, en route full services

will include (see the following paragraphs for descriptions of some initial and

full service features ):

• Controller initiated routes,

• Crossing restrictions,

• Direct -to-fix,

• Advisory messages, and

• Holding instructions.

Note: The full services of speed, stuck microphone, adapted arrivals , and beacon

codes are deferred until further notice.

2.19.2 Speeds .

1. Initial Services. The controller can issue UM61 CROSS (position) AT AND

MAINTAIN (altitude) AT (speed).

2. Full Services (Deferred). The controller will be able to:

• Issue speed clearance providing the pilot with instructions to maintain a speed

in Mach number or indicated airspeed,

10/3/17 AC 90 -117

• Assign speeds of greater than or less than specific values , and

• Instruct the pilot to resume normal speed or to maintain present speed. The pilot

will be able to request a speed clearance.

2.19.3 Crossing Restrictions . Initially, the controller will be able to use two crossing restriction

message elements to instruct the pilot to cross a specific fix at a specific altitude and,

if desired, at a specific speed. With full service, the controller will have considerably

more flexibility in composing crossing restriction clearances. For example, the controller

will be able to clear an aircraft to cross a specific fix at a specific time and have the option of entering a crossing restriction.

2.19.4 Routes . Initially, the pilot will be able to DM22 RE QUEST DIRECT TO (position).

The controller will be able to issue route clearances, such as UM74 PROC EED

DIRECT TO (position), UM79 CLEARED TO (position) VIA (r oute clearance),

UM80 CLEARED (route clearance) , and UM83 AT (position) CLEARED

(route clearance). With full service, the controller’s workstation will be enhanced to

support entry from the Radar (R) and Radar Associate (RA ) positions and permit entry

of route offsets with additional message elements.

2.19.5 Advisory . Air Traffic personnel issue advisory messages t o aircraft on a routine basis.

Examples include dynamic airport information (runway closures, runway visual range, braking action, etc.), convective s ignificant m eteorological i nformation (SIGMET),

Cent ral Weather Advisories (CWA), Pilot Weather Reports (PIREP), weather displayed

on the controller’s scope, and current ride reports. CPDLC will allow the controller to send a limited set of advisory messages to the aircraft on a case -by-case basis or to all

aircraft with which the controller has a CPDLC connection. Advisory messages such as SIGMET s and CWAs, which must be broadcast to all aircraft on frequency, will still

need to be verbally broadcast in a mixed equipage environment. However, advisory messages that are issued to individual aircraft, such as dynamic airport information, displayed weather, PIREPS, and current ride reports are excellent candidates for

automating. S1P2 CPDLC services will only support ride reports and free text messages created at the sector. The messages will be provided to the controller to send to the appropriate aircraft. In addition to free ing the controller from verbally delivering the

advisory, CPDLC also allows positive confirmation that affected aircraft have received the information.

2.19.6 Holding Instructions . The controller may be directed to hold all arrivals for a particular

airport. With full service, the controller will be able to send a CPDLC message UM91 HOLD AT (position) MAINTAIN (altitude) INBOUND TRACK (degrees) (direction) TURN LEG TIME (leg type).

2.19.7 Stuck Microphone ( Deferred). With full service, the controller will be able to instruct the

pilot to check their microphones.

2.19.8 Adapted Arrivals ( Deferred) .With full service, the controller and pilot will be able to use

CPDLC to execute adapted arrival procedure. The adapted procedure contains both lateral and vertical aircraft maneuvers and provides greater efficiency for users.

10/3/17 AC 90 -117

2.19.9 Beacon Codes ( Deferred) . As aircraft transition in U.S. domestic airspace from

one facility to another, there is the possibility of beacon code duplication. Often this

happens when there is significant traffic and/or delays in the system. It is also prevalent

at facilities which border foreign airspace. Today, when this conflict occurs, En Route

Automation Modernization (ERAM) will assign the aircraft a new code and notify the controller, who then verbally issues it to the pilot. With CPDLC, the FAA ground

system will automatically send a UM with the new code to the aircraft at the appropriate

time with no controller inv olvement. The controller will also be able to manually

compose and send a beacon code message if needed.

10/3/17 AC 90 -117

CHAPTER 3. AIRCRAFT ELIGIBILITY

3.1 Introduction. This chapter provides guidance on how operators can determine if their

aircraft dat a link system is compliant and el igible for operational use. This AC does not

address design approval or installation of data link systems. For airworthiness guidance,

refer to AC 20-140( ), Guidelines for Design Approval of Aircraft Data Link

Communication Systems Supporting Air Traffic Services ( ATS).

3.2 Aircraft Eligibility. The Airplane Flight Manual (AFM) should identify the following

for data link communication eligibility:

1. Interoperability,

2. Subnetwork, and

3. Aircraft performance.

Note: Descriptions of the data link services are p rovided for a given airspace

or operation. For exam ple, in the United States , departure clearance

(Controller -Pilot Data Link Communication –Departure Clearance

(CPDLC -DCL )) service requires the aircraft to be interoperable with Future Air

Navigation Systems (FANS )-1/A(+), to use either the Very High Frequency

(VHF) Data Link ( VDL ) Mode 0/A or VDL Mode 2 subnetwork, and to not have

any prescribed aircraft performance requirements. Operators should refer to the requirements defined by the Air Traffic Service Unit (ATSU) for each operation.

A summary of typica l operational requirements is provided in Chapter 5

,

Operational Use of Data Link Communications, of this AC.

3.3 Statement of Compliance (SOC). Due to the complexity of the criteria to determine

eligibility, the operator must obtain a statement of compliance from the entity that owns

the design approval for their data link installation. This may be the aircraft manufacturer, the operator, the manufacturer of the data link system, or another party. The statement of complia nce should be provided in the AFM , AFM S upplement , or other acceptable

document . Table C -3

, Preferred Original Equipment Manufacturer Annotation, provides

an example of a statement of compliance. The statement of compliance mus t indicate the

aircraft data link system meets the aircraft -allocated requirements of Required

Communication Performance (RCP) and Required Surveillance Performance (RSP) specifications.

Note: For a FANS 1/A CPDLC and Automatic Dependent Surveillance- Contract

(ADS-C) aircraft system, RTCA DO- 306/European Organization for Civil

Aviation Equipment ( EUROCAE ) ED-122, Safety and Performance Standard for

Air Traffic Data Link Services in Oceanic and Remote Airspace (Oceanic SPR

Standard), is equivalent to RCP 240, RCP 400, RSP 180, and RSP 400 specifications. For an Aeronautical Telecommunication s Network (ATN)

Baseline 1 (B1) or FANS 1/A CPDLC aircraft system, RTCA

DO-290/ED-120,

Safety and Performance Requirements Standard for Air Traffic Data Link

10/3/17 AC 90 -117

Services in Continental Airspace (Continental SPR Standard), provides

performance criteria for the EUR Re gion.

3.3.1 Alternate Means of Compliance for No SOC . In lieu of the SOC stated in the AFM,

AFM Supplement, or other acceptable documentation, operators may provide a detailed

submission to the FAA validating that the aircraft ’s current system meets the RCP /RSP

applicable requirements. As a minimum, this submission should inclu de information on

avionics continuity, integrity, availability , and safety and monitoring/alerting

requirements ( refer to RTCA DO- 306/ED -122). Equipment manufacturer support should

be solicited to acquire suitable documentation.

3.3.2 Interoperability . The opera tor must confirm the interope rability of their aircraft data link

system ( interoperability requirements standards ( INTEROP ) designators are described in

Table 2-2, Interoperability Designators and Descriptions ). The statement of compliance

must indicate the INTEROP and a reference to the definition of that INTEROP. Aircraft

Communication s Addressing and Reporting System (ACARS ) ATS, FANS 1/A,

FANS 1/A+, and ATNB1 INTEROP designators, and/or the compliance statemen t,

must reference AC 20 -140 or later revision. For the ATN Baseline 2 ( B2) INTEROP

designator, the compliance statement must reference AC 20 -140C or later revision.

3.3.2.1 In U.S. domestic en route airspace , for operations supported by FANS 1/A(+)

data link communication systems, the avionics system must have

“push to load” capability into the navigation system whenever a routing

change (e.g., uplink message ( UM)79, UM80, and UM83) is received .

Note: Operators using an alt ernate means of compliance for “push to

load” will not be permitted once full services are implemented.

“Full services ” require fully inte grated (“push to load” ) avionics. For a

description of “F ull Services ,” see Figure 2- 12, Data Communication

Services Strategy .

3.3.3 Subnetwork . The operator must confirm the subnetwork capability of their aircraft

(subnetworks are described in paragraph 2.2.2 ). The statement of compliance must

indicate the subnetworks that are supported and a ref erence to the definition of

the subnetworks. The compliance statement must reference AC 20 -140 or later for any

of the following subnetworks:

• VDL M0/A,

• VDL M2,

• High Frequency Data Link ( HFDL ),

• Inmarsat , and

• Satellite communications ( SATCOM ) Iridium ( Short Burst Data ( SBD )).

Note: For aircraft utilizing Inmarsat (SwiftBroadband ( SBB )), the SOC must

reference AC 20-140C or later.

10/3/17 AC 90 -117

3.3.4 VDL M2 Requirements for U.S. Domestic En R oute. The VDL M2 requirements

include aircraft that are equipped with VD L Mode 2 equipment approved to Technical

Standard Order ( TSO )-C160a , Very High Frequency (VHF) Digital Link (VDL) Mode 2

Communications Equipment, (see Note 1 below for details) or later that is capable

of tuning to more than one VDL M2 channel .

Note 1: Minimum performance standard of TSO -C160 does not include the

capability for the Communications Management Unit ( CMU ) (Avionics

Architecture Class W and Z) or VDL M 2 Radio (Avionics Architecture Class X)

to tune to more than one VDL M2 channel . The above equipment is capable of

tuning to only one VDL M2 channel (i.e ., 136.975 MHz). The m inimum

performanc e standard of TSO -C160 for VDL M 2 Radio (Avionics Architecture

Class V or Y) contains the capability to support V DL M ode 2 multi -frequency

operation when integrated with a CMU (Avionics Architecture Class W and Z)

that supports VDL M 2 multi -frequency according to TSO -C160a .

Note 2: The FAA accepts the us e of VDL M0/A en route when VDL M2

communications are lost, if the aircraft is equipped with a properly functioning

VDL M2 radio before starting the flight or dispatching. An a lternate subnetwork

may be used provided it complies with paragraph 4.6.2. Table C -1, Summary of

Airspace Requirements, provides a summary of airspace requirements.

3.3.5 Performance Data for Compliance. The operator should evaluate the demonstrated

performance of their aircraft data link system as provided by the FAA and other

Air Navigation Services Providers ( ANSP ) as part of the ANSP monitoring programs.

FAA monitoring data is available for initial and continuous compliance and operator data may be acceptable for init ial data link eligibility. Actual Communication s Performance

(ACP) of the CPDLC two -way communications and Actual Surveillance P erformance

(ASP) of the ADS -C are evaluated against respective RCP and RSP specification

standards. This data should be included to quantify support of the aircraft performance

portion of the data link eligibility. If no performance data is available, then initial compliance for applicable ai rspace will be based on the SOC with performance being

monitored as data is collected. (See Chapter

6, Performance Monitoring.)

Note 1: For fleet aircraft, records for every tail number are not necessary provided that

all the aircraft have the same data link communication configuration. Operators with a single aircraft may meet the above requirement using records o f other aircraft with the

same m ake, m odel, and s eries (M/M/S) and the same data link communication

configuration.

Note 2: RCP and RSP performance data is not required for aircraft operating only in

U.S. domes tic airspace.

3.4 Configuration Control. Operators should maintain their aircraft in an avionics

configuration which has been shown to provide acceptable data link communication

performance. A list of recommended avionics is available at

http://dcis.harris.com/new -

operator -documents .

10/3/17 AC 90 -117

3.5 Maintenance. The operator is responsible for all maintenance of data link

communication systems. Maintenance procedures for data link communications are

approved or accepted as part of an operator’s initial maintenance manual approval or as a revision to that manual.

Note: Maintenance facilities conducting Supplemental Type Certificate ( STC)

modifications must coordinate Master Minimum Equipment List

(MMEL )/minimum equipment list ( MEL ) changes that include all data

communications equipment with the Aircraft Evaluation Group ( AEG ).

The Original Equipment Manufacturer ( OEM ) or the holder of installation

approval for the aircraft (e.g., STC holder) must demonstr ate compliance with the

criteria in this AC. An STC for additional installed items must document any applicable MEL relief.

3.5.1 System Alteration ( Including S oftware U pdates) . Operators must evaluate alterations to

the aircraft and identify any changes to aircraft eligibility. The owner of the design approval for the alteration must confirm the alteration did not affect the data link system. If the alteration affected the data link system, the owner of the design must provide a statement of compliance to the as sociated INTEROP, subnetworks and performance

standards. Operators must determine aircraft eligibility after each alteration .

3.5.2 Subnetwork Configuration for Route Coverage . The operator must ensure communication

coverage capability of their aircraft’s subnetwork for the route to be flown (see paragraph

4.1.3 ). For adequate coverage, operators may have to adjust their aircraft’s

media management parameters (e.g. , where the system automat ically switch es from V DL

to SATCOM) . Operators have experienced unacceptable performance transitioning

airspace with marginal VDL coverage because the aircraft tries to maintain or reestablish a VDL connection. Some States may also limit the s ubnetworks that can be used

for operation.

10/3/17 AC 90 -117

CHAPTER 4. COMMUNICATION SERVICE PROVIDERS (CSP)

4.1 CSP for Oceanic and Remote Continental Operations. For oceanic and remote

continental operations using data link communications, operators are responsible for

ensuring their CSP meets the minimum specifications of this chapter. The operator/CSP agreement must include these requirements in addition to monitoring their performance as addressed in Chapter 6

, Performance Monitoring .

4.1.1 Substandard Performance . If a CSP fails to satisfy the allocated requirements,

the operator should not file or use the associated performance standard until the problem

is resolved. An exception is allowed for performance below the 99.9 percent operational

transaction time which permits the operator to continue to operate at the 95 percent

nominal transaction time or greater while investigating the issue for corrective action.

4.1.2 CSP and Operator Arrangements . Operators must ensure the services they have arranged

with the ir CSP(s) include:

1. Failure notification,

2. Recording data link messages,

3. CSP i ntegrity,

4. Compliance with CSP allocations for Required Communication Performance (RCP )/Required Surveillance Performance ( RSP), and

5. Adequate subnetwork coverage for the route flown.

4.1.2.1 Failure Notification. The CSP should notify the operator and any affected

Air Traffic Service Units (ATSU) of any failure condition that may impact data link communication operations (such as coverage or performance).

This includes when a CSP holds an ag reement with an aircraft operator but

not with the affected ATSU.

4.1.2.2 Recording Data Link Messages. The operator should ensure that they have

access to communication and surveillance data sent or received to their

aircraft for at least 30 days. The CSP(s) should retain records for at least

30 days to allow for accident/incident investigation purposes. The operator or CSP should make these records available for air safety investigative

purposes on request .

4.1.2.3 CSP Integrity. The CSP must pass messages without manipulating the

information protected by error detection codes used by the a ircraft system and

the ATSU. In particular, the CSP must not reconstitute or regenerate any of

the error detection codes.

4.1.2.4 RCP Allocation Requirements . The operator must ensure the CSP satisfies

the allocated requirements for any RCP used by the operator. The CSP has two points of demarcation with an ATSU domain consisting of ground router to ground router interface and two signal in space point s of demarcation with

10/3/17 AC 90 -117

aircraft’s data link communication system. The downlink message enters the

CSP domain at the first emission of the first bit of the first frame from the

aircraft’s data link communication system. For uplink message (UM), it exits

the CSP domain at the last emission of the last bit of the last frame to the

aircraft’s data link communication system. The Required Communication

Technical Performance ( RCTP )CSP is the two -way transfer delay from when

a message (e.g. , UM ) is received from the ATSU at the CSP point of

demarcation (e.g. , enters from the ground domain) until its successful arrival

at the CSP ’s signal in space point of demarcation. W hen the message is

answer ed, it arrives at the signal in space CSP point of demarcation and

continues the CSP’s ground router to g round router interface back to the

ATSU. It includes delay such as propagation delay and retransmissions,

as well as subnetwork delays resulting from queueing/flow control,

segmentation, processing, ground -network transmission, routing, etc.

4.2 RCP 240 CSP Al locations. The CSP must meet the performance requirements described

in Table 4 -1, RCP 240 Transaction Time and Continuity Allocations to CSP, and

Table 4- 2, RCP 240 CSP Availability and Outages Parameters, where RCP 240 has been

prescribed on t he routes flown by the operator.

Table 4 -1. RCP 240 Transaction Time and Continuity Allocations to CSP

Transaction T ime Parameter *ET (sec)

99.9% of

messages

less than:

(sec) **TT (sec)

C = 95% of

messages

less than:

(sec) Compliance M eans

RCTPCSP 120 100 Contract/service agreement

terms. See also paragraph 4.1.2.

*ET is Expiration Time

**TT is Transaction Time

Table 4 -2. RCP 240 CSP Availability and Outages Parameters

Availability Parameter Safety Compliance M eans

Availability – CSP (ACSP) 0.999 Contract/service agreement terms

Unplanned outage duration limit (minutes) 10 Contract/service agreement terms

Maximum number of unplanned outages 48 Contract/service agreement terms

Maximum accumulated unplanned outage time

(minutes/year) 520 Contract/service agreement terms

Unplanned outage notification delay (minutes) 5 Contract/service agreement terms

10/3/17 AC 90 -117

4.3 RCP 400 CSP Allocations. The CSP must comply with the performance described in

Table 4 -3, RCP 400 Transaction Time and Continuity to CSP Allocation, and Table 4 -4,

RCP 400 Availability and Outages Parameters, along the route to be flown by the

operator .

Table 4 -3. RCP 400 Transaction Time and Continuity to CSP Allocation

Transaction T ime Parameter *ET (sec)

C = 99.9%

of

messages

less than:

(sec) **TT (sec)

C = 95%

of

messages

less than:

(sec) Compliance M eans

RCTPCSP 280 240 Contract/service agreement terms

See also paragraph 4.1.2.

*ET is Expiration Time

**TT is Transaction Time

Table 4 -4. RCP 400 Availability and Outages Parameters

Availability Parameter Requirement Compliance M eans

Availability – CSP (ACSP) 0.999 Contract/service agreement terms

Unplanned outage duration limit (minutes) 20 Contract/service agreement terms

Maximum number of unplanned outages 24 Contract/service agreement terms

Maximum accumulated unplanned outage time

(minutes/year) 520 Contract/service agreement terms

Unplanned outage notification delay (minutes) 10 Contract/service agreement terms

10/3/17 AC 90 -117

4.4 RSP Allocation Requirements . The operator must ensure the CSP satisfies the allocated

requirements for any RSP used by the operator. The Required Surveillance Technical

Performance (RSTP) CSP is the one -way transfer delay f rom when a message is received at

the CSP’s signal in space point of demarcation until its successful arrival at the other CSP’s ground router to ground router point of demarcation to the ATSU. It includes delay such as propagation delay and retransmissions, as well as subnetwork delays resulting from queueing/flow control, segmentation, processing, ground- network

transmission, routing, etc. Delay is measured from the first bit emission of the first bit of

the first frame/data packet from the aircraft’s Data Link Radio to the last bit exiting the CSP domain when it is received by the ground domain (ATSU).

4.4.1 RSP 180 CSP Allocations . The CSP must comply with the performance described in

Table 4 -5, RSP 180 Data Delivery Time and Continuity Criteria, and Table 4 -6, RSP 180

Availability and Outages Parameters .

Table 4 -5. RSP 180 Data Delivery Time and Continuity Criteria

Data D elivery T ime Parameter *OT (sec)

C = 99.9%

of messages

less than:

(sec) **DT (sec)

C = 95% of

messages

less than:

(sec) Compliance M eans

RSTPCSP 170 84 Contract/service agreement

terms. Pre- implementation

demonstration.

*OT is data overdue time (associated with operational continuity)

**DT is Delivery Time

Table 4 -6. RSP 180 Availability and Outages Parameters

Availability Parameter Safety Compliance M eans

Availability – CSP (ACSP) 0.999 Contract/service agreement terms

Unplanned outage duration limit (minutes) 10 Contract/service agreement terms

Maximum number of unplanned outages 48 Contract/service agreement terms

Maximum accumulated unplanned outage time

(minutes/year) 520 Contract/service agreement terms

Unplanned outage notification delay (minutes) 5 Contract/service agreement terms

4.4.2 RSP 400 CSP Allocations . The CSP must comply with the performance described in

Table 4- 7, RSP 400 Data Delivery Time and Continuity Criteria, and Table 4-8, RSP 400

Availability and Outages Parameters .

10/3/17 AC 90 -117

Table 4 -7. RSP 400 Data Delivery Time and Continuity Criteria

Data D elivery T ime Parameter OT (sec)

C = 99.9%

of messages

less than:

(sec) DT (sec)

C = 95% of

messages

less than:

(sec) Compliance M eans

RSTPCSP 340 270 Contract/service agreement

terms. Pre- implementation

demonstration.

*OT is data overdue time (associated with operational continuity)

**DT is Delivery T ime

Table 4 -8. RSP 400 Availability and Outages Parameters

Availability Parameter Safety Compliance M eans

Availability – CSP (ACSP) 0.999 Contract/service agreement terms

Unplanned outage duration limit (minutes) 20 Contract/service agreement terms

Maximum number of unplanned outages 24 Contract/service agreement terms

Maximum accumulated unplanned outage time

(minutes/year) 520 Contract/service agreement terms

Unplanned outage notification delay (minutes) 10 Contract/service agreement terms

4.5 Alternate Means of Compliance. A Performance- based Communication and

Surveillance (PBCS) Charter is available as an alternate means of compliance to validate

the operator/CSP agreement for performance and services stated in this AC. Operators and CSPs need only to become charter members by following the instructions at

http://www.fans -cra.com/

. Operators who are seeking an Operations Specification

(OpSpec)/Management Specification (MSpec)/Letter of Authorization (LOA) A056, Data Link Communications, authorization and are charter members satisfy their

responsibility of ensuring their CSP meets the minimum specifications of this chapter provided that their CSP is also a charter member. Charter members using this alternate means of compli ance must remain as charter members or notify their responsible Flight

Standards office of their change in status.

Note: A change of charter membership status will affect operational

authorization.

4.6 CSP for U .S. Operations. The FAA provides Very High Frequency (V HF) Data Link

(VDL ) Mode 2 for all data link operations within the domestic U nited S tates (except

oceanic and remote continental areas, which fall under paragraph 4.1). In addition,

the FAA h as authorize d the use of VDL M0/A for CPDLC -DCL application. Operators

10/3/17 AC 90 -117

can use the VDL Mode 2 subnetwork or may par ticipate in CPDLC -DCL using

VDL M0/A with no additional responsibilities. If the operator ’s aircraft is equipped with

a properly -functioning VDL M2 radio before start ing the flight or dispatching , the FAA

accept s the use of VDL M0/A en route when VDL M2 communications are lost .

4.6.1 Initial CSP Qualification . A CSP planning to offer an alternate subnetwork for data link

communications in the United States should contact the FAA Data Communications

Program Office . The CSP need s to provide substantiating information to demonstrate

their subnetwork satisfies the re quirements allocated t o the CSP and will need to enter

into an agreement with the FAA on the sharing of data, notification of outages, security

of communication, and other detailed characteristics. For further information refer to the

Data Communication s Network Services (D CNS ) Alternative Media Description .

4.6.2 Alternate Subnetworks . The FAA allows operators to select an alternate subnetwork

other than VDL M2, provided the subnetwork satisfies the required performance

allocation and the operator/CSP enters into an agreement to ensure the performance is achieved and maintained. The FAA identifies accepted alternate subnetworks by listing on the Performance- Based Flight Systems Branch (AFS -470) Data Communications

(DataComm)

website . CSPs will be notified of changes to this list. CSPs must comply

with the alternate media performance specifications for VD L Mode 2 shown in Table 4- 9,

Data Communications Network Services (DCNS) Performance Baseline.

10/3/17 AC 90 -117

Table 4 -9. Data Communication s Network Services (DCNS) Performance Basel ine

Performance Metric System Requirements

Packet Error Rate (Network Service) 10(-5)

Availability – Reliability, Maintainability,

and Availability (Network Service) 0.9999

Mean Time Between Outages (MTBO) –

Reliability, Maintainability, and Availability

(Network Service) 1,344 Hours

Network Service Restoral Time – Reliability,

Maintainability, and Availability 30 Seconds *

En Route Capacity 0.0010 bps per km3

One-Way Latency at 95% (uplink or downlink) < 10 sec

One-Way Latency at 99% (uplink or downlink) < 45 sec

*Reliability, maintainability, and a vailability restoral time applies except for catastrophic

processor fail ures and force major events, in which case the maximum restoration time must be

within 3 minutes.

4.6.3 Operator Agreement with CSP . Operators using an alternate subnetwork qualified by the

FAA have similar responsibilities as when using data link communications for oceanic

and remote continental operations. The CSP must meet the specifications in

paragraph s 4.6.3.1 through 4.6.3.3 .

4.6.3.1 Transfer Delay.

1. The CSP uplink transfer delay m ust be less than or equal to

10 seconds for 95 percent of all ATSU data messages.

2. The CSP downlink transfer delay must be less than or equal to 10 seconds for 95 percent of all ATSU data messages .

3. The CSP uplink transfer delay m ust be less than or equal to

45 seconds for 99 percent of all ATSU data messages .

4. The CSP downlink transfer delay m ust be less than or equal to

45 seconds for 99 percent of all ATSU data me ssages.

4.6.3.2 Data Integrity . The Packet Error Rate at the CSP Network Service Delivery

Point (SDP) must be less than 1x10

-5. The packet error rate is the number of

incorrectly received data packets divided by t he number of received packets.

A packet is declared incorrectly received if at least one bit is erroneous or if it

is delivered to an incorrect recipient. This metric excludes packets lost in transmission due to connection failure or excessive latency, as those are accounted by other metrics.

10/3/17 AC 90 -117

4.6.3.3 Reliability, Maintainability, and Availability. The reliability,

maintainability , and availability performance requirements presented in this

section apply to the specific CSP subnetwork seeking qualification and should not take into account the availability of additional subnetworks in order to achieve the required performance levels. A network service thread includes all equipment between the CSP SDP and aircraft users, excluding any aircraft

components. This would include the relevant emitting or receiving ground station antenna(s) as well as transmitting/receiving the necessary radio

frequency ( RF) signal levels across the entire ordered service v olume

in question. Signal levels need to account for terrain impacts, as applicable to

the service volume in question. For the purposes of availability, utilization of

diverse ground station sites and other means of redundancy are included to provide the required level of availability for the ordered service volume.

1. The service availability for each network service thread must be

at least 0.9999.

2. The minimum calculated service availability must be measured over the latest 12 -month period. Availability is calculated

as follows:

•

Available Time : Total time during the latest 12 -month period the

service was under contract.

• Total Outage Time: T he total unapproved service interruption

or degradation time during the Available Time. It includes any unapproved degradation in which the service failed to meet all performance requirements of this specification. It includes any length of time exceeding the duration of a FAA-approved interruption

or degradation.

4.7 CSP Monitoring. For oceanic and remote continental operations and for the use of alternate subnetworks for U.S. data communications, the operator must be aware of their CSP performan ce. The operator and CSP agreement should address performance

monitoring and the performance data as necessary to remain in compliance.

4.7.1 U.S. Domestic Data Communications . If the CSP performance fails to satisfy the

allocated requirements, the FAA will notify the CSP and operators . In this case,

the alternate subnetwork authorization for operations is suspended and the operator

should not file or use the associated perf ormance standard (if prescribed) until the FAA

indicates the alternate subnetwork performance is compliant.

10/3/17 AC 90 -117

CHAPTER 5. OPERATIONAL USE OF DATA LINK COMMUNICATI ONS

5.1 Operational Use.

5.1.1 Application Process . Operators must contact their principal operations inspector ( POI)

to begin the application process for an OpSpec/MSpec/LOA A056 authorization.

A compliance guide is available at: https://www.faa.gov/about/office_org/headquarters

_offices/avs/offices/afx/afs/afs400/afs470/datacomm /. This guide expedites the

compliance process as it condenses into one location the information required for

data link operations.

5.1.2 Minimum Equipment List (MEL) and Master Minimum Equipment List (MMEL) .

MEL s and MMELs must include any revisions necessary f or data link communication

operations. These provisions must be approved by the FAA . Operators must specify the

required dispatch conditions. A sample MEL is provided in Appendix B, Data Link

Communications Minimum Equipment List ( MEL ) and Master Minimum Equipment List

(MMEL ) Provisions .

5.1.2.1 MEL procedures, limitations , and requirements should consider the system

as a whole and also may consider subf unctions and other system

interdependencies. Communications Mana gement Unit ( CMU ) inoperative

may render all Controller -Pilot Data Link Communication ( CPDLC ) virtually

inoperative, while loss of Very High Frequency (VHF) Data Link ( VDL )

Mode 2 ( M2) may render the system una cceptable for KUSA domestic

but may be acceptable for en route oceanic operations provided satellite

communications ( SATCOM ) or alternate media is available and m eets

performance requirements. Other systems with inter -relations such as Global

Positioning System ( GPS) function inoperative may not affec t CPDLC

operations, but depending on airplane design may affect Future Air Navigation Systems (FANS ) Automatic Dependent Surveillance- Contract

(ADS -C) operations. MMEL and Operator MELs should consider all

functions and system relationships to the greatest extent possible.

5.1.2.2 For operations where communication equipment is required to meet a Required Communication Performance ( RCP )/Required Surveillance

Performance ( RSP) specification, the perf ormance must be included in

the MEL.

5.1.3 Flight Plans . Dispatchers and pilots intending to conduct operations using data link

communication must file an accurate flight plan (see Appendix D, Flight Planning ).

Air Traffic Service Unit (ATSU) automation relies on correct fligh t plan codes to

determine aircraft and operator data communication eligibility for various services (e.g., reduced separation). If operators defer data link equipment before flight, a new

flight plan must be filed reflectin g the revised capability codes. T he flight plan must

always accurately reflect the aircraft’s current capabilities .

10/3/17 AC 90 -117

Note: Part 91 operators filing “J” codes for U.S. domestic data link services must have

a data link authorization to file J5 –J7 in oceanic and remote continental airspace

(see Appendix D ).

5.2 Data Link Operational Guidance. Pilots must be proficient with the equipment and

procedures used for data link communication. Training must be based on operati ng

guides from the manufacturer or approved oper ational procedures for operators with a

FAA certificate . The NAS Data Communication s Guide is available to provide general

data communication procedure guidance in the United States but is not a substitute for

Original Equipment Manufacturer ( OEM )/Airplane Flight Manual ( AFM ) procedures.

For international operations, operators should reference International Civil Aviation

Organization (ICAO) Doc 10037 , Global Operational Data Link (GOLD) Manual ,

ICAO Doc 9869 , Performance- Based Communication and Surveillance (PBCS ) Manual ,

and state Aeronautical Information Publication s (AIP).

5.2.1 Crew Resource Management (CRM) . When operating aircraft with more than one pilot,

the pilot flying and pilot monitoring (not flying) should individually review each CPDLC

uplink message (UM) prior to responding to and/or executing any clearance and

individually review each CPDLC downlink message (DM) prior to transmission. Reading

a message individually is a key element to ensuring that each pilot does not infer any

preconceived intent different from what is intended or appropriate. Reading the message

aloud would bias the other pilot and could lead t o the error of “ reading ” what was read

aloud as opposed to what was actually displayed.

5.2.1.1 UMs. Some UM s, such as complex or conditional clearances, require special

attention to prevent the pilot from responding to a clearance with ROGER (DM3)/ WILCO (DM0) but not complying with that clearance. To minimize

errors, when responding to a clearance with ROGER (DM3) /WILCO (DM0),

each pilot should read the UM individually (silently) before initiating a

discussion about whether and how to act on the message.

5.2.1.2 DMs. In a similar manner, each pilot should individually review CPDLC DM s

before the message is sent.

5.3 Logon /Notification .

5.3.1 Departing U.S. Domestic Airports . The logon/notification should be approximately

30 minutes prior to proposed departure time. Pilots should maintain KUSA until logged off/disconnected by air traffic control ( ATC ). If leaving U.S. domestic airspace,

the automatic transfer from KUSA to the next data authority (NDA) may not be possible.

In such cases, the pilot must terminate the CPDLC connection(s) and then initiate a

logon/notification to prompt the new Current Data Authority (CDA) to establish a

CPDLC connection.

Note: Intermittent NO COMM annunciations may occur and do not necessarily

mean the ATC connection is lost. Pilots should delay logging off/ disconnecting to

allow the annunciat ion to end as the system may re establish the connection.

10/3/17 AC 90 -117

Logging off/d isconnecting and logging back on/notifying will cause the ATC

connection to end and may block future connections.

5.3.2 Blocked List . In rare instances for security and safety reasons, an aircraft may be blocked

from any logon /notification attempt until it is manually removed by the Flight Data

Communication s Specialist (FDCS). This occurs automatically via the system or

manually by the FDCS. The following reasons may cause an aircraft to be blocked from

logon/notification :

1. Number of logon/notification attempts received from an aircraft exceeds the

maximum allowable number within the adapted time period. This is to prevent denial of service attacks against the data link communication service.

2. Suspected duplicate aircraft registration. This is to prevent messages which are addressed by aircraft registration from going to the wrong aircraft.

5.3.2.1 Pilot Action. The pilot experiencing a blocked logon/notification should

either contact clearance delivery or their Aeronautical Operational Control (AOC) to resolve the issue.

5.3.3 Outside Data Link Airspace. The pilot should initiate a logon /notification

10 to 25 minutes prior to entry into airspace where data link communication services

are provided or prior to entering oceanic and remote continental airspace .

Note: Departing from a foreign airport close to or within oceanic and remote

continental airspace may require t he logon/notification to be initiated prior to

departure.

5.3.4 Required Data for Logon /Notification . To perform an initial logon/notification request,

the pilot enters the four character ICAO identifier of the ATSU and enters/verifies the

following flight -speci fic information:

1. Aircraft identification (same as item 7 of the flight plan);

2. Aircraft registration , if applicable, and/or aircraft address (same as item 18 of

the flight plan); and

3. Departure and destination airports, when requi red (same as items 13 and 16

of the flight plan).

Note 1: When the aircraft identification inc ludes a numeric component,

this component must exactly match what is listed on the flight plan.

In other words, “ABC3” does not match “ABC003.”

Note 2: While the ATSU identifier is only four characters, Aer onautical

Telecommunication s Network ( ATN ) Baseline 1 (B1) is capable of supporting up

to eight characters.

Note 3: If applicable, ensure ADS -C is on or armed prior to logon/notification .

10/3/17 AC 90 -117

5.3.5 Data Must Match Flight Plan . To avoid an automatic reje ction of the logon/notification

request, the pilot must ensure the flight -specific information entered into the aircraft

system is the same as the corresponding details filed in the flight plan.

5.3.6 Possible Reasons for Failed Logon/Notification . The following are possible reas ons for

receiving an indication of logon/notification failure :

1. Logon /Notification information does not exactly match flight plan

(e.g., incorrect tail number and/or call sign/flight ID) ;

2. Ground or air system anomaly ;

3. Data corruption;

4. Suspected duplicate ai rcraft registration ;

5. Aircraft intentionally blocked from logging on /notifying (i.e., on blocked l ist

due to problem reports with the aircraft) ; and/or

6. There is no flight plan for the flight or the flight plan did not transfer from

one ATSU to the next .

5.3.7 Failure of Data Link Communication Connection. When failure of a data link

communication connection is detected (downlink message fails to send) , the pilot should

terminate the connection and then initiate a new logon /notification with the current

ATSU. If another failure occurs, revert to voice communication.

5.3.8 Logon /Notification Response . The logon/notification response message provides

information to the aircraft system concerning whether:

1. The logon/notification request was successful (e.g. , could be correlated with a

flight plan); or

2. The logon/notification request was unsuccessful (e.g., could not be correlated

with a flight plan).

5.4 En Route. Normally, response to CPDLC messages should be via CPDLC and response

to a voice message should be via voice. Howeve r, if a CPDLC message is unclear or

conflicting, always clarify with voice and then close the CPDLC dialog .

5.4.1 Contact or Monitor Message . A CONTACT (UM117) or MONITOR (UM120) message

instructs the pilot to change to the specified frequency and may include a position or time

for when to change to the new frequency. Use of a CONTACT or MONITOR message is as follows:

1. When a MONITOR (UM120) message is received, the pilot should change to

the specified frequency upon receipt of the instruction or at the specified time or position. The pilot should not establish voice contact on the frequency.

10/3/17 AC 90 -117

2. When a CONTACT (UM117) message is received, the pilot should change to

the specifi ed frequency upon receipt of the instruct ion or at the specified time

or position, and establish voice contact on the frequency.

5.4.2 Waypoint Sequencing . The pilot should ensure waypoints are sequenced correctly. If an

aircraft passes abeam a waypoint by a dis tance greater than the aircraft f light

management s ystem ( FMS ) waypoint automatic sequencing parameter, the pilot should

manually sequence the waypoints in the FMS . If the pilot does not sequence the

waypoints, incorrect information will be contained in AD S-C repo rts and CPDLC

position reports; the next waypoint in these reports will actually be the waypoint that the

aircraft has already passed. This may result in a timing error or out of conformance

indication on the Air Navigation Services Providers ( ANSP ) ground system .

5.4.3 Multi- Part Messages . If pilots are unable to comply with a ny portion of a multi- part

message, “ UNABLE ” (DM1) the entire message. Additionally, pilots should avoid

sending multiple requests to the ATSU in a single message.

5.4.4 CPDLC Connection Failure . If a CPDLC dialogue is interrupted by a data link service

failure, expect the controller to recommence the entire dialogue by voice communication.

When the controller recognizes a failure of the CPDLC connection, the controller will instruct the pilot to terminate the connection and t hen initiate another logon /notification .

See Table 5- 1, CPDLC Connection Failure Responses, for the voice phraseology in

response to a connection failure .

Table 5- 1. CPDLC Connection Failure Responses

Controller/Pilot Response

Controller (or radio operator) CPDLC FAILURE.

DISCONNECT CPDLC THEN LOGON TO

[facility designation]

Pilot DISCONNECTING CPDLC WITH

[facility designation]. LOGGING ON TO

[facility designation]

Note: Additional voice phraseology is available in Appendix E, Voice

Phraseology .

5.5 Voice Monitoring. Pilots must continuously monitor VHF or high frequency (HF)

as appropriate and/or maintain a Selective- Calling System (SELCAL) watch.

5.5.1 Pilot Response . As with voice communication, pilots should respond as soon as possible

to all data link communication messages (e.g. , ROGER (DM3)/WILCO (DM0),

UNABLE (DM1) , or STANDBY (DM2 )). If more time is needed to make a decision and

respond, select standby (“STBY” ).

10/3/17 AC 90 -117

5.6 Free Text Messages . Free text messages should only be used when a standard message

element does not exist or is inadequate. When sending a free text message, use standard

ATSU phraseology and avoid using non- standard abbreviations. (See Appendix E .)

Note 1: For FANS 1/A implementations, the pilot cannot respond to the free text

message element with ROGER (DM3)/ WILCO (DM0) , UNABLE (DM1) , or

STANDBY (DM2).

Note 2: When the controller uses free text to ask the crew affirmative/negative

questions, the pilot can only respond with ROGER (DM3)/WILCO (DM0), which

means they have read and understood the message, but does not answer the

question affirmatively. In these cases, the pilot should respond to the question

with a separate message ( see Appendix E).

5.7 Data L ink Communication Failures. The pilot must notify the ATSU as soon as

practical of any indications of degraded performance resulting from a failure or loss of connectivity in accordance with 1 4 CFR part 91, § 91.187

. For example, reportable

events include :

1. When operating outside of VHF coverage area and the SATCOM data link communication system fails; and

2. When operating in airspace where ATSU surveillance services are provided and the VHF data link communication system fails.

Note: Timely notification is appropriate to ensure the ATSU has time to assess

the situation and apply a revised separation standard, if necessary.

5.7.1 Failure of Automatic Transfer . If an automatic transfer of the CPDLC connection does

not occur at the boundary (CDA to NDA) , the pilot should contact the transferring ATSU

by sending a CPDLC TRANSFER FAILURE (DM 67) message or voice equivalent,

advising them the transfer has not occurred. If this does not resolve the situation, the pilot

should logoff/ disconnect and logon/notify the NDA. Revert to voice if still unable to

logon/notify NDA.

5.7.2 Actions and Phraseology for Data Link Communication Failure . In the event of an

aircraft data link communication system failure, the pilot should revert to voice and

notify the ATSU of the situatio n. For example, for a CPDLC failure, the pilot should use

the voice phraseology , “CPDLC failure, continuing on voice ,” as shown in Table E-1,

Voice Phraseology R elated to Controller -Pilot Data Link Communication (CPDLC )

From Pilot. The pilot continues to use voice until the functionality o f the aircraft system

can be reestablished.

5.8 ADS -C. Normally, the pilot should leave ADS -C armed for the entire flight. Howe ver,

in airspace where ADS -C is available, if the pilot switch es ADS -C off for any reason,

or they receive indication of avionics failur e leading to loss of ADS -C, the pilot should

advise ATC an d follow alternative procedures.

10/3/17 AC 90 -117

5.8.1 Airspace W here ADS -C Is Not Available . In airspace wh ere ADS -C is not available,

the pilot may sw itch ADS -C off to cancel inadvertent ADS -C connections. In such cases,

the pilot should ensure the ADS -C is armed when reentering airspace where ADS -C is

again available.

5.8.2 Emergencies . The pilot may activate the A DS-C emergency mode, which changes all

existing ADS -C periodic contracts from normal mode to emergency mode and creates

emergency mode ADS -C periodic contracts on any ADS -C connections that do not have

a perio dic contract already in place. The pilot may also activate ADS -C emergency mode

by sen ding a “MAYDAY MAYDAY MAYDAY ” (DM56) or “PAN PAN PAN” (DM55)

CPDLC message. ADS -C emergency mode may be deactivat ed by the ATSU or by the

pilot sending a “CANCEL EMERGENCY” (DM58) CPDLC message. In emergencies,

pilots may revert to voice communication when able.

5.9 Exiting CPDLC and ADS -C Areas. The ATSU should automatically logoff/ disconnect

data authority approximately 15 minutes after exiting CPDLC and/or ADS -C areas.

After 15 minutes, if aircraft equipment permits, the pilot should ensure there are no active

CPDLC or ADS -C connections. Ensuring connections are not active eliminates the

possibility of inadvertent or inappropriate use of the connections.

5.9.1 Contact Current ATSU . The pilot should contact the current ATSU unit prior to the

manual termination of an y ADS -C contract. This applies even when outside the

applicable ATSU and the pilot logs off/disconnects ADS -C because it did not

logoff/ disconnect 15 minutes after leaving ADS -C airspace.

5.9.2 Connection Termination Failed. In the event the connect ion termination has failed,

the pilot should contact the ATSU via voice or any other appropriate means.

5.10 Logoff/ Disconnect . Prior to logoff/ disconnect , the pilot should ensure there are

no unresolved or open messages. The pilot will logoff/disconnect and confirm CPDLC

connection is terminated and continue with voice communication.

Note: Pilots should wait at least 10 minutes after landing before initiating a

CPDLC -Departure Clearance ( DCL ) logon /notification to ensure En Route

Automation Modernization ( ERAM ) and Tower Data Li nk Services ( TDLS ) have

enough time to clear previous flight information.

5.10.1 U.S. Domestic Logoff/ Disconnect . Logoff /disconnect s hould automatically occur

approximately 5 minutes after departure for DCL services . Do not logoff /disconnect until

ATC terminates the session . If proceeding to international or oceanic and remote

continental airspace and CPDLC services are not terminated, then manually

logoff/disconnect prior to a new logon/ notification .

Note: When KUSA is active as the domestic U.S. single data authority, CPDLC

services will not automatically terminate after departure. Aircraft leaving

U.S. airspace must logon /notify the next appropriate NDA.

10/3/17 AC 90 -117

5.10.2 International and Oceanic and Remote Continental Logoff /Disconnect . The ATSU should

automatically logoff/ disconnect data authority approximately 15 minutes after ex iting

CPDLC and/or ADS -C areas.

Note: For transitions between data link communication systems (i.e. , FANS

to ATN), f ollow OEM procedures for logon/ notification/logoff/ disconnect

requirements spe cific to your avionics system.

10/3/17 AC 90 -117

CHAPTER 6. PERFORMANCE MONITORI NG

6.1 Performance Monitoring. With the implementation of performance based systems,

monitoring of those systems ensure s compliance. Monitoring provide s a higher level of

confidence the operational system will cont inue to meet the Required Communication

Performance ( RCP )/Required Surveillance Performance ( RSP) specification. Operators

should incorporate a performance monitoring process and must participate in

performance monitoring which includes repo rting and addre ssing problems. The goal of

monitoring data link communication performance is to:

• Maintain safe and efficient operations;

• Determine continued compliance and interoperability ;

• Investigate problems; and

• Share lessons learned.

Note: There are no established RCP/RSP standards in U.S. domestic airspace as

of the publication date of this AC. As Controller -Pilot Data Link Communicatio n

(CPDLC) is introduced into en route operations for U.S. domestic a irspace,

RCP standards will be published.

6.2 Oceanic and Remote Continental Airspace.

6.2.1 FAA Data Collection . The FAA , along with other Air Traffic Service Unit s (ATSU) , has

been monitoring CPDLC a nd Automatic Dependent Surveillance- Contract (ADS -C)

transactions since 2009. Analysis of Actual Communication s Performance ( ACP) for the

CPDLC transactions and Actual Surveillance Performance ( ASP) for the ADS -C

downlink messages (DM) are accomplished on a semi -annual basis with an emphasis on

the nominal continuity (95 percent ) requirements associated with safety .

6.2.2 RCP Performance Analysis . Data analysis of ACP, including the Actual Communication

Technical Performance (AC TP), is compared against RCP standards (see Tables 2-4

through 2-9) to de termine whether the C PDLC performance is adequate.

6.2.3 RSP Performance Analysis . ASP is compared against RSP standards ( see Tables 2-10

through 2-15) to determine whether surveillance performance is adequate. ASP analysis

is based on the calculation of delivery time of the ADS -C periodic and event reports

between the aircraft and the ATSU ground system.

6.2.4 Evaluating Operational and Nominal Transaction Times . ACP and ASP are evaluated

using operational (99.9 percent ) and nominal (95 percent ) continuity criteria . Observed

ACP and ASP must meet or exceed the nominal 9 5 percent continuity requirements .

Note 1: If ACP/ASP does not meet the nominal continuity, the operator will be

notified and should not continue data link operati ons at the associated

performance level until the issue is resolved (see paragraphs 6.4 and 6.5 ).

10/3/17 AC 90 -117

Note 2: If ACP /ASP does not meet the operational continuity 99.9 percent ,

the operator is notified to investigate and initiate corrective action . The nominal

performance 95 percent is still sufficient for data link communication

performance.

6.3 Performance Website. Operators may obtain a Pass/Fail/insufficient data monitoring

performance report for their aircraft from the FAA Performance -based Communication

and Surveillance (PBCS) Monitoring website .

6.4 Substandard Performance. Operators must address substandard performance whether

the source of that report is from the operator’s own monitoring process, Communication

Service Provider ( CSP), FAA, or a foreign authority . Operators can view aggregate

performance observed within FAA oceanic airspace from the PBCS monitoring website in the above paragraph. If the result of the report is “Fail ,” the operator should follow the

directions on the website to request further details and a corrective action plan. With a

“Fail” report , operato rs may continue to operate at a less stringent performance level

(i.e., RCP 240 to RCP 400) provided they file the appropriate performance flight plan

designator.

6.5 Corrective Aircraft Action. The operator may return to the performance stated in their

statem ent of compliance ( SOC ) provided the corrective action plan is completed.

6.6 Data Link Performance Eligibility. As stated in paragraph 3.3.5

, RCP and RSP

performance monitoring data should be included to quanti fy data link eligibility.

If performance monitoring data is insufficient , then the SOC will be the initial basis

for compliance with continued monitoring.

6.7 Procedures to Report Problems. The operator should establish procedures to report

problems to the regional PB CS monitoring entities identified in Aeronautical Information

Publication s (AIP) (or eq uivalent publications) associated with the route of flight on

which the problem occurred ( see Chapter 8, Reports ).

6.8 Performance Monitoring in U.S. Domestic Airspace. Reserved .

10/3/17 AC 90 -117

CHAPTER 7. TRAINING

7.1 Training Documentation.

7.1.1 Part 91 Operator Training . Part 91 operators must be proficient with the procedures and

operations associated with the use of data link communication systems in accordance

with their Airplane Flight Manual (AFM) and AFM Supplement if applicable. Part 91

operators should be knowledgeable with the procedures and operations as shown in paragraphs

7.4 and 7.5 .

7.1.2 Parts 91 Subpart K (Part 91K), 121, 125, and 135 Operator Training . Part 91K, 121, 125,

and 135 operators should have a training p rogram addressing the operational practices,

procedures , and training items related to data link communication operations (e.g., initial,

upgrade, or recurrent training for pilots, operational control personnel, and maintenance personnel). If criteria for training or checking are other than as specified in this AC,

the criteria may be found in Flight Standardization Board (FSB) reports applicable to a

particular aircraft type.

Note: A separate training program is not required if data link communication

training is integrated in the current training program. However, the applicant must identify the training elements from this AC within the existing training program.

7.2 Objectives. Operators should include the following objectives to ensure appropriate pilot

data link communications qualification:

• Provide necessary pilot knowledge of data link performance -based communication

and surveillance concepts, systems, procedures , and ski lls to properly respond to

data link communication clearances and advisories; and

• Identify human factor issues specific to pilot operation and interaction with the

communication software, hardware, and operating environment (e.g., head- down

time, situational awareness, or loss of pilot response time in the Required

Communication Performance ( RCP ) specification).

7.3 Ground and Flight Training.

7.3.1 Pilot Knowledge/Training . Parts 91K, 121, 125, and 135 operators should maintain

training syllabi (e.g., initial, upgrade, or recurrent) and other appropriate materials

including operational practices and proce dures. Training for other personnel must be

included where appropriate (e.g., operational control personnel or maintenance).

7.3.2 Pilot Training . Parts 91K, 121, 125, and 135 operators should ensure their process

contains training for pilots on equipment requir ements, normal and non- normal

operations and procedures, and limits of their data link communication capability. Pilots must receive data communications training specific to the avionics suite they will

be operating. A common type rating does not guarantee the pilot has received training on the data communications equipment installed on a particular aircraft.

10/3/17 AC 90 -117

7.3.3 Regulatory Basis . All training must be in accordance with the following where

applicable:

1. Part 91 K:

• § 91.1073 , Training P rogram: General.

• § 91.1081 , Crewmember Training R equirements.

• § 91.1111 , Maintenance T raining.

2. Part 121:

• § 121.375 , Maintenance and Preventive Maintenance Training P rogram.

• § 121.401 , Training P rogram: General.

3. Part 135:

• § 135.323 , Training P rogram: General.

• § 135.329 , Crewmember Training R equirements.

• § 135.433 , Maintenance and P reventive M aintenance T raining P rogram.

7.4 Pilot Knowledge Subject Areas. The minimum following subjects should be addressed

in an approved curriculum of data link communications academic training during the

initial introduction of data link communication systems:

1. Normal pilot response to data link communication messages to include :

ROGER ( downlink message ( DM) 3)/WILCO (DM0), UNABLE (DM1),

or STANDBY (DM2) of a data link communication message;

2. Message elements in the message set used in each environment ( e.g., ground,

oceanic, en route) i ncluding terms, abbreviations, and conventions ;

3. RCP/ Required Surveillance Performance ( RSP) specifications and their

performance requirements;

4. Data link communication terminology (e.g., Controller -Pilot Data Link

Communicatio n (CPDLC ) and Automatic Dependent Surveillance- Contract

(ADS -C) reporting contracts);

5. Chart depictions of data link communication services ;

6. Implementation of reduced separation with associated data commu nication

system requirements to comply with RCP 240 and RSP 180 or other possible

performance requirements associated with their routes;

7. Data link communica tions system theory (relevant to operational use);

8. Operations involving data link communication services;

9. Nominal and unacceptable performance;

10. Normal and non- normal use;

11. Data link communication events and reporting ( see Chapter 8 , Reports );

10/3/17 AC 90 -117

12. AFM and AFM Supplement limitations;

13. Crew Resource Management (CRM) of independent message verification,

discussion, and action ( see paragraph 5.2.1 );

14. Minimum e quipment l ist (MEL), deferrable items , and procedures;

15. Human factors specific to the operating environment and operation of installed communication equipment ; and

16. Proper use of flight plan designators for data link operations in U.S. domestic

airspace and , if applicable , in oceanic and remote continental airspace.

Note: For subsequent ground training, only the new, revised, or emphasized items

need be addressed.

7.5 Pilot Procedural Training Items. As a minimum, p rocedural training should include:

1. Proper use of data link communication controls, procedures, and limitations .

2. Logon /notification procedures and reestablishing system operation after loss

of network logon/notification .

3. Display features .

4. Weather deviations, offsets , and waypoint sequencing .

5. Advisories and annunciation.

6. Timely and correct responses to data link communication failures .

7. Recognition of data link communications system failures and data link communication issues unique to the air carrier or operator.

8. Appropriate interaction with the Air Traffic Service Unit (ATSU) following

data link communication messages that are not acceptable.

9. CRM. Independent message verification, discussion, and action

(see paragraph 5.2.1) .

10. Understanding, a ccepting, receiving, rejecting, or canceling messages .

11. Storing and retrieving messages .

12. Loading messages into appropriate controls/displays for use (e.g., f light

management s ystem (FMS)) formulating and sending messages .

13. Departures and departure t ransitions are not included in the loadable r oute

uplink and must be manually entered by the pilo t into the FMS when provided

in the Departure Clearance ( DCL ). Refer to the

NAS Data Communication s

Guide .

14. Loading message requests from the FMS (e. g., flight plan waypoints into

data link communication for transmission , if applicable) .

15. Managing the communications systems .

16. Establishing and terminating system operation .

10/3/17 AC 90 -117

17. Switching use of Radio Frequency (RF) media (if this i s a pilot -controllable

featur e).

18. Items particular to an air carrier’s implementation or the uniqueness of its

aircraf t capability and/or procedures .

19. Applicable message sets, expected transmission times, failure annunciations, constraints, and limitations .

20. CRM in responding to data link communication exchanges .

21. Data link communication modes of operation.

22. Normal and non- normal pilot operating procedures.

23. Conditional clearances and the adherence to certain conditions or restrictions such as changing a flight level based on a time or pl ace.

7.5.1 Credit for Training . Operators may receive credit for existing data link communications

training already approved in a different application. For example, an operator may

receive credit for training based on previous use of data link communication services,

such as on different routes, for a different type of operation, or training conducted by another operator (except for part 121 or 135) , training center, or manufacturer.

The principal operations inspector ( POI) will determine whether and how much cr edit

an operator should receive, considering whether the training is used in another

FAA -approved application and whether the operator has demonstrated the training is

relevant to the new application.

7.5.2 Pilot Currency . Once pilots have completed initial data link communication training ,

pilot currency programs/training should include data link communication elements.

7.6 Dispatcher Training . An aircraft dispatcher, flight follower , or other operational control

personnel should not be assigned to duty unless he/she has demonstrated satisfactory

data link communication knowledge to the operator . Training should include:

• Proper use of flight plan designators (see Appendix D, Flight Planning);

• ATSU separation criteria and procedures;

• MEL remarks or exceptions based on data link communications;

• Procedures for transitioning to voice communication and other contingency

procedures related to the operation in the event of abnormal behavior of the da ta link

communication services;

• Coordination with the ATSU related to or following a special data link

communication exceptional event; and

• Contingency procedures to transition to a different separation standard when data link

communication servi ces fail.

10/3/17 AC 90 -117

7.7 Maintenance Training. Operator s should ensure all maintenance personnel receive

training on their airplane’s data link communication equipment. Operators unsure of

required maintenance procedures for data link communication- related equipment should

contact their aircraft manufacturer field service representatives .

10/3/17 AC 90 -117

CHAPTER 8. REPORTS

8.1 Introduction. Operators and manufacturers must develop reporting procedures to ensure

effective identification, tracking , and followup of data link-related events. P rocedures

should provide the following to the R egional M onitoring A gency (RMA).

• Proper assess ment of data link communication events; and

• Specific data link communication events as necessary .

8.2 Common Reasons to Report. Common reasons for submitting a problem report are:

1. Failure to log on /notify ,

2. Logoff/d isconnect,

3. Corrupted messages, and

4. Excessive delay.

8.3 Oceanic and Remote Continental Problem Reporting. For Future Air Navigation

Systems (FANS ) 1/A(+) p roblem reporting i n oceanic and remote continental airspace,

notify the FANS Central Reporting Agency (CRA) at http://www.fans -cra.com/ . This site

is maintained by Airways New Zealand as a service to the global FANS community and

includes the:

• International Civil Aviation Organization (ICAO) North Atlantic (NAT) Data Link

Monitoring Agency (DLMA),

• Informal South Pacific ATS Coordinating Group (ISPACG) CRA,

• Informal Pacific ATC Coordinating Group (IPACG) CRA, and

• FANS Inter operability Team (FIT) Asia CRA.

8.4 U.S. Domestic Airspace Problem Reporting . For data link communication problems

in U.S. domestic airspace , an Operational Problem Report (OPR) should be filed with

the FAA by downloading the Data Comm Operational Problem Report Ticket .

The completed information should be faxed or emailed as shown on the form. Harris

Corporation is contracted by the FAA to pr ocess problem reports.

8.5 Problem R eporting P rocess. The following is the problem reporting process:

1. Operator submits problem report.

2. RMA :

• Gathers information as necessary,

• Performs an analysis ,

10/3/17 AC 90 -117

• Collaborates with subject matter experts (i.e. , Original Equipme nt Manufacturers

(OEM)), and

• Determines appropriate solutions .

3. Operator is notified of the results .

10/3/17 AC 90 -117

Appendix A

AP

PENDIX A. FOREIGN OPERATORS

A.

1 General. Foreign operators may use data link communications when operating in

U.S. airspace. In order to take advantage of Air Traffic Service Unit ( ATSU)

data communication services, foreign operators must be properly equipped and file the

appropriate flight plan designator codes ( see Chapter 3 , Aircraft Eligibility,

and Appendix D, Flight Plan ning).

A.2 Title 14 CFR Part 129 . The FAA does not approve data link communications

installations, training programs, minimum equipment lists ( MEL ), or maintenance

programs for foreign operators operating non- U.S.-registered aircraft. Such

authorizations are addressed as specified by the S tate of the O perator or State of Registry,

as appropriate. However, since compatibility of data link communications within

U.S. airspace is essential, part 129 operations guidelines for data link communications are

provided by this AC. Compliance with these data link communications provisions ensures both data link communication system and procedural compatibility. The FAA issues authorization to foreign operators for data communications operations in U.S. airspace via operations specification (OpSpec) A003. Outside the United S tates,

in international waters wherein U .S. air traffic (i.e., N ew Y ork and Oakland air route

traffic control centers (ARTCC) ) is tasked by the International Civil Aviation

Organization (ICAO) with traffic separation for all aircraft , the foreign operator needs to

have their Civil Aviation Authority’s ( CAA ) approval for data comm unications.

The FAA does not issue an OpSpec for operations outside the United S tates.

See Appendix

B, Data Link Communications Minimum Equipment List (MEL) and

Master Minimum Equipment List (MMEL) Provisions, for further details on MELs and MMELs when the FAA is the State of Registry of a foreign operator’s aircraft.

More details will be provided in future revisions of the AC as they become available.

A.3 Applicatio n Process. Foreign operators should contact their FAA principal operations

inspector ( POI) to obtain application information for part 129 data link communications

authorization in U.S. airspace. When a foreign operator submits the necessary information to the responsible principal inspector (P I), showing its aircraft are

in compliance, the PI approves data comm unications via OpSpec A003 or an amendment.

Although not mandatory, foreign operators should comply with the provisions of this AC or equivalent provisions specified by the S tate of the Operator or by ICAO.

A.4 Unique Address. An appropriate data link communication system must be installed and

operated on suitable frequencies specified by the ATSU during flight in U.S. airspace if procedures are predicated on its use. A unique and specific address, the ICAO 24- bit

aircraft identification, must be assigned to the airplane and the data link communication must recognize this address. When properly set, the unique address may not be altered, set to a duplicated address, or set to an address that potentially interferes with the ATSU

or data link communication safety functions.

A.5 U.S. Interoperability Requirements. The operator must confirm the interoperability of

their aircraft data link system (interoperability re quirements standards (INTEROP)

designators are described in Table 2-2

, Interoperability Designators and Descriptions).

A-1

10/3/17 AC 90 -117

Appendix A

The data link communication system must be operated in accordance with the

U.S. airspace interoperability requirements , except as provided for by the MEL

provisions acceptable to the State of the Operator.

A.6 Training . Training and procedures for use of data link communication as specified

by ICAO, this AC, or other equivalent criteria acceptabl e to the FAA should be used

when operating in U.S. airspace.

A.7 Unsafe Performance or Conditions. Unsafe performance or conditions related to

data link communication operations which potentia lly could affect continued safe

operations in U.S. airspace (a data link communication event) should be reported to their

International Field Office (IFO) (refer to the FAA’s IFO website ). Operators should also

follow the problem reporting procedures in Chapter 8, Reports .

A.8 U.S. Domestic Airspace. For a summary of U .S. domestic ( Controller -Pilot Data Link

Communication –Departure Clearance (CPDLC -DCL) service and U .S. en route data

communication service) airspace requirements , see Appendix C , Summary of Airspace

Requirements.

A-2

10/3/17 AC 90 -117

Appendix B

APPENDIX B. DATA LINK COMMUNICATIONS MINIMUM EQUIPMENT LI ST

(MEL ) AND MASTER MINIMUM EQUIP MENT LIST ( MMEL ) PROVISIONS

B.1 Inoperative Equipment. Each operator intending to have authority to dispatch an

aircraft with a data link communication system or component temporarily inoperative

must do so in accordance with provisions of a m inimum equipment l ist (MEL).

For U.S. -registered aircraft, MELs are approved for each operator and type aircraft,

within provisions of the FAA Master Minimum Equipment List (MMEL) for that type. When proposed MEL provisions are consistent with the FAA MMEL, principal operat ions inspectors (POI) may approve the MEL. Enhanced features (those above and

beyond the basic data link communication system) may be inoperative, provided the inoperative features do not degrade the system ( e.g., data link communication printers).

Note: Title 14 CFR part 91, § 91.213

does not provide MMEL relief should

equipment fail that is not included in the MMEL/MEL. Also refer to 14 CFR part

121, § 121.628; part 125, § 125.201; part 129, § 129.14; and part 135 ,

§ 135.179 .

Table B -1. Minimum Equipment List Example

B-1

10/3/17 AC 90 -117

Appendix B

Table B -2. Example of a Data Link Communication MMEL Provision

N

ote 1: The provisions and repair category intervals are intended to grant the

operator sufficient relief during the initial stages of the data link communication

implementation. This is intended to promote the installation process, as well as

support the use of a partial system. Both equipment reliability and operational experience will dictate, what, if any, revision to this MMEL relief should be considered after the installation phase is completed.

Note 2: Operators are responsible for entering the number in the “Number

Installed” column of the MEL.

Note 3: Operators are responsible for entering alternate procedures in the MEL

comment sectio n or referencing the location of such procedures in their

manual system.

Note 4: If MMEL has not been updated for Controller- Pilot Data Link

Communicatio n (CPDLC ) equipment for aircraft that are issued a Supplemental

Type Certificate ( STC), the operator is reminded that they must adhere to

§ 91.213. Note 5: Special Condition: The MMEL does not provide relief for inoperative

data communications equipment at this time and is being reviewed at the Aircraft

Evaluation Group (AEG). Should any of the equipment/software fail relative to

data link communications, the data equipment/software must be replaced/repaired before the aircraft can take off according to § 91.213(a).

B-2

10/3/17 AC 90-117

Appendix C

APPENDIX C. SUMMARY OF AIRSPACE REQUIREMENTS

C.1 Summary of Airspace Requirements . (Table C -1, Summary of Airspace

Requirements .) Each Air Traffic Service Unit (ATSU) providing data link services

defines the requirements for their operations ( refer to International Civil Aviation

Organization (ICAO) Doc 4444, Procedures for Air Navigation Services - Air Traffic

Management ; ICAO Doc 7030, Regional Supplementary Procedures; ICAO Doc 10037,

Global Operational Data Link (GOLD) Manual, ICAO Global Guidelines for Data Link

Operations; Aeronautical Information Publications ( AIP); and flight information region

(FIR) specific bulletins for additional information).

Table C-1. Summary of Airspace Requirements

Airspace Service

(Operational

Use) Aircraft Data Link

Communication

System

(Interoperability) ATSU

Provided

Subnetwork Operator -

Provided

Subnetwork Performance

Specification

U.S.

(Domestic) CPDLC -DCL

service FANS 1/A(+) VDL M2 or

VDL M0/A N/A N/A

U.S.

(Domestic) En route data

communication

services FANS 1/A(+) VDL M2 **** VDL M0/A* TBD

Continental

(Domestic) European data

link program ATN B1 VDL M2 N/A N/A

Oceanic and

Remote

Continental Oceanic and remote

continental

23 NM lateral or

along- track

spacing*** FANS 1/A(+)

N/A SATCOM

(Classic Aero, SBB, or

SBD)** RCP 240

RSP 180

Oceanic and

Remote

Continental 50 NM Longitudinal

FANS 1/A(+) N/A SATCOM

(Classic Aero,

SBB, or

SBD)** RCP 240

RSP 180

Oceanic and

Remote

Continental 30 NM Longitudinal FANS 1/A(+) N/A SATCOM

(Classic Aero,

SBB, or

SBD)** RCP 240

RSP 180

Oceanic and

Remote 5 Minute Longitudinal FANS 1/A(+) N/A SATCOM

(Classic Aero,

SBB, or

SBD)** RCP 240

RSP 180

C-1

10/3/17 AC 90- 117

Appendix C

Airspace Service

(Operational

Use) Aircraft Data Link

Communication

System

(Interoperability) ATSU

Provided

Subnetwork Operator -

Provided

Subnetwork Performance

Specification

Oceanic and

Remote

Continental N/A FANS 1/A ADS -C N/A SATCOM

(Classic Aero,

SBB, or

SBD)**

HFDL N/A

Oceanic and

Remote

Continental/

Domestic N/A ACARS VDL M2 or

VDL M0/A SATCOM

(Classic Aero, SBB, or

SBD)**

HFDL N/A

Note: Table C -1 asterisks:

* An approval is required to use VDL M 0/A for U .S. en route data

communications and the operator assumes responsibility for the C ommunication

Service P rovider (CSP) . The allocation of performance requirements to the CSP is

more stringent than the RCP 240 allocation, which is used only to ide ntify the

aircraft allocation. See Chapter 4, Communication Service Providers .

** Aircraft typically use VDL M0/A or VDL M2 when in range of ground radios,

which is also acceptable. However, an aircraft wit h only these subnetworks would

not be eligible for the oceanic and remote continental operations due to coverage

limitations.

*** See ICAO Doc 4444 for more information.

**** Must be tunable (Technical Standard Order (TSO )-C160a or later ,

Very High Frequency (VHF) Digital Link (VDL) Mode 2 Communications

Equipment ) with “push to load” capability into the navigation system whenever

a routing change is received for operations supported by Baseline 2 ( B2) and

Future Air Navigation Systems (FANS ) 1/A(+) data link communication systems.

C-2

10/3/17 AC 90- 117

Appendix C

Table C -2. Sub network Designators

Subnetwork Designator Description of Designator

VDL M0/A Very high frequency data link – Mode 0/A

VDL M2 Very high frequency data link – Mode 2

HFDL High frequency data link

SATCOM (Classic Aero) Inmarsat or MT -SAT – Classic Aero satellite

communications

SATCOM (SBB) Inmarsat – SwiftBroadband satellite

communications

SATCOM (SBD) Iridium – Short burst data satellite

communications

Table C -3. Preferred Original Equipment Manufacturer Annotation

“The FAA has approved the aircraft data li nk system to the criteria in

AC 20-140C for the following data link capabilities:

Interop Designators: FANS 1/A+ (with automation)

ATN B1

B2

ACARS ATS

Subnetworks: VDL M0/A/2

SATCOM (Classic Aero, SBD, SBB)

HFDL

ACARS ATS

Aircraft -Allocated Performance CPDLC : RCP 130, RCP 240, RCP 400

ADS -C: RSP 160, RSP 180, RSP 400

This design approval does not constitute operational authorization.”

C-3

10/3/17 AC 90 -117

Appendix D

APPENDIX D. FLIGHT P LANNING

D.1 Filing Required Communication Performance ( RCP )/Required Surveillance

Performance ( RSP ) Capabilities. When filing RCP/RSP capabilities, operators must

ensure the planned use of associated communication and surveillance capabilities for the

flight will be in accordance with regulations, policies , and procedures in control areas for

the flight, as published by the applicable States in Aeronautical Information Publications (AIP) (or equivalent publications). Operators should ensure the proper information to

denote Performance -based Communication and Surveillance ( PBCS ) capabilities is

included in the International Civil Aviation Organization ( ICAO ) flight plan.

D.1.1 The following are determinations for proper filing:

1. Presence of relevant serviceable equipment on board the aircraft.

2. Equipment and capabilities commensurate with pilot qualifications.

3. When applicable, appropriate authorizations as described in FAA operations specifications (OpSpec)/ management specifications ( MSpec)/ letters of

authorization ( LOA ).

D.2 Regulatory Basis. Flight planning must be in accordance with the following where applicable:

1. Part 91

:

• § 91.169 , IFR F light P lan: Information R equired.

• § 91.173 , ATC Clearance and F light P lan Required.

2. Part 121 :

• § 121.667 , Flight Plan: VFR and IFR: Supplemental O perations.

• § 121.695 , Disposition of Load M anifest, D ispatch R elease, and Flight Plans:

Domestic and Flag O perations.

• § 121.697 , Dispositio n of Load Manifest, Flight R elease, and Flight Plans:

Supplemental Operations.

3. Part 125, § 125.405 , Disposition of Load M anifest, F light R elease, and

Flight P lans.

D.2.1 Flight P lan D escriptors :

• D1and G1 for Automatic Dependent Surveillance- Contract (ADS -C) (Table D-2 ,

Item 10b Flight Plan Descriptors for Surveillance Equipment);

• J1 through J7 for Controller- Pilot Data Link Communicatio n (CPDLC ) (Table D-1 ,

Item 10a Flight Plan COM Descriptors ); and

• P1 and P2 for RCP Performance (Table D -1).

D-1

10/3/17 AC 90 -117

Appendix D

Note 1: Refer t o ICAO Doc 4444 , Procedures for Air Navigation Services –

Air Traffic Management, Appendix 2, for flight plan requirements. Also, refer to

the FAA Flight Planning Information website .

Note 2: The inclusion of PBCS capability in the filed flight plan indicates that

the relevant aircraft equipment comprising the aircraft system is approved and

serviceable, the pilot is appropriately trained and qualified, and the operator holds

applicable authorization to use the equipment for PBCS operations. If these conditions are not met , then PBCS capability should not be included in the

flight plan.

D.3 Example. As a flight plan example , use the following:

If Actual Communications Performance ( ACP ) meets at least RCP 240 at

95 percent and Actual Surveillance Performance ( ASP) meets at least RSP 180 at

95 percent , then the ope rator approved for RCP 240/ RSP 180 may file the

following:

• Field 10: “P2.”

• Field 18: “SUR/RSP180 .”

D.3.1 If ACP does not meet RCP 240 at 95 percent , then the operator may file for RCP 400 by

entering P1 and/or P3 in field 10. If ASP does not meet RSP 180 at 95 percent , then the

operator may file for RS P 400 by entering “SUR/RSP400” in field 18.

D.4 Item 10a Descriptors. In Item 10 a of the flight plan, operators should insert one of the

descriptors , P1- P2, as appropriate, listed in Table D-1

, to identify an aircraft’s RCP

capability .

D-2

10/3/17 AC 90 -117

Appendix D

Table D -1. Item 10a Flight Plan COM Descriptors

Descriptors System

E1 FMC WPR ACARS

E2 D-FIS ACARS

E3 PDC ACARS

J1 CPDLC ATN VDL Mode 2

J2 CPDLC FANS 1/A HFDL

J3 CPDLC FANS 1/A VDL Mode 0/A

J4 CPDLC FANS 1/A VDL Mode 2

J5 CPDLC FANS 1/A SATCOM (I nmarsat )

J6 CPDLC FANS 1/A SATCOM (MTSAT)

J7 CPDLC FANS 1/A SATCO M (Iridium)

P1 CPDLC RCP 400

P2 CPDLC RCP 240

Note: Part 91 operators filing “J” codes for U.S. domestic data link services must have

a data link authorization to file J5 –J7 in oceanic and remote continental airspace.

D.5 Item 10b Descriptors. In Item 10b of the flight plan, operators should insert one of

the descriptors , D1 and G1, as appropriate, listed in Table D -2, to identify an aircraft’s

RSP capability:

Table D -2. Item 10b Flight Plan Descriptors for Surveillance Equipment

Descriptor System

D1 ADS-C with FANS 1/A capabilities

G1 ADS -C with ATN capabilities

D.6 Item 18 RSP Specification. In Item 18 of the flight plan, the aircraft operator should file

the RSP capability by inserting the indicator “ SUR/ ” followed by the appropriate RSP

specification (e.g. , RSP400 or RSP180).

Note: The ATSU unit uses the flight plan information to determine when to apply

particular Air Traffic System Management ( ATM ) operations that are dependent

on the capability and to configure the system (e.g., set timer threshold values) for efficient operation when RCP and/or RSP varies.

D-3

10/3/17 AC 90 -117

Appendix D

D.7 Field 1 8/DAT f or C PDLC or Pre- Departure Clearance ( PDC). The proposed data link

communication “codes” in Field 18/DAT are an optional mechanism for the user to

notify FAA automation to generate a CPDLC or PDC.

• Field 10a (Equipage) used to identify aircraft capabilities .

• F

ield 18 (Other Information) DAT/ codes used to identify flights getting CPDLC

or PDC .

• Need to fill in Field 10a in order to get to Field 18 DAT/.

• F

ield 18 DAT/ c odes will include a primary/secondary hierarchy .

Table D -3. Voice, PDC, DCL

Operators

Using Data Link

Communication

Capability Field 10a Data Link

Communication

for Field 18

DAT/* Comments for FANS

in U.S. Domestic

Operations

Voice only** Not equipped for

ACARS or

FANS; gets voice

only. Default if user is not

getting PDC or FANS. Field 10a may be

optional.

Voice only** Equipped for ACARS and FANS but wants voice only. E3J4J7

Z 1VOICE

Optional. Only needed if

users want to negate default PDC/

CPDLC -DCL value and

use voice only.

Some aircraft are non-ACARS equipped, and 10a is physical equipage. Still get PDC via other means (e.g., gate printer ).

Optional if currently getting PDC. PDC only** Not ACARS equipped but gets PDC via manual means . Z 1PDC

PDC only**

Equipped only for

ACARS /PDC . E3

Z 1PDC Optional if currently

getting PDC.

PDC only** Equipped for ACARS /PDC and

FANS but wants PDC only. E3J4Jx

Z 1PDC Equipped for

ACARS /PDC and

FANS 1/A or 1/A(+),

and possibly other

capabilities (Jx).

D-4

10/3/17 AC 90 -117

Appendix D

Operators

Using Data Link

Communication

Capability Field 10a Data Link

Communication

for Field 18

DAT/* Comments for FANS

in U.S. Domestic

Operations

FANS 1/A &

FANS 1/A+ DCL/PDC only Equipped for

ACARS/PDC and FANS but wants

FANS 1/A only

for CPDLC -DCL . E3J4Jx

Z 1FANS Identifies U .S. domestic

preference for PDC .

FANS 1/A &

FANS 1/A+ DCL/PDC Equipped for ACARS/PDC and FANS with primary/secondary preferences . E3J4Jx

Z 1FANSPDC

Code number shows

priority preference, (e.g., DCL is primary preference; PDC is secondary that will be used if primary i s

unavailable and if

feasible) .

* No spaces in actual DAT/ codes .

** No ICAO flight plan change required if user currently gets PDC and does not want DCL. Current PDC designation will be the default.

D-5

10/3/17 AC 90 -117

Appendix D

Table D -4. DCL and En Route Data L ink Clearances

Operators

Using Data Link

Communication

Capability Field 10a Data Link

Communication

for Field 18

DAT/* Comments for FANS

in U.S. Domestic

Operations

FANS 1/A &

FANS 1/A+

No En Route

UM80 Load

Issues For flights

authorized for

en route data link

with no UM80

load issues. E3J4J

Z 1FANSE2PDC This code is to be used

to obtain CPDLC- DCL

and en route clearances

with aircraft that have

no en route UM80 load

issues; PDC is

seconda ry that will be

used if primary is

unavailable and if

feasible.

FANS 1/A &

FANS 1/A+

With En Route

UM80 Load Issues For flights authorized for en route data link

with UM80 load issues and for PDC service only . E3J4J

Z 1FANSE R2PDC

This code is to be used

to obtain CPDLC- DCL

and en route clearances with aircraft that have en route UM80 load issues; PDC is secondary that will be used if primary is unavailable and if

feasible.

* No spaces in actual DAT/ codes .

D-6

10/3/17 AC 90 -117

Appendix D

Table D -5. PDC Only and En Route Data L ink

Operators

Using Data Link

Communication

Capability Field 10a Data Link

Communication

for Field 18

DAT/* Comments for FANS

in U.S. Domestic

Operations

FANS 1/A &

FANS 1/A+

No En Route

UM80 L oad

Issues For flights

authorized for

en route data link

with no UM80

load issues and

for PDC service

only. E3J4J

Z 1PDCFANSE This code is to be used

to obtain PDC and

CPDLC en route

clearances with aircraft

that have no en route

UM80 load issues from

PDC ONLY airports .

FANS 1/A &

FANS 1/A+

With En Route

UM80 Load Issues For flights

authorized for

en route data link

with UM80 load issues and for PDC service only . E3J4J

Z 1PDC FANSE R This code is to be used

to obtain PDC and CPDLC and en route clearances with aircraft that have en route UM80 load issue s

departing from PDC

ONLY airports .

* No spaces in actual DAT/ codes .

Table D -6. En Route Data L ink Clearances Only

Operators

Using Data Link

Communication

Capability Field 10a Data Link

Communication

for Field 18

DAT/* Comments for FANS

in U.S. Domestic

Operations

FANS 1/A &

FANS 1/A+

No En Route

UM80 L oad

Issues For flights

authorized for

en route data link

with no UM80

load issues . J4

Z FANSE This code is to be used

to obtain PDC and

CPDLC en route

clearances with aircraft

that have no en route

UM80 load issues . (No

Tower DCL or PDC .)

FANS 1/A & FANS 1/A+

With En Route

UM80 L oad

Issues For flights authorized for en route data link

with UM80 load issues. J4

Z FANSE R

This code is to be used

to obtain PDC and CPDLC and en route

clearances with aircraft that have en route UM80 load issues. (No

Tower DCL or PDC .)

* No spaces in actual DAT/ codes .

D-7

10/3/17 AC 90 -117

Appendix E

APPENDIX E. VOICE PHRASEOLOGY

Table E -1. Voice Phraseology R elated to Controller-Pilot Data Link Communication

(CPDLC ) From Pilot

Condition Voice Phraseology

To notify air traffic control ( ATC ) of a

correction to a CPDLC message. ( International

Civil Aviation Organization .

(ICAO) Doc 4444 ) DISREGARD CPDLC (message type)

MESSAGE, BREAK (correct informat ion

or request)

To notify ATC of a single CPDLC message

failure. (ICAO Doc 4444) CPDL C MESSAGE FAILURE (appropriate

information or request)

To notify ATC of an aircraft data link system

or CPDLC connection failure.

(ICAO Doc 4444) CPDLC FAILURE (requests/notifications)

Note: This voice phraseology is included only with the first transmiss ion made for this

reason.

Example: CPDLC FAILURE. CONTINUING

ON VOICE.

To advise ATC the CPDLC connection is

being terminated manually and logon/notification procedure is being initiated

with the next Air Traffic Service Unit ( ATSU). DISCONNECTING CPDLC W ITH (facility

designation). LOGGING ON TO (facility designation)

Note: The facility designation is the ICAO

four-character facility code or facility name.

To advise ATC that a logon /notification

procedure is being initiated following

restoration of data link service. LOGGING ON TO (facility designation)

To advise ATC that a delayed CPDLC uplink

has been received and to request clarification

of the intent of the CPDLC message. DELAYED CPDLC MESSA GE RECEIVED

(requests)

E-1

10/3/17 AC 90 -117

Appendix E

Table E -2. Voice Phraseology R elated to CPDLC From the ATSU

Condition Voice Phraseology

To advise all stations or a specific flight of a

complete ground system failure and provide

further instructions. (ICAO Doc 4444) (ALL STATIONS) CPDLC FAILURE

(instructions).

Example:

ALL STATIONS CPDLC FAILURE. DISCONNECT CPDLC. CONTINUE ON

VOICE

To instruct the pilot of a single CPDLC

message failure. ( ICAO Doc 4444 ) CPDLC MESSAGE FAILURE (appropriate

clearance, instruction, informatio n or request)

To instruct the pilot of a correction to a

CPDLC clearances, instructions, information

or requests. (ICAO Doc 4444) DISREGARD CPDLC (message type)

MESSAGE, BREAK (correct clearance,

instruction, information or request)

To instruct all stati ons or a specific flight to

avoid sending CPDLC requests for a limited

period of time. (ICAO Doc 4444) (ALL STATIONS) STOP SENDING CPDLC

REQUESTS (UNTIL ADVISED) ((reason))

To instruct the pilot to manually initiate a

logon/notification to the subsequent ATSU. DISCONNECT CPDLC THEN LOGON TO

(facility designation)

Note 1: The (facility designation) is the four character ICAO code.

Note 2: Use this voice phraseology when the CPDLC transfer to an adjacent ATSU has

failed.

To advise the pilot prior to the com mencement

of a CPDLC shutdown and instruct them to

continue on voice. CPDLC WILL BE SHUT DOWN.

DISCONNECT CPDLC. CONTINUE ON

VOICE

To advise all stations or a specific flight to

resume normal CPDLC operations and provide

the logon /notification address. (ALL STATIONS) RESUME NORMAL

CPDLC OPERATIONS. LOGON TO (facility

designation)

E-2

10/3/17 AC 90 -117

Appendix F

APPENDIX F. CONTRO LLER -PILOT DATA LINK COMMUNICATION ( CPDLC )

UPLINK AND DOWNLINK TABLES

Table F -1. Color Key

Blue Uplink Tables

Green Downlink Tables

Table F -2. Response A ttribute of CPDLC Message E lement for Uplink Messages

Response

Attribute Description

W/U Response required. Yes

Valid responses. WILCO, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY,

NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if

required), ERROR

Note: WILCO, UNABLE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT

DATA AUTHORITY and ERROR will close the uplink message.

FANS 1/A: WILCO, UNABLE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

A/N Response required. Yes

Valid responses. AFFIRM, NEGATIVE, STANDBY, NOT CURRENT DATA AUTHORITY,

NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if

required), ERROR

Note: AFFIRM, NEGATIVE, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT

DATA AUTHORITY and ERROR will close the upl ink message.

FANS 1/A: AFFIRM, NEGATIVE, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY.

R Response required. Yes

Valid responses. ROGER, UNABLE, STANDBY, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA AUTHORITY, LOGICAL ACKNOWLEDGEMENT (only if

require d), ERROR

Note: ROGER, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT DATA

AUTHORITY and ERROR will close the uplink message.

FANS 1/A: ROGER, STANDBY, ERROR, NOT CURRENT DATA AUTHORITY. FANS 1/A

aircraft do not have the capability to send UNABLE in respo nse to an uplink message containing

message elements with an “R” response attribute. For these aircraft, the pilot may use alternative

means to UNABLE the message. These alternative means will need to be taken into consideration to

ensure proper technical and operational closure of the communication transaction.

F-1

10/3/17 AC 90 -117

Appendix F

Response

Attribute Description

Y Response required. Yes

Valid responses: Any CPDLC downlink message, L OGICAL ACKNOWLEDGEMENT

(only if required)

N Response required. No, unless logical acknowledgement required.

Valid Responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL

ACKNOWLEDGEMENT, NOT CURRENT DATA AUTHORITY, NOT AUTHORIZED NEXT

DATA AUTHORITY, ERROR

FANS 1/A: Defined “Response not required,” but not used. Under some circumstances, an ERROR

message will also clos e an uplink message.

NE [Not defined in International Civil Aviation Organization (ICAO) Doc 4444]

FANS 1/A: The WILCO, UNABLE, AFFIRM, NEGATIVE, ROGER, and STANDBY responses are

not enabled (NE) for pilot selection. An uplink message with a response attribute NE is considered to

be closed even though a response may be required operationally. Under some circumst ances,

a downlink error message may be linked to an uplink message with a NE attribute.

Table F -3. Response Attribute of CPDLC Message Element for Downlink Messages

Response

Attribute Description

Y Response required. Yes

Valid responses: Any CPDLC uplink message, LOGICAL ACKNOWLEDGEMENT

(only if required).

N Response required. No, unless logical acknowledgement required.

Valid responses (only if LOGICAL ACKNOWLEDGEMENT is required). LOGICAL ACKNOWLEDGEMENT, MESSAGE NOT SUPPORTED BY THIS ATC UNIT , ERROR

FANS 1/A: Aircraft do not have the capability to receive technical responses to downlink message

elements with an “N” response attribute (other than LACK or ERROR for ATN B1 aircraft).

In some cases, the response attribute is different between FANS 1/A aircraft and ICAO Doc 4444.

As an example, most emergency messages have an “N” response attribute for FANS 1/A whereas

ICAO Doc 4444 defines a “Y” response attribute for them. As a consequence, for FANS 1/A aircraft,

the ATC will need to use alternative means to acknowledge to the pilot that an emergency message

has been received.

F-2

10/3/17 AC 90 -117

Appendix F

Table F -4. Route Uplink Message Elements (RTEU)

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RTEU -1 Instruction to proceed via the

specified departure clearance. (departure clearance) W/U UM169 (free text)

Note: UM169 may be

combined with UM158

ATIS (ATIS code)

and/or UM123

SQUAWK (beacon)

code) and/or UM19

MAINTAIN (altitude) . N/A

RTEU -2 Instruction to proceed directly

to the specified position. PROCEED DIRECT TO (

position) W/U UM

74 PROCEED

DIRECT TO (position) UM74 PROCEED DIRECT TO

(position)

RTEU -2 Instruction to proceed directly

to the specified position. PROCEED DIRECT TO (

position) W/U UM

75 WHEN ABLE

PROCEED DIRECT

TO (position)

Note: This message element is equivalent to SUPU -5 plus

RTEU -2 in

ICAO Doc 4444. N/A

RTEU -3 Instruction to proceed, at the

specified time, directly to the

specified position. AT TIME (time) PROCEED

DIRECT TO (position) W/U UM76 AT (time)

PROCEED DIRECT TO (position) N/A

RTEU -4 Instruction to proceed, at the

specified position, directly to

the next specified position. AT (position) PROCEED

DIRECT TO (position) W/U UM77 AT (position)

PROCEED DIRECT TO (position) N/A

RTEU -5 Instruction to proceed upon

reaching the specified level,

directly to the specified

position. AT (level single) PROCEED

DIRECT TO (position) W/U UM78 AT (altitude)

PROCEED DIRECT

TO (position) N/A

F-3

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CP DLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RTEU -6 Instruction to proceed to the

specified position via the specified route. CLEARED TO (position) VIA

(departure data[O]) (en- route

data) W/U UM79 CLEARED TO (position) VIA

(route clearance) UM79 CLEARED TO (position) VIA (route

clearance)

RTEU -7 Instruction to proceed via the specified route. CLEARED (departure

data[O]) (en- route data)

(arrival approach data) W/U UM80 CLEARED (route clearance) UM80 CLEARED (route clearance)

RTEU -8 Instruction to proceed in accordance with the specified procedure.

CLEARED (procedure name) W

/U UM81 CLEARED (procedure name) N/A

RTEU -9 Instruction to proceed from the specified position via the specified route. AT (position) CLEARED

(en-route data) (arrival

approach data) W/U UM83 AT (position)

CLEARED (route clearance) N/A

RTEU -10 Instruction to proceed from the specified position via the specified procedure. AT (position) CLEARED

(procedure name) W/U UM84 AT (position)

CLEARED (procedure

name) N/A

RTEU -11 Instruction to enter a holding pattern at the specified position in accordance with the specified instructions.

Note: RTEU -13 EXPECT

FURTHER CLEARANCE AT TIME (time) is appended to

this message when an extended

hold is anticipated. AT (position) HOLD

INBOUND TRACK

(degrees)(direction) TURNS

(leg type) LEGS W/U UM91 HOLD AT (position) MAINTAIN

(altitude) INBOUND

TRACK (degrees)

(direction) TURN

LEG TIME (leg type) N/A

F-4

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RTEU -12 Instruction to enter a holding

pattern at the specified position

in accordance with the published holding instructions.

Note: RTEU -13 EXPECT

FURTHER CLEARANCE AT

TIME (time) is appended to this

message when an extended hold

is anticipated. AT (position) HOLD AS

PUBLISHED W/U UM9 2 HOLD

AT (position)

AS PUBLISHED

MAINTAIN (altitude) UM92 HOLD AT

(position) AS

PUBLISHED MAINTAIN (level)

RTEU -13 Notification that an onwards

clearance may be issued at the specified time. EXPECT FURTHER

CLEARANCE AT TIME (time) R UM93 EXPECT

FURTHER CLEARANCE AT

(time) N/A

RTEU -14 Notification that a clearance

may be issued for the aircraft to fly the specified procedure or clearance name. EXPECT (named instruction) R UM99 EXPECT

(procedure name)

Note: Used when a

published procedure is

designated.

UM169 ‘EXPECT

(clearance name) ’

Note: Used when an

unpublished clearance/procedure

name is designated. N/A

RTEU -15 Request to confirm the assigned

route. CONFIRM ASSIGNED

ROUTE Y UM137 CONFIRM

ASSIGNED ROUTE

Note: NE response

attribute. N/A

F-5

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RTEU -16 Request to make a position

report. REQUEST POSITION

REPORT Y UM147 REQUEST

POSITION REPORT N/A

RTEU -17 Request to provide the

estimated time of arrival at the

specified position. ADVISE ETA (position) Y UM169 ‘ADVISE

ETA (position) ’ N/A

F-6

10/3/17 AC 90 -117

Appendix F

Table F -5. Route Downlink Message Elements (RTED)

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RTED -1 Request for a direct clearance to

the specified position. REQUEST DIRECT TO

(position) Y DM22 REQUEST

DIRECT TO (position) DM22 REQUEST

DIRECT TO

(position)

RTED -2 Request for the specified

procedure or clearance name. REQUEST (named instruction) Y DM23 REQUEST

(procedure name) N/A

RTED -3 Request for the specified route. REQUEST CL EARANCE

(depart ure data[O])

(en-route data)

(arrival approach data[O]) Y DM24 REQUEST

(route clearance) N/A

RTED -4 Request for the specified

clearance. REQUEST (clearance type)

CLEARANCE Y DM25 REQUEST

CLEARANCE N/A

RTED -5 Position report. POSITION REPORT

(position report) N DM48 POSITION

REPORT ( position

report) N/A

RTED -6 Request for the specified

heading. REQUEST HEADING

(degrees) Y DM70 REQUEST

HEADING (degrees) N/A

RTED -7 Request for the specified ground

track. REQUEST GROUND TRACK

(degrees) Y DM71 REQUEST

GROUND TRACK

(degrees) N/A

RTED -8 Request for the time or position

that can be expected to rejoin the

cleared route. WHEN CAN WE EXPECT

BACK ON ROUTE Y DM51 WHEN CAN

WE EXPECT BACK

ON ROUTE N/A

RTED -9 Confirmation that the assigned

route is the specified route. ASSIGNED ROUTE

(departure data[O])

(en-route data)

(arrival approach data[O]) N DM40 ASSIGNED

ROUTE

(route clearance) N/A

RTED -10 Notification of estimated time of

arrival at the specified position. ETA (position) TIME (time) N DM67 ‘ETA (position)

TIME (time) ’ N/A

F-7

10/3/17 AC 90 -117

Appendix F

Table F-6. Lateral Uplink Message Elements (LATU)

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LATU -1 Instruction to fly a parallel track

to the cleared route at a

displacement of the specified

distance in the specified

direction. OFFSET (specified distance)

(direction) OF ROUTE W/U UM64 OFFSET

(distance offset)

(direction)

OF ROUTE UM64 OFFSET

(specified distance) (direction)

OF ROUTE

LATU -2 Instruction to fly a parallel track

to the cleared route at a

displacement of the specified distance in the specified

direction and commencing at the

specified position. AT (position) OFFSET

(specified distance)

(direction) OF ROUTE W/U UM65 AT (position)

OFFSET (distance offset)

(direction)

OF ROUTE N/A

LATU -3 Instruction to fly a parallel track

to the cleared route at a

displacement of the specified

distance in the specified

direction and commencing at the

specified time. AT TIME (time) OFFSET

(specified distance) (direction) OF ROUTE W/U UM66 AT (time)

OFFSET (distance offset)

(direction) OF

ROUTE N/A

LATU -4 Instruction to rejoin the cleared

route. REJOIN ROUTE W/U UM67 PROCEED

BACK ON ROUTE N/A

LATU -5 Instruction to rejoin the cleared

route before passing the

specified position. REJOIN ROUTE BEFORE

PASSING (position) W/U UM68 REJOIN

ROUTE BY (position) N/A

LATU -6 Instruction to rejoin the cleared

route before the specified time. REJOIN ROUTE BEFORE

TIME (time) W/U UM69 REJOIN

ROUTE BY (time) N/A

LATU -7 Notification that a clearance

may be issued to enable the aircraft to rejoin the cleared

route before passing the

specified position. EXPE CT BACK ON ROUTE

BEFORE PASSING (position) R UM70 EXPECT

BACK ON ROUTE

BY (position) N/A

F-8

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LATU -8 Notification a clearance may be

issued to enable the aircraft to

rejoin the cleared route before

the specified time. EXPECT BACK ON ROUTE

BEFORE TIME (time) R UM71 EXPECT

BACK ON ROUTE BY (time) N/A

LATU -9 Instruction to resume own

navigation following a period of

tracking or heading clearances.

May be used in conjunction with

an instruction on how or where

to rejoin the cleared route. RESUME OWN

NAVIGATION W/U UM72 RESUME

OWN NAVIGATION UM72 RESUME

OWN NAVIGATION

LATU -10 Instruction allowing deviation

up to the specified distance(s)

from the cleared route in the

specified direction(s). CLEARED TO DEVIATE

UP TO (lateral deviation)

OF ROUTE W/U UM82 CLEARED TO

DEVIATE UP TO

(distance offset)

(direction)

OF ROUTE UM82 CLEARED TO

DEVIATE UP TO

(specified distance)

(direction)

OF ROUTE

LATU -11 Instruction to turn left or right as

specified on to the specified

heading. TURN (direction) HEADING

(degrees) W/U UM94 TURN

(direction) HEADING

(degrees) UM94 TURN

(direction) HEADING

(degrees)

LATU -11 Instruction to turn left or right as

specified on to the specified heading. TURN (direction) HEADING

(degrees) W/U UM98

IMMEDIATELY TURN (direction)

HEADING (degrees)

Note: This message

element is equivalent

to EMGU -2 plus

LATU -11 in

ICAO Doc 4444. N/A

LATU -12 Instruction to turn left or right as

specified on to the specified

track. TURN (direction) GROUND

TRACK (degrees) W/U UM95 TURN

(direction)

GROUND TRACK

(degrees) N/A

F-9

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LATU -13 Instruction to turn the specified

number of degrees left or right. TURN (direction) (number of

degrees) DEGREES W/U N/A UM215 TURN

(direction) (degrees)

LATU -14 Instruction to continue to fly the

present heading. CONTINUE PRESENT

HEADING W/U UM96 FLY PRESENT

HEADING UM96 CONTINUE

PRESENT HEADING

LATU -15 Instruction to fly the specified

heading upon reaching the

specified position. AT (position) FLY HEADING

(degrees) W/U UM97 AT (position)

FLY HEADING

(degrees) N/A

LATU -16 Instruction to fly the specified

heading. FLY HEADING (degrees) W/U N/A UM190 FLY

HEADING (degrees)

LATU -17 Instruction to report when clear

of weather. REPORT CLEAR OF

WEATHER W/U UM169 ‘REPORT

CLEAR OF

WEATHER’

Note: R response

attribute. N/A

LATU -18 Instruction to report when the

aircraft is back on the cleared

route. REPORT BACK ON ROUTE W/U UM127 REPORT

BACK ON ROUTE

Note: R response

attribute. N/A

LATU -19 Instruction to report upon

passing the specified position. REPORT PASSING (position) W/U UM130 REPORT

PASSING (position)

Note: R response

attribute. N/A

F-10

10/3/17 AC 90 -117

Appendix F

Table F -7. Lateral Downlink Message Elements (LATD)

Operational Definition in PANS- ATM (Doc 4444) C PDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LATD -1 Request for a parallel track from

the cleared route at a displacement of the specified distance in the specified direction. REQUEST OFFSET (specified distance) (direction)

OF ROUTE Y DM15 REQUEST OFFSET (specified

distance) (direction)

OF ROUTE N/A

LATD -2 Request for a weather deviation up to the specified distance(s) off track in the specified direction(s). REQUEST WEATHER DEVIATION UP TO (lateral deviation) OF ROUTE Y DM27 REQUEST WEATHER DEVIATION UP TO (specified distance)

(direction)

OF ROUTE DM27 REQUEST

WEATHER DEVIATION UP TO (specified distance)

(direction)

OF ROUTE

LATD -3 Report indicating that the aircraft is clear of weather. CLEAR OF WEATHER N DM69 ‘CLEAR OF WEATHER’ N/A

LATD -4 Report indicating that the cleared

route has been rejoined. BACK ON ROUTE N DM41 BACK ON ROUTE N/A

LATD -5 Report indicating diverting to the specified position via the

specified route, which may be

sent without any previous

coordination done with ATC. DIVERTING TO (position)

VIA (en-route data) (arrival

approach data[O]) Y DM59 DIVERTING TO (position) VIA

(route clearance)

Note 1: H alert

attribute.

Note 2: N response

attribute. N/A

LATD -6 Report indicating that the aircraft

is offsetting to a parallel track at the specified distance in the specified direction off from the

cleared route. OFFSETTING (specified

distance) (direction) OF

ROUTE Y DM60 OFFSETTING

(distance offset) (direction)

OF ROUTE

Note 1: H alert

attribute.

Note 2: N response

attribute. N/A

F-11

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) C PDLC Message Sets

Message Element

Identifier M

essage Element Intended Use Format for Message Element

Display R

esp. FANS 1/A ATN B1

LATD -7 Report indicating deviating

specified distance or degrees in the specified direction from the cleared route. DEVIATING (Specified Deviation)

(direction) OF ROUTE

Y

DM80 DEVIATING (Deviation Offset)

(direction) OF

ROUTE

Note 1: H alert

attribute.

Note 2: N response

attribute . N/

A

LATD -8 Report indicating passing the

specified position. PASSING (position) N DM31 PASSING (position) N/ A

F-12

10/3/17 AC 90 -117

Appendix F

Table F -8. Level Uplink Message Elements (LVLU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -1 Notification that an instruction

may be expected for the aircraft

to commence climb at the

specified time. EXPECT HIGHER AT TIME

(time) R UM7 EXPECT

CLIMB AT (time) N/A

LVLU -2 Notification that an instruction

may be expected for the aircraft

to commence climb at the

specified position. EXPECT HIGHER AT

(position) R UM8 EXPECT

CLIMB AT (position) N/A

LVLU -3 Notification that an instruction

may be expected for the aircraft

to commence descent at the

specified time. EXPECT LOWER AT TIME

(time) R UM9 EXPECT

DESCENT AT (time) N/A

LVLU -4 Notification that an instruction

may be expected for the aircraft

to commence descent at the

specified position. EXPECT LOWER AT

(position) R UM10 EXPECT

DESCENT AT (position) N/A

LVLU -5 Instruction to maintain the

specified level or vertical range. MAINTAIN (level) W/U UM19 MAINTAIN

(altitude)

Note: Used for a single

level.

UM30 MAINTAIN

BLOCK (altitude) TO

(altitude)

Note: Used for a

vertical range. UM19 MAINTAIN

(level)

F-13

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -6 Instruction that a climb to the

specified level or vertical range

is to commence and once reached is to be maintained. CLIMB TO (level) W/U UM20 CLIMB TO

AND MAINTAIN (altitude)

Note:

Used for a single

level.

UM31 CLIMB TO AND MAINTAIN BLOCK (altitude) TO

(altitude)

Note: Used for a

vertical range. UM20 CLIMB TO

(level)

LVLU -6 Instruction that a climb to the

specified level or vertical range is to commence and once reached is to be maintained. CLIMB TO (level) W/U UM36 EXPEDITE

CLIMB TO (altitude)

Note: This message

element is equivalen t

to SUPU -3 plus

LVLU -6 in

ICAO Doc 4444.

UM38 IMMEDIATELY CLIMB TO (altitude)

Note: This message

element is equivalen t

to EMGU -2 plus

LVLU -6 in

ICAO Doc 4444. N/A

F-14

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -7 Instruction that at the specified

time a climb to the specified

level or vertical range is to commence and once reached is to be maintained.

Note: This message element

would be preceded with LVLU -5

MAINTAIN (level), to prevent

the premature execution of the

instruction. AT TIME (time) CLIMB TO

(level) W/U UM21 AT (time)

CLIMB TO AND

MAINTAIN (altitude)

Note: A vertical range

cannot be provided. N/A

LVLU -8 Instruction that at the specified

position a climb to the specified level or vertical range is to commence and once reached is to be maintained.

Note: This message element

would be preceded with LVLU -5

MAINTAIN (level), to prevent

the premature execution of the

instruction. AT (position) CLIMB TO

(level) W/U UM22 AT (position)

CLIMB TO AND MAINTAIN (altitude)

Note: A vertical range

cannot be provided. N/A

LVLU -9 Instruction that a descent to the

specified level or vertical range is to commence and once

reached is to be maintained. DESCEND TO (level) W/U UM23 DESCEND TO

AND MAINTAIN

(altitude)

Note: Used for a single

level. UM23 DESCEND TO

(level)

F-15

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -9 Instruction that a descent to the

specified level or vertical range

is to commence and once reached is to be maintained. DESCEND TO (level) W/U UM32 DESCEND TO

AND MAINTAIN

BLOCK (altitude) TO

(altitude)

Note : Used for a

vertical range.

UM39

IMMEDIATELY

DESCEND TO

(altitude)

Note: This message

element is equivalent

to EMGU -2 plus . N/A

LVLU -10 Instruction that at the specified

time a descent to the specified

level or vertical range is to commence and once reached is

to be maintained. AT TIME (time) DESCEND

TO (level) W/U UM24 AT (time)

DESCEND TO AND MAINTAIN (altitude)

Note: A vertical range

cannot be provided. N/A

LVLU -11 Instruction that at the specified

position a descent to the specified level or vertical range is to commence and once

reached is to be maintained. AT (position) DESCEND TO

(level) W/U UM25 AT (position)

DESCEND TO AND MAINTAIN (altitude)

Note: A vertical range

cannot be provided. N/A

LVLU -12 Instruction that a climb is to be

completed such that the specified level is reached before

the specified time. CLIMB TO REACH (level

single) BEFORE TIME (time) W/U UM26 CLIMB TO

REACH (altitude) BY

(time) UM26 CLIMB TO

REACH (level) BY

(time)

LVLU -13 Instruction that a climb is to be

completed such that the specified level is reached before

passing the specified position. CLIMB TO REACH (level

single) BEFORE PASSING

(position) W/U UM27 CLIMB TO

REACH (altitude) BY

(position) UM27 CLIMB TO

REACH (level) BY

(position)

F-16

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -14 Instruction that a descent is to be

completed such that the

specified level is reached before

the specified time. DESCEND TO REACH

(level single) BEFORE TIME

(time) W/U UM28 DESCEND TO

REACH (altitude)

BY (time) UM28 DESCEND TO

REACH (level)

BY (time)

LVLU -15 Instruction that a descent is to be

completed such that the specified level is reached before

passing the specified position. DESCEND TO REACH

(level single) BEFORE

PASSING (position) W/U UM29 DESCEND TO

REACH (altitude)

BY (position) UM29 DESCEND TO

REACH (level)

BY (position)

LVLU -16 Instruction to stop the climb at

the specified level and, once reached, this level is to be maintained. The specified level

will be below the previously

assigned level. This instruction should only be issued when the controller can confirm that the previously assigned level has

not yet been reached. STOP CLIMB AT (level

single) W/U UM169 ‘STOP

CLIMB AT (altitude) ’

Note: R response

attribute. N/A

LVLU -17 Instruction to stop the descent at

the specified level and, once

reached, this level is to be

maintained. The specified level will be above the previously assigned level. This instruction should only be issued when the controller can confirm that the

previously assigned level has

not yet been reached. STOP DESCENT AT (level

single) W/U UM169 ‘STOP

DESCENT AT

(altitude) ’

Note: R response

attribute. N/A

LVLU -18 Instruction to climb at the

specified rate or greater. CLIMB AT (vertical rate) OR

GREATER W/U UM171 CLIMB AT

(vertical rate)

MINIMUM UM171 CLIMB AT

(vertical rate)

MINIMUM

F-17

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -19 Instruction to climb at the

specified rate or less. CLIMB AT (vertical rate) OR

LESS W/U UM172 CLIMB AT

(vertical rate)

MAXIMUM UM172 CLIMB AT

(vertical rate)

MAXIMUM

LVLU -20 Instruction to descend at the

specified rate or greater. DESCEND AT (vertical rate)

OR GREATER W/U UM173 DESCEND

AT (vertical rate)

MINIMUM UM173 DESCEND

AT (vertical rate)

MINIMUM

LVLU -21 Instruction to descend at the

specified rate or less. DESCEND AT (vertical rate)

OR LESS W/U UM174 DESCEND

AT (vertical rate)

MAXIMUM UM174 DESCEND

AT (vertical rate)

MAXIMUM

LVLU -22 Notification that a clearance

may be issued for the aircraft to

commence a climb to the specified level at the specified number of minutes after

departure. EXPECT (level single)

(number of minutes) AFTER

DEPARTURE R UM169 ‘EXPECT

(level single) (number of minutes) AFTER

DEPARTURE’ N/A

LVLU -23 Instruction to report upon

leaving the specified level. REPORT LEAVING (level

single) W/U UM128 REPORT

LEAVING (altitude)

Note: R response

attribute. N/A

LVLU -24 Instruction to report upon

maintaining the specified level. REPORT MAINTAINING

(level single) W/U UM129 REPORT

LEVEL (altitude)

Note: R response

attribute. N/A

LVLU -25 Instruction to report the present

level. REPORT PRESENT LEVEL Y N/A

Note: Refer to A.6 . UM133 REPORT

PRESENT LEVEL

LVLU -26 Instruction to report upon

reaching the specified vertical range. REPORT REACHING

BLOCK (level single) TO

(level single) W/U UM180 REACHING

BLOCK (altitude) TO

(altitude)

Note: R response

attribute. N/A

F-18

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLU -27 Request to confirm the assigned

level. CONFIRM ASSIGNED

LEVEL Y UM135 CONFIRM

ASSIGNED

ALTITUDE

Note: NE response

attribute. N/A

LVLU -28 Request to provide the preferred

level. ADVISE PREFERRED

LEVEL Y UM169 ‘ADVISE

PREFERRED LEVEL’

Note: R response

attribute. UM231 STATE

PREFERRED LEVEL

LVLU -29 Request to provide the preferred

time and/or position to

commence descent to the

aerodrome of intended arrival. ADVISE TOP OF DESCENT Y UM169 ‘ADVISE

TOP OF DESCENT’

Note: R response

attribute. UM232 STATE TOP

OF DESCENT

LVLU -30 Request for the earliest time or

position when the specified level

can be accepted. WHEN CAN YOU ACCEPT

(level single) Y UM148 WHEN CAN

YOU ACCEPT (altitude)

Note: NE response

attribute. UM148 WHEN CAN

YOU ACCEPT (level)

LVLU -31 Request to indicate whether or

not the specified level can be accepted at the specified

position. CAN YOU ACCEPT (level

single) AT (position) A/N UM149 CAN YOU

ACCEPT (altitude)

AT (position) N/A

LVLU -32 Request to indicate whether or

not the specified level can be

accepted at the specified time. CAN YOU ACCEPT (level

single) AT TIME (time) A/N UM150 CAN YOU

ACCEPT (altitude)

AT (time) N/A

LVLU -33 Instruction to expedite a descent

to the specified level is to commence and once reached the

specified level is to be

maintained. EXPEDITE DESCENT TO

(level single) W/U UM37 EXPEDITE

DESCENT TO

(altitude) N/A

F-19

10/3/17 AC 90 -117

Appendix F

Table F -9. Level Downlink Message Elements (LVLD )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLD -1 Request to fly at the specified

level or vertical range. REQUEST (level) Y DM6 REQUEST

(altitude)

Note: Used for a single

level.

DM7 REQUEST

BLOCK (altitude) TO

(altitude)

Note: Used for a vertical

range. DM6 REQUEST

(level)

LVLD -2 Request for a climb to the

specified level or vertical range. REQUEST CLIMB TO (level) Y DM9 REQUEST CLIMB

TO (altitude)

Note: Use of DM7

REQUEST BLOCK (altitude) TO (altitude) to request to climb at a

vertical range. DM9 REQUEST

CLIMB TO (level)

LVLD -3 Request for a descent to the

specified level or vertical range. REQUEST DESCENT TO

(level) Y DM10 REQUEST

DESCENT TO (altitude)

Note: Use of DM7 REQUEST BLOCK

(altitude) TO (altitude) to request to descend at a

vertical range. DM10 REQUEST

DESCENT TO (level)

F-20

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLD -4 Request for a climb/descent to

the specified level or vertical

range to commence at the

specified position. AT (position) REQUEST

(level) Y DM11 AT (position)

REQUEST CLIMB TO

(altitude)

Note: A vertical range

cannot be requested.

DM12 AT (position)

REQUEST DESCENT

TO (altitude)

Note: A vertical range

cannot be requested. N/A

LVLD -5 Request for a climb/descent to

the specified level or vertical

range to commence at the specified time. AT TIME (time) REQUEST

(level) Y DM13 AT TIME (time)

REQUEST CLIMB TO

(altitude)

Note: A vertical range

cannot be requested.

DM14 AT TIME (time)

REQUEST DESCENT

TO (altitude)

Note: A vertical range

cannot be requested. N/A

LVLD -6 Request for the earliest time or

position that a descent can be

expected. WHEN CAN WE EXPECT

LOWER LEVEL Y DM52 WHEN CAN WE

EXPECT LOWER

ALTITUDE N/A

LVLD -7 Request for the earliest time or

position that a climb can be

expected. WHEN CAN WE EXPECT

HIGHER LEVEL Y DM53 WHEN CAN WE

EXPECT HIGHER

ALTITUDE N/A

LVLD -8 Report indicating leaving the

specified level. LEAVING (level single) N DM28 LEAVING

(altitude) N/A

LVLD -9 Report indicating that the

specified level is being

maintained. MAINTAINING (level single) N DM37 LEVEL (altitude) N/A

F-21

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLD -10 Report indicating reaching the

specified vertical range. REACHING BLOCK (level

single) TO (level single) N DM76 REACHING

BLOCK (altitude) TO

(altitude) N/A

LVLD -11 Confirmation that the assigned

level or vertical range is the

specified level or vertical range. ASSIGNED LEVEL (level) N DM38 ASSIGNED ALTITUDE (altitude)

Note: Used for a single

level .

DM77 ASSIGNED

BLOCK (altitude) TO

(altitude)

Note: Used for a vertical

range . DM38 ASSIGNED

LEVEL (level)

LVLD -12 Report indicating that the

aircraft’s preferred level is the

specified level. PREFERRED LEVEL (level single) N DM67‘PREFERRED

LEVEL (altitude) ’

Note 1: Response to free text UM169 ‘ADVISE PREFERRED LEVEL’

Note 2: When

pre-formatting of the

downlink message is not

available, the pilot can

shorten to: FL (altitude). DM106 PREFERRED

LEVEL (level)

Note A vertical range

may be provided.

LVLD -13 Report indicating climbing to the specified level. CLIMBING TO (level single) N DM29 CLIMBING TO

(altitude) N/A

F-22

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

LVLD -14 Report indicating descending to

the specified level. DESCENDING TO (level

single) N DM30 DESCENDING

TO (altitude)

Note: N alert attribute.

DM61 DESCENDING TO (altitude)

Note: Urgent alert

attribute. N/A

LVLD -15 Indication that the specified level

can be accepted at the specified time. WE CAN ACCEPT (level

single) AT TIME (time) N DM67 ‘WE CAN ACCEPT (altitude) AT

TIME (time) ’ DM81 WE CAN

ACCEPT (level) AT

(time)

Note: A vertical range

may be provided.

LVLD -16 Indication that the specified level

can be accepted at the specified

position. WE CAN ACCEPT (level

single) AT (position) N DM67 ‘WE CAN ACCEPT (altitude) AT

(position) ’ N/A

LVLD -17 Indication that the specified level

cannot be accepted. WE CANNOT ACCEPT (level single) N DM67. ‘WE CANNOT

ACCEPT (altitude) ’ DM82 WE CANNOT

ACCEPT (level)

Note: A vertical range

may be provided.

LVLD -18 Notification of the preferred time

and position to commence

descent for approach. TOP OF DESCENT (position)

TIME (time) N DM67 ‘TOP OF

DESCENT (time) ’

Note: When

pre-formatting of the

downlink message is not

available, the pilot can

shorten to:

TOD (time). DM109 TOP OF

DESCENT (time)

LVLD -19 Notification of the present level. Present level (single level) N N/A

Note: Refer to A.6 . DM32 PRESENT

LEVEL (altitude)

F-23

10/3/17 AC 90 -117

Appendix F

Table F -10. Crossing Constraint Uplink Messages (CSTU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

CSTU -1 Instruction that the specified

position is to be crossed at the

specified level or within the specified vertical range. CROSS (position) AT (level) W/U UM46 CROSS

(position) AT

(altitude)

Note: Used for a single

level. UM46 CROSS

(position) AT (level)

CSTU -1 Instruction that the specified

position is to be crossed at the specified level or within the specified vertical range. CROSS (position) AT (level) UM50 CROSS

(position) BETWEEN

(altitude) AND

(altitude)

Note: Used for a

vertical range. UM46 CROSS

(position) AT (level)

CSTU -1 Instruction that the specified

position is to be crossed at the specified level or within the specified vertical range. CROSS (position) AT (level) W/U UM49 CROSS

(position) AT

AND MAINTAIN

(altitude)

Note 1: A vertical

range cannot be

provided.

Note 2: This message

element is equivalent

to CSTU -1 plus

LVLU -5 in

ICAO Doc 4444. N/A

CSTU -2 Instruction that the specified

position is to be crossed at or

above the specified level. CROSS (position) AT OR

ABOVE (level single) W/U UM47 CROSS

(position) AT OR

ABOVE (altitude) UM47 CROSS

(position) AT OR

ABOVE (level)

CSTU -3 Instruction that the specified

position is to be crossed at or

below the specified level. CROSS (position) AT OR

BELOW (level single) W/U UM48 CROSS

(position) AT OR

BELOW (altitude) UM48 CROSS

(position) AT OR

BELOW (level)

F-24

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

CSTU -4 Instruction that the specified

position is to be crossed at the

specified time. CROSS (position) AT TIME

(time) W/U UM51 CROSS

(position) AT (time) UM51 CROSS

(position) AT (time)

CSTU -5 Instruction that the specified

position is to be crossed before

the specified time. CROSS (position) BEFORE

TIME (time) W/U UM52 CROSS

(position) AT OR

BEFORE (time) UM52 CROSS

(position) AT OR

BEFORE (time)

CSTU -6 Instruction that the specified

position is to be crossed after the

specified time. CROSS (position) AFTER

TIME (time) W/U UM53 CROSS

(position) AT OR

AFTER (time) UM53 CROSS

(position) AT OR

AFTER (time)

CSTU -7 Instruction that the specified

position is to be crossed between

the specified times. CROSS (position)

BETWEEN TIME (time)

AND TIME (time) W/U UM54 CROSS

(position) BETWEEN

(time) AND (time) UM54 CROSS

(position) BETWEEN

(time) AND (time)

CSTU -8 Instruction that the specified

position is to be crossed at the

specified speed. CROSS (position) AT (speed) W/U UM55 CROSS

(position) AT (speed) UM55 CROSS

(position) AT (speed)

CSTU -9 Instruction that the specified

position is to be crossed at or

less than the specified speed. CROSS (position) AT

(speed) OR LESS W/U UM56 CROSS

(position) AT OR

LESS THAN (speed) N/A

CSTU -10 Instruction that the specified

position is to be crossed at or

greater than the specified speed. CROSS (position) AT

(speed) OR GREATER W/U UM57 CROSS

(position) AT OR

GREATER THAN

(speed) N/A

F-25

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

CSTU -11 Instruction that the specified

position is to be crossed at the specified time and at the level or within the vertical range as specified. CROSS (position) AT TIME

(time) AT (level) W/U UM58 CROSS

(position) AT (time)

AT (altitude)

Note: A vertical range

cannot be provided.

UM62 AT (time)

CROSS (position) AT

AND MAINTAIN

(altitude)

Note 1: A vertical

range cannot be

provided.

Note 2: This message

element is equivalent

to CSTU -11 plus

LVLU -5 in

ICAO Doc 4444. N/A

CSTU -12 Instruction that the specified

position is to be crossed before the specified time and at the level or within the vertical range as specified. CROSS (position) BEFO RE

TIME (time) AT (level) W/U UM59 CROSS

(position) AT OR

BEFORE (time) AT (altitude)

Note: A vertical range

cannot be provided. N/A

CSTU -13 Instruction that the specified

position is to be crossed after the

specified time and at the level or

within the vertical range as specified. CROSS (position) AFTER

TIME (time) AT (level) W/U UM60 CROSS

(position) AT OR

AFTER (time) AT (altitude)

Note: A vertical range

cannot be provided. N/A

F-26

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

CSTU -14 Instruction that the specified

position is to be crossed at the

level or within the vertical range, as specified, and at the specified speed. CROSS (position) AT (level)

AT (speed) W/U UM61 CROSS

(position) AT AND

MAINTAIN (altitude)

AT (speed)

Note 1: A vertical

range cannot be

provided.

Note 2: This message

element is equivalent

to CSTU -14 plus

LVLU -5 in

ICAO Doc 4444. UM61 CROSS

(position) AT AND

MAINTAIN (level)

AT (speed)

CSTU -15 Instruction that the specified

position is to be crossed at the specified time at the level or

within the vertical range, as

specified, and at the specified speed. CROSS (position) AT TIME

(time) AT (level) AT (speed) W/U UM63 AT (time)

CROSS (position) AT

AND MAINTAIN

(altitude) AT (speed)

Note 1: A vertical

range cannot be

provided.

Note 2: This message

element is equivalent

to CSTU -15 plus

LVLU -5 in

ICAO Doc 4444. N/A

F-27

10/3/17 AC 90 -117

Appendix F

Table F-11. Speed Uplink Messages (SPDU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPDU -1 Notification that a speed

instruction may be issued to take

effect at the specified time. EXPECT SPEED CHANGE

AT TIME (time) R UM100 AT (time)

EXPECT (speed) N/A

SPDU -2 Notification that a speed

instruction may be issued to take

effect at the specified position. EXPECT SPEED CHANGE

AT (position) R UM101 AT (position)

EXPECT (speed) N/A

SPDU -3 Notification that a speed

instruction may be issued to take

effect at the specified level. EXPECT SPEED CHANGE

AT (level single) R UM102 AT (altitude)

EXPECT (speed) N/A

SPDU -4 Instruction to maintain the

specified speed. MAINTAIN (speed) W/U UM106 MAINTAIN

(speed) UM106 MAINTAIN

(speed)

SPDU -5 Instruction to maintain the

present speed. MAINTAIN PRESENT

SPEED W/U UM107 MAINTAIN

PRESENT SPEED UM107 MAINTAIN

PRESENT SPEED

SPDU -6 Instruction to maintain the

specified speed or a greater. MAINTAIN (speed) OR

GREATER W/U UM108 MAINTAIN

(speed) OR

GREATER UM108 MAINTAIN

(speed) OR

GREATER

SPDU -7 Instruction to maintain the

specified speed or a less. MAINTAIN (speed) OR

LESS W/U UM109 MAINTAIN

(speed) OR LESS UM109 MAINTAIN

(speed) OR LESS

SPDU -8 Instruction to maintain the

specified speed range. MAINTAIN (speed) TO

(speed) W/U UM110 MAINTAIN

(speed) TO (speed) N/A

SPDU -9 Instruction that the present

speed is to be increased to the

specified speed and maintained

until further advised. INCREASE SPEED TO

(speed) W/U UM111 INCREASE

SPEED TO (speed) N/A

F-28

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPDU -10 Instruction that the present

speed is to be increased to the

specified speed or greater, and maintained at or above the specified speed until further

advised. INCREASE SPEED TO

(speed) OR GREATER W/U UM112 INCREASE

SPEED TO (speed)

OR GREATER N/A

SPDU -11 Instruction that the present

speed is to be reduced to the specified speed and maintained

until further advised. REDUCE SPEED TO (speed) W/U UM113 REDUCE

SPEED TO (speed) N/A

SPDU -12 Instruction that the present

speed is to be reduced to the

specified speed or less and

maintained at or below the specified speed until further

advised. REDUCE SPEED TO (speed)

OR LESS W/U UM114 REDUCE

SPEED TO (speed)

OR LESS N/A

SPDU -13 Instruction to resume a normal

speed. The aircraft no longer needs to comply with a previously issued speed

restriction. RESUME NORMAL SPEED W/U UM116 RESUME

NORMAL SPEED UM116 RESUME

NORMAL SPEED

SPDU -14 Indication that the preferred

speed may be flown without

restriction. NO SPEED RESTRICTION R UM169 ‘NO SPEED

RESTRICTION’ UM222 NO SPEED

RESTRICTION

F-29

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPDU -15 Request to report the speed

defined by the speed type(s). REPORT (speed types)

SPEED Y UM134 CONFIRM

SPEED

Note: NE response

attribute.

UM169 ‘REPORT

GROUND SPEED’

Note 1: Used when the

controller is

requesting the pilot to

report the present

ground speed.

Note 2: R response

attribute. N/A

SPDU -16 Request to confirm the assigned

speed. CONFIRM ASSIGNED

SPEED Y UM136 CONFIRM

ASSIGNED SPEED Note: NE response

attribute. N/A

SPDU -17 Request for the earliest time or

position when the specified

speed can be accepted. WHEN CAN YOU ACCEPT

(speed) Y UM151 WHEN CAN

YOU ACCEPT

(speed)

Note: NE response

attribute. N/A

F-30

10/3/17 AC 90 -117

Appendix F

Table F -12. Speed Downlink Messages (SPDD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPDD -1 Request for the specified speed. REQUEST (speed) Y DM18 REQUEST

(speed) DM18 REQUEST

(speed)

SPDD -2 Request for the earliest time or

position that the specified speed

can be expected. WHEN CAN WE EXPECT

(speed) Y DM49 WHEN CAN WE

EXPECT (speed) N/A

SPDD -3 Report indicating the speed

defined by the specified speed

types. (speed types) SPEED (speed) N DM34 PRESENT

SPEED (speed)

DM67 ‘GROUND

SPEED (speed) ’

Note 1: Used when the

controller is requesting

the pilot to report the

present ground speed.

Note 2: When

pre-formatting of the

downlink message is not

available, the pilot can

shorten to GS (speed). N/A

SPDD -4 Confirmation that the assigned

speed is the specified speed. ASSIGNED SPEED (speed) N DM39 ASSIGNED

SPEED (speed) N/A

SPDD -5 Indication that the specified

speed can be accepted at the

specified time. WE CAN ACCEPT (speed) AT

TIME (time) N DM67 ‘WE CAN

ACCEPT (speed) AT

TIME (time) ’ N/A

SPDD -6 Indication that the specified

speed cannot be accepted. WE CANNOT ACCEPT

(speed) N DM67 ‘WE CANNOT

ACCEPT (speed) ’ N/A

F-31

10/3/17 AC 90 -117

Appendix F

Table F -13. Air Traffic Advisory Uplink Messages (ADVU )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

ADVU -1 Advisory providing the specified

altimeter setting for the

specified facility. (facility designation)

ALTIMETER (altimeter

setting) R UM153 ALTIMETER

(altimeter)

Note: The facility

designation and the

time of measurement

cannot be provided.

UM169 ‘ (facility

designation)

ALTIMETER

(altimeter setting) ’ UM213 (facility

designation)

ALTIMETER

(altimeter)

Note: The facility

designation is always

provided and the time

of measurement

cannot be provided.

ADVU -2 Advisory that the ATS

surveillance service is

terminated. SURVEILLANCE SERVICE

TERMINATED R UM154 RADAR

SERVICES

TERMINATED

UM169

‘SURVEILLANCE

SERVICE

TERMINATED’

Note: ATS advisory

that the radar and/or

ADS-B service is

terminated. N/A

ADVU -3 Advisory that ATS surveillance

service has been established. A

position may be specified

position. IDENTIFIED (position[O]) R UM155 RADAR

CONTACT (position)

Note: The provision of

the position is

required. N/A

ADVU -4 Advisory that ATS surveillance

contact has been lost. IDENTIFICATION LOST R UM156 RADAR

CONTACT LOST N/A

F-32

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

ADVU -5 ATS advisory that the current

ATIS code is as specified. ATIS (ATIS code) R UM158 ATIS

(ATIS code)

Note: The airport is

not provided. N/A

ADVU -6 Advisory to request again with

next ATC unit. REQUEST AGAIN WITH

NEXT ATC UNIT N UM169 ‘REQUEST

AGAIN WITH NEXT

ATC UNIT’

Note: R response

attribute. UM237 REQUEST

AGAIN WITH NEXT ATC UNIT

ADVU -7 Advisory of traffic significant to

the flight. TRAFFIC IS

(traffic description) R UM169 ‘TRAFFIC IS

(traffic description) ’ N/A

ADVU -8 Instruction to report that the

specified traffic has been visually sighted and passed. The

instruction may indicate the

estimated time of passing. REPORT SIGHTING AND

PASSING OPPOSITE

DIRECTION

(aircraft type[O])

(traffic location)

(ETP time[O]) W/U UM169 ‘REPORT

SIGHTING AND

PASSING OPPOSITE

DIRECTION

(traffic description)

(ETP (time)) ’

Note: ETP Time is

included when

available. N/A

ADVU -9 Instruction to select the

specified SSR code. SQUAWK (SSR code) W/U UM123 SQUAWK

(beacon code) UM123 SQUAWK

(code)

ADVU -10 Instruction to disable SSR

transponder responses. STOP SQUAWK W/U UM124 STOP

SQUAWK N/A

ADVU -11 Instruction to stop ADS -B

transmissions. STOP ADS -B

TRANSMISSION W/U UM169 ‘STOP ADS -B

TRANSMISSION’

Note: R response

attribute. N/A

ADVU -12 Instruction to include level

information in the SSR

transponder responses. SQUAWK MODE C W/U UM125 SQUAWK

ALTITUDE N/A

F-33

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

ADVU -13 Instruction to stop including

level information in the SSR

transponder responses. STOP SQUAWK MODE C W/U UM126 STOP

ALTITUDE

SQUAWK N/A

ADVU -14 Request to confirm the selected

SSR code. CONFIRM SQUAWK CODE Y UM144 CONFIRM

SQUAWK

Note: NE response

attribute. N/A

ADVU -15 Instruction that the ‘ident’

function on the SSR transponder

is to be actuated. SQUAWK IDENT W/U UM179 SQUAWK

IDENT UM179 SQUAWK

IDENT

ADVU -16 Instruction to activate the ADS -

C capability. ACTIVATE ADS -C W/U UM169 ‘ACTIVATE

ADS C ’

Note: R response

attribute. N/A

ADVU -17 Instruction to transmit voice

position reports, as specified,

due to ADS -C being out of

service. ADS -C OUT OF SERVICE

REVERT TO VOICE

POSITION REPORTS W/U UM169 ‘ADS -C OUT

OF SERVICE

REVERT TO CPDLC

POSITION

REPORTS’

UM169 ‘ADS -C OUT

OF SERVICE

REVERT TO VOICE

POSITION

REPORTS’

Note: R response

attribute. N/A

ADVU -18 Instruction to intermediary

aircraft to relay the specified

message to the specified aircraft

on the specified frequency,

when provided. RELAY TO

(aircraft identification)

(unit name) (relay text)

(frequency[O]) W/U UM169 ‘RELAY TO

(call sign) (unit name)

(text of message to be

relayed) ((frequency))’

Note 1: R response

attribute. N/A

F-34

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

Note 2: Frequency is

included when

available.

ADVU -19 Request to check the aircraft

lateral position, level or speed,

due to the ATC unit detecting a

deviation from the clearance. (deviation type) DEVIATION

DETECTED. VERIFY AND

ADVISE W/U UM169 ‘LATERAL

POSITION

DEVIATION

DETECTED. VERIFY

AND ADVISE’

UM169 ‘LEVEL

DEVIATION

DETECTED. VERIFY

AND ADVISE’

UM169 ‘SPEED

DEVIATION

DETECTED. VERIFY

AND ADVISE’

Note: R response

attribute. N/A

ADVU -20 Notification that the CPDLC

transfer is expected at the

specified time. EXPECT CPDLC

TRANSFER AT TIME (time) R UM169 ‘EXPECT

CPDLC TRANSFER AT TIME (time) ’

Note: R response

attribute. N/A

ADVU -21 Notification that the first

specified ATS U will not

establish CPDLC and the NDA

is expected to be the second

specified ATS U. CPDLC WITH (unit name)

NOT REQUIRED EXPECT

NEXT CPDLC FACILITY

(unit name) R UM169 CPDLC WITH

(unit name) NOT

REQUIRED EXPECT

NEXT CPDLC

FACILITY (unit name)

Note: R response

attribute. N/A

F-35

10/3/17 AC 90 -117

Appendix F

Table F -14. Air Traffic Advisory Downlink Messages (ADVD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

ADVD -1 Report indicating that the aircraft

is squawking the specified SSR

code. SQUAWKING (SSR code) N DM47 SQUAWKING

(code) N/A

ADVD -2 Report indicating that whether or

not traffic has been visually

sighted and if so, if it has been

passed. May provide a description and/or location of the

aircraft. TRAFFIC (aircraft type[ O])

(traffic location)

(traffic visibility) N DM67 ‘ (traffic

identification) SIGHTED

AND PASSED’

DM67 ‘ (traffic

identification) NOT

SIGHTED’

DM67 ‘TRAFFIC

SIGHTED’ N/A

F-36

10/3/17 AC 90 -117

Appendix F

Table F-15. Voice Communication Uplink Messages (COMU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

COMU -1 Instruction to establish voice

contact with the specified ATSU

on the specified frequency. CONTACT (unit name)

(frequency) W/U UM117 CONTACT

(ICAO unit name)

(frequency) UM117 CONTACT

(unit name)

(frequency)

COMU -2 Instruction at the specified

position, to establish voice

contact with the specified ATSU

on the specified frequency. AT (position) CONTACT

(unit name) (frequency) W/U UM118 AT (position)

CONTACT (ICAO unit

name) (frequency) N/A

COMU -3 Instruction at the specified time,

to establish voice contact with the specified ATSU on the

specified frequency. AT TIME (time) CONTACT

(unit name) (frequency) W/U UM119 AT (time)

CONTACT (ICAO unit

name) (frequency) N/A

COMU -4 Advisory of the secondary

frequency. SECONDARY FREQUENCY

(frequency) R UM169

‘SECONDARY FREQUENCY

(frequency) ’ N/A

COMU -5 Instruction to monitor the

specified ATSU on the specified

frequency. The pilot is not

required to establish voice

contact on the frequency. MONITOR (unit name)

(frequency) W/U UM120 MONITOR

(ICAO unit name)

(frequency) UM120 MONITOR

(unit name) (frequency)

COMU -6 Instruction at the specified

position, to monitor the

specified ATSU on the specified

frequency. The pilot is not

required to establish voice

contact on the frequency. AT (position) MONITOR

(unit name) (frequency) W/U UM121 AT (position)

MONITOR (ICAO unit

name) (frequency) N/A

F-37

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

COMU -7 Instruction that at the specified

time, to monitor the specified

ATSU on the specified

frequency. The pilot is not

required to establish voice

contact on the frequency. AT TIME (time) MONITOR

(unit name) (frequency) W/U UM122 AT (time)

MONITOR (ICAO unit

name) (frequency) N/A

COMU -8 Instruction to check the

microphone due to detection of a

continuous transmission on the

specified frequency. CHECK STUCK

MICROPHONE (frequency) N UM157 CHECK

STUCK

MICROPHONE

(frequency)

Note: R response

attribute . UM157 CHECK

STUCK

MICROPHONE

(frequency)

COMU -9 Advisory of the name of the

current ATC unit. CURRENT ATC UNIT

(unit name) N N/A UM183 ‘CURRENT

ATC UNIT

(unit name) ’

F-38

10/3/17 AC 90 -117

Appendix F

Table F -16. Voice Communication Downlink Messages (COMD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

COMD -1 Request for voice contact on the

specified frequency. REQUEST VOICE CONTACT

(frequency) Y DM20 REQUEST

VOICE CONTACT

Note: Used when a

frequency is not required.

DM21 REQUEST

VOICE CONTACT

(frequency)

Note: Used when a

frequency is required . N/A

COMD -2 Notification from the

intermediary aircraft of the

specified response from the

specified aircraft. RELAY FROM

(aircraft identification)

(relayed text response) N DM67 ‘RELAY FROM

(call sign) (response parameters) ’ N/A

F-39

10/3/17 AC 90 -117

Appendix F

Table F-17. Spacing Uplink Messages (SPCU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPCU -1 ATS acknowledgement for the

pilot use of the in -trail procedure

when the ITP aircraft is behind

the reference aircraft. This

message element is always

concatenated with a vertical

clearance. ITP BEHIND

(aircraft identification) N UM169 ‘ITP BEHIND

(aircraft identification) ’

Note: R response attribute. N/A

SPCU -2 ATS acknowledgement for the

pilot use of the in -trail procedure

when the ITP aircraft is ahead of

the reference aircraft. This message element is always concatenated with a vertical

clearance. ITP AHEAD OF

(aircraft identification) N UM169 ‘ITP AHEAD

OF (aircraft

identification) ’

Note: R response attribute. N/A

SPCU -3 ATS acknowledgement for the

pilot use of the in -trail procedure

when the ITP aircraft is behind

both reference aircraft. This

message element is always

concatenated with a vertical

clearance. ITP BEHIND (aircraft

identification) AND BEHIND

(aircraft identification) N UM169 ‘ITP BEHIND

(aircraft identification)

AND BEHIND

(aircraft

identification) ’

Note: R response

attribute. N/A

SPCU -4 ATS acknowledgement for the

pilot use of the in -trail procedure

when the ITP aircraft is ahead of

both reference aircraft. This message element is always

concatenated with a vertical

clearance. ITP AHEAD OF (aircraft

identification) AND AHEAD

OF (aircraft identification) N UM169 ‘ITP AHEAD

OF (aircraft

identification) AND

AHEAD OF (aircraft

identification) ’

Note: R response

attribute. N/A

F-40

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPCU -5 ATS acknowledgement for the

pilot use of the in -trail procedure

when the ITP aircraft is behind

one reference aircraft and ahead of one reference aircraft. This message element is always

concatenated with a vertical

clearance. ITP BEHIND (aircraft

identification) AND AHEAD

OF (aircraft identification) N UM169 ‘ITP BEHIND

(aircraft identification)

AND AHEAD OF

(aircraft identification) ’

Note: R response

attribute. N/A

F-41

10/3/17 AC 90 -117

Appendix F

Table F-18. Spacing Downlink Messages (SPCD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPCD -1 Advisory indicating that the pilot

has the ITP equipment, and

provides the specified distance to

the reference aircraft, including

aircraft identification. This

message element is always

concatenated with a vertical

request. ITP (specified distance)

BEHIND (aircraft

identification) N DM67 ‘ITP (distance)

BEHIND (aircraft

identification) ’ N/A

SPCD -2 Advisory indicating that the pilot

has the ITP equipment, and

provides the specified distance from the reference aircraft, including aircraft identification.

This message element is always

concatenated with a vertical

request. ITP (specified distance)

AHEAD OF (aircraft

identification) N DM67 ‘ITP (distance)

AHEAD OF (aircraft

identification) ’ N/A

SPCD -3 Advisory indicating that the pilot

has the ITP equipment, and

provides the specified distance to

both reference aircraft, including

aircraft identification. This

message element is always

concatenated with a vertical

request. ITP (specified distance)

BEHIND (aircraft

identification) AND (specified

distance) BEHIND (aircraft

identification) N DM67 ‘ITP (distance)

BEHIND (aircraft

identification ) AND

(distance) BEHIND

(aircraft identification')’

Note: Used with a

vertical request,

indicating an ITP request

when there are two reference aircraft, both

behind. N/A

F-42

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SPCD -4 Advisory indicating that the pilot

has the ITP equipment, and

provides the specified distance from both reference aircraft, including aircraft identification.

This message element is always

concatenated with a vertical request. ITP (specified distance)

AHEAD OF (aircraft

identification) AND (specified

distance) AHEAD OF (aircraft

identification) N DM67 ‘ITP (distance)

AHEAD OF (aircraft

identification) AND

(distance) AHEAD OF

(aircraft identification)’

Note: Used with a vertical request,

indicating an ITP request

when there are two reference aircraft, both

ahead. N/A

SPCD -5 Advisory indicating that the pilot

has the ITP equipment, and

provides the specified distance to

one reference aircraft and the specified distance from another reference aircraft, including aircraft identification. This message element is always

concatenat ed with a vertical

request. ITP (specified distance)

BEHIND (aircraft

identification) AND (specified

distance) AHEAD OF (aircraft

identification) N DM67 ‘ITP (distance)

BEHIND (aircraft

identification) AND

(distance) AHEAD OF

(aircraft identification)’

Note: Used with a

vertical request,

indicating an ITP request

when there are two

reference aircraft, one behind and the other

ahead. N/A

F-43

10/3/17 AC 90 -117

Appendix F

Table F -19. Emergency/Urgency Uplink Messages (EMGU )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

EMGU -1 Request to provide the fuel

remaining (time) and the

number of persons on board. REPORT ENDURANCE

AND PERSONS ON BOARD Y UM131 REPORT

REMAINING FUEL

AND SOULS ON

BOARD

Note: NE response

attribute. N/A

EMGU -2 Instruction to immediately

comply with the associated

instruction to avoid imminent

situation. IMMEDIATELY N Used in combination

with LVLU -6 and

LVLU -9, which is

implemented in

FANS 1/A as:

UM38 IMMEDIATELY

CLIMB TO (altitude)

UM39

IMMEDIATELY

DESCEND TO

(altitude) N/A

EMGU -3 Request to confirm an ADS - C

indicated emergency. CONFIRM ADS -C

EMERGENCY A/N UM169 ‘CONFIRM

ADS -C

EMERGENCY’

Note: R response

attribute. N/A

F-44

10/3/17 AC 90 -117

Appendix F

Table F -20. Emergency/Urgency Downlink Messages (EMGD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

EMGD -1 Indication of an urgent situation. PAN PAN PAN Y DM55 PAN PAN PAN

Note: N response

attribute. N/A

EMGD -2 Indication of an emergency

situation. MAYDAY MAYDAY

MAYDAY Y DM56 MAYDAY

MAYDAY MAYDAY

Note: N response

attribute. N/A

EMGD -3 Report indicating fuel remaining

(time) and number of persons on

board. (remaining fuel)

ENDURANCE AND (persons

on board) PERSONS ON

BOARD Y DM57 (remaining fuel)

OF FUEL REMAINING

AND (remaining souls)

SOULS ON BOARD

Note: N response

attribute. N/A

EMGD -4 Indication that the emergency

situation is cancelled. CANCEL EMERGENCY Y DM58 CANCEL

EMERGENCY

Note: N response

attribute. N/A

F-45

10/3/17 AC 90 -117

Appendix F

Table F-21. Standard Response Uplink Messages (RSPU )

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RSPU -1 Indication that the message

cannot be complied with. UNABLE N UM0 UNABLE UM0 UNABLE

RSPU -2 Indication that the message will

be responded to shortly. STANDBY N UM1 STANDBY UM1 STANDBY

RSPU -3 Indication that a long term delay

in response can be expected. REQUEST DEFERRED N UM2 REQUEST

DEFERRED N/A

RSPU -4 Indication that the message is

received. ROGER N UM3 ROGER

UM169 ‘ROGER

MAYDAY’

Note 1: R response attribute.

Note 2 : Used to

acknowledge emergency downlink

reports.

UM169 ‘ROGER

PAN’

Note 1: R response

attribute.

Note 2 : Used to

acknowledge urgency

downlink reports . UM3 ROGER

RSPU -5 Indication that ATC is

responding positively to the

message. AFFIRM N UM4 AFFIRM UM4 AFFIRM

RSPU -6 Indication that ATC is

responding negatively to the

message. NEGATIVE N UM5 NEGATIVE UM5 NEGATIVE

F-46

10/3/17 AC 90 -117

Appendix F

Operational Definition in PANS- ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RSPU -7 Indication that the request has

been forwarded to the next

control unit. REQUEST FORWARDED N UM169 ‘REQUEST

FORWARDED’

Note: R response

attribute. UM211 REQUEST

FORWARDED

RSPU -8 Request to confirm the referenced request since the

initial request was not

understood. The request should

be clarified and resubmitted. CONFIRM REQUEST N UM143 CONFIRM

REQUEST N/A

Table F -22. Standard Response Downlink Messages (RSPD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

RSPD -1 Indication that the instruction is

understood and will be complied

with. WILCO N DM0 WILCO DM0 WILCO

RSPD -2 Indication that the instruction

cannot be complied with. UNABLE N DM1 UNABLE DM1 UNABLE

RSPD -3 Indication that the message will

be responded to shortly. STANDBY N DM2 STANDBY DM2 STANDBY

RSPD -4 Indication that the message is

received. ROGER N DM3 ROGER

Note: ROGER is the only

correct response to an

uplink free text message. DM3 ROGER

RSPD -5 Indication of a positive response

to a message. AFFIRM N DM4 AFFIRM DM4 AFFIRM

RSPD -6 Indication of a negative response

to a message. NEGATIVE N DM5 NEGATIVE DM5 NEGATIVE

F-47

10/3/17 AC 90 -117

Appendix F

Table F -23. Supplemental Uplink Messages (SUPU )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SUPU -1 Indication that the associated

instruction is to be executed

when the pilot is ready. WHEN READY N UM164 WHEN

READY N/A

SUPU -2 Indication that the associated

message is issued due to the

specified reason. DUE TO (specified reason

uplink) N UM166 DUE TO

TRAFFIC

UM167 DUE TO

AIRSPACE

RESTRICTION N/A

SUPU -3 Instruction to execute the

associated instruction at the

aircraft’s best performance rate. EXPEDITE N Used in combination

with LVLU -6, which is

implemented in FANS

1/A as:

UM36 EXPEDITE

CLIMB TO (altitude) . N/A

SUPU -4 Indication that the associated

instruction is either a revision to a previously issued instruction

or is different from the requested

clearance. REVISED

(revision reason[O]) N UM170 ‘REVISED

(revision reason[O]) ’

Note: R response

attribute. N/A

SUPU -5 Indication that the associated

instruction is to be executed at

the earliest point when the pilot

is able. WHEN ABLE N N/A

Note: This message

element is part of

UM75. N/A

F-48

10/3/17 AC 90 -117

Appendix F

Table F -24. Supplemental Downlink Messages (SUPD )

Operational Definition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SUPD -1 Indication that the associated

message is issued due to

specified reason. DUE TO (specified reason

downlink) N DM65 DUE TO

WEATHER DM65 DUE TO

WEATHER

SUPD -1 Indication that the associated

message is issued due to

specified reason. DUE TO (specified reason

downlink) N DM66 DUE TO

AIRCRAFT

PERFORMANCE DM66 DUE TO

AIRCRAFT

PERFORMANCE

Table F -25. Free Text Uplink Messages (TXTU )

Operational D efinition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

TXTU -1 (free text)

Note: M alert attribute. R UM169 (free text) UM203 (free text)

TXTU -2 (free text)

Note: M alert attribute. N UM169 (free text)

Note: R response

attribute. UM183 (free text)

TXTU -3 (free text)

Note: N alert attribute. N UM169 (free text)

Note: R response

attribute. N/A

TXTU -4 (free text)

Note: M alert attribute. W/U UM169 (free text)

Note: R response

attribute. UM196 (free text)

TXTU -5 (free text)

Note: M alert attribute. A/N UM169 (free text)

Note: R response

attribute. UM205 (free text)

F-49

10/3/17 AC 90 -117

Appendix F

Table F-26. Free Text Downlink Messages (TXTD )

Operational D efinition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended Use Format for Message Element

Display Resp. FANS 1/A ATN B1

TXTD -1 (free text)

Note: M alert attribute. Y DM68 (free text)

Note 1: Urgency or

Distress Alr (M).

Note 2: Selecting any of

the emergency message

elements will result in

this message element

being enabled for the

pilot to include in the

emergency message at

their discretion. N/A

TXTD -2 (free text)

Note: M alert attribute. N DM67 (free text) DM98 (free text)

F-50

10/3/17 AC 90 -117

Appendix F

Table F-27. System Management Uplink Messages (SYSU )

Operational D efinition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SYSU -1 System -generated notification

of an error. ERROR (error information) N UM159 ERROR

(error information) UM159 ERROR

(error information)

SYSU -2 System -generated notification

of the next data authority or the

cancellation thereof. NEXT DATA AUTHORITY

(facility designation[O]) N UM160 NEXT

DATA AUTHORITY (ICAO facility designation)

Note: The facility designation is

required. UM160 NEXT DATA

AUTHORITY

(facility)

Note: Facility parameter can

specify a facility designation

or no facility.

SYSU -3 System -generated notification

that received message is not

supported. MESSAGE NOT SUPPORTED BY THIS ATC

UNIT N UM169 ‘MESSAGE

NOT SUPPORTED BY THIS ATC

UNIT’

Note: R response

attribute. UM162 MESSAGE NOT

SUPPORTED BY THIS

ATS UNIT

SYSU -4 System -generated notification

that the received is acceptable

for display. LOGICAL

ACKNOWLEDGEMENT N N/A UM227 LOGICAL

ACKNOWLEDGEMENT

SYSU -5 System -generated message

indicating that requests for logical acknowledgements are

not permitted. USE OF LOGICAL

ACKNOWLEDGEMENT

PROHIBITED N N/A UM233 USE OF LOGICAL

ACKNOWLEDGEMENT PROHIBITED

Note: ATN B1 ground

systems may not use UM

(as par ETSI CS) since the

use of LACK is required.

F-51

10/3/17 AC 90 -117

Appendix F

Operational D efinition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SYSU -6 Advisory providing the

maximum one -way uplink

message transmission delay. LATENCY TIME VALUE

(latency value) N UM169 ‘SET MAX

UPLINK DELAY

VALUE TO (delayed message parameter)

SECONDS’

Note 1: R response

attribute.

Note 2: On FANS 1/A

aircraft, this message requires specific action from the pilot to manually set the

latency value. N/A

SYSU -7 Indication that the received

message has a latency greater

than the requirement. MESSA GE RECEIVED TOO

LATE, RESEND MESSAGE OR CONTACT BY VOICE N N/A UM159 ERROR

(error information) +

UM183 ‘DOWNLINK

DELAYED USE – VOICE’

Note: The error information

is set to the value (2).

F-52

10/3/17 AC 90 -117

Appendix F

Table F -28. System Management Downlink Messages (SYSD )

Operational D efinition in PANS -ATM (Doc 4444) CPDLC Message Sets

Message Element

Identifier Message Element Intended

Use Format for Message Element

Display Resp. FANS 1/A ATN B1

SYSD -1 System -generated notification

of an error. ERROR (error information) N DM62 ERROR

(error information) DM62 ERROR

(error information)

SYSD -2 System -generated notification

that the received message is

acceptable for display. LOGICAL

ACKNOWLEDGEMENT N N/A DM100 LOGICAL

ACKNOWLEDGEMENT

SYSD -3 System -generated rejection of

any CPDLC message sent

from a ground facility that is

not the current data authority. NOT CURRENT DATA

AUTHORITY N DM63 NOT CURRENT

DATA AUTHORITY DM63 NOT CURRENT

DATA AUTHORITY

SYSD -4 System -generated notification

that the ground facility is now

the current data authority. CURRENT DATA

AUTHORITY N N/A DM99 CURRENT DATA

AUTHORITY

SYSD -5 System -generated notification

that the ground system is not

designated as the next data

authority (NDA), indicating

the identity of the Current

Data Authority. Identity of the

Next Data Authority, if any, is

also reported. NOT AUTHORIZED NEXT

DATA AUTHORITY

(facility designation)

(facility designation[O]) N DM64 (ICAO facility

designation)

Note: Use by FANS 1/A

aircraft in B1

environments. DM107 NOT AUTHORIZED

NEXT DATA AUTHORITY

Note: CDA and NDA cannot be

provided.

SYSD -6 Indication that the received

message has a latency greater

than the requirement. MESSAGE RECEIVED TOO

LATE, RESEND MESSAGE OR CONTACT BY VOICE N DM67 ‘MESSAGE

RECEIVED TOO LATE, RESEND

MESSAGE OR

CONTACT BY

VOICE’

Note: Sent with DM62. DM 98 ‘MESSAGE

RECEIVED TOO LATE,

RESEND MESSAGE OR

CONTACT BY VOICE’

Note: Sent with DM62.

SYSD -7 System -generated notification

that the aircraft is in the

inhibited state. AIRCRAFT CPDLC

INHIBITED N N/A DM 98 ‘AIRCRAFT CPDLC

INHIBITED'

F-53

10/3/17 AC 90 -117

Appendix F

Table F-29. FANS 1/A Uplink Messages Not Recommended for Use

Message Element Justification

UM49 CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message due to inability of aircraft automation to maintain

the altitude restriction.

UM62 AT (time) CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message due to inability of aircraft automation to maintain the altitude restriction.

UM85 EXPECT (route clearance) Avoid use of this message element due to potenti al misinterpretation.

UM86 AT (position) EXPECT (route clearance) Avoid use of this message element due to potential misinterpretation.

UM87 EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.

UM88 AT (position) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.

UM89 AT (time) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.

UM90 AT (altitude) EXPECT DIRECT TO (position) Avoid use of this message element due to potential misinterpretation.

UM162 SERVICE UNAVAILABLE Avoid use of this message element due to potential misinterpretation.

UM6 EXPECT (altitude) Avoid use of this message element due to potential misinterpretation.

UM11 EXPECT CRUISE CLIMB AT (time) Avoid use of this message element due to potential misinterpretation.

UM12 EXPECT CRUISE CLIMB AT (position) Avoid use of this message element due to potential misinterpretation.

UM13 A T (time) EXPECT CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.

UM14 AT (position) EXPECT CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.

UM15 AT (time) EXPECT DESCENT TO (altitude) Avoid use of this message element due to potential misinterpretation.

UM16 AT (position) EXPECT DESCENT TO (altitude) Avoid use of this message element due to potential misinterpretation.

UM17 AT (time) EXPECT CRUISE CLIMB T O (altitude) Avoid use of this message element due to potential misinterpretation.

UM49 CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.

UM62 AT (time) CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.

UM18 AT (position) EXPECT CRUISE CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.

UM33 CRUISE (altitude) Avoid use of this message element due to potential misinterpretation.

UM34 CRUISE CLIMB TO (altitude) Avoid use of this message element due to potential misinterpretation.

F-54

10/3/17 AC 90 -117

Appendix F

Message Element Justification

UM35 CRUISE CLIMB ABOVE (altitude) Avoid use of this message element due to potential misinterpretation.

UM40 IMMEDIATELY STOP CLIMB AT (altitude) Avoid use of this message element due to potential misinterpretation.

UM41 IMMEDIATELY STOP DESCENT AT (altitude) Avoid use of this message element due to potential misinterpretation.

UM175 REPORT REACHING (altitude) Avoid use of this message element due to potential misinterpretation.

UM42 EXPECT TO CROSS (position) AT (altitude) Avoid use of this message element due to potential misinterpretation.

UM43 EXPECT TO CROSS (position) AT OR ABOVE (altitude) Avoid use of this message element due to potential misinterpretation.

UM44 EXPECT TO CROSS (position) AT OR BELOW (altitude) Avoid use of this message element due to potential misinterpretation.

UM45 EXPECT TO CROSS (position) AT AND MAINTAIN (altitude) Avoid use of this message element due to potential misinterpretation.

UM103 AT (time) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.

UM104 AT (position) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.

UM105 AT (altitude) EXPECT (speed) TO (speed) Avoid use of this message element due to potential misinterpretation.

UM165 THEN Avoid use of this message element due to potential misinterpretation.

UM235 ROGER 7500 Avoid use of this message element due to potential misinterpretation.

UM168 DISREGARD Not operationally required.

Note: These messages have been excluded from future B2 implementation .

UM176 MAINTAIN OWN SEPARATION AND VMC Not operationally required.

Note : These messages have been excluded from future B2 implementation .

UM152 WHEN CAN YOU ACCEPT (specified distance) (direction) OFFSET Not operationally required.

Note : These messages have been excluded from future B2 implementation .

UM115 DO NOT EXCEED (speed) Not operationally required.

Note : These messages have been excluded from future B2 implementation .

UM182 CONFIRM ATIS CODE Not operationally required.

Note : These messages have been excluded from future B2 implementation .

UM169 ‘TRANS MIT ADS -B IDENT’ Use of SQUAWK IDENT is recommended.

UM169 ‘IDENTIFICATION TERMINATED’ Use of SURVEILLANCE SERVICE TERMINATED is recommended.

UM132 CONFIRM POSITION Use of ADS -C is recommended.

UM133 CONFIRM ALTITUDE Use of ADS -C is recommended.

F-55

10/3/17 AC 90 -117

Appendix F

Message Element Justification

UM138 CONFIRM TIME OVER REPORTED WAYPOINT. Use of ADS -C is recommended.

UM139 CONFIRM REPORTED WAYPOINT Use of ADS -C is recommended.

UM140 CONFIRM NEXT WAYPOINT Use of ADS -C is recommended.

UM141 CONFIRM NEXT WAYPOINT ETA. Use of ADS -C is recommended.

UM142 CONFIRM ENSUING WAYPOINT Use of ADS -C is recommended.

UM146 REPORT GROUND TRACK Use of ADS -C is recommended.

UM181 REPORT DISTANCE (to/from) (position) Use of ADS -C is recommended.

UM145 CONFIRM HEADING Use of ADS -C is recommended.

UM177 AT PILOTS DISC RETION Not globally accepted. In airspace managed by the United States, when the

controller issues UM177 AT PILOTS DISCRETION in conjunction with

altitude assignments, the associated instruction to climb or descend may be executed when convenient and at any preferred rate. The aircraft may

temporarily maintain intermediate levels but once the aircraft has vacated a

level it may not return to that level.

F-56

10/3/17 AC 90 -117

Appendix F

Table F -30. FANS 1/A Downlink Messages Not Recommended for Use

Message Element Justification

DM69 REQUEST VMC DESCENT Avoid use of this message element due to potential misinterpretation

DM75 AT PILOTS DISCRETION Avoid use of this message element due to potential misinterpretation

DM 67 ‘WHEN CAN WE EXPECT DESCENT TO (altitude) ’ Avoid use of this message due to potential misinterpretation of subsequent

response. Use of LVLD -6 WHEN CAN WE EXPECT LOWER LEVEL and

LVLD -7 WHEN CAN WE EXPECT HIGHER LEVEL is recommended.

DM67 ‘WHEN CAN WE EXPECT CLIMB TO (altitude) ’ Avoid use of this me ssage due to potential misinterpretation of subsequent

response. Use of LVLD -6 WHEN CAN WE EXPECT LOWER LEVEL and

LVLD -7 WHEN CAN WE EXPECT HIGHER LEVEL is recommended.

DM74 REQUEST TO MAINTAIN OWN SEPARATION AND VMC Not operationally required.

Note: Thes e messages have been excluded from future B2 implementation.

DM8 REQUEST CRUISE CLIMB TO (altitude) Not operationally required.

Note: These messages have been excluded from future B2 implementation.

DM54 WHEN CAN WE EXPECT CRUISE CLIMB TO (altitude) Not operationally required.

Note: These messages have been excluded from future B2 implementation.

DM72 REACHING (altitude) Not operationally required.

Note: These messages have been excluded from future B2 implementation.

DM79 ATIS (ATIS code) Not operation ally required.

Note: These messages have been excluded from future B2 implementation.

DM67 ‘MONITORING (unit name) (frequency) ’ Not operationally required.

Note: These messages have been excluded from future B2 implementation.

DM16 AT (position) REQUEST OFFSET (specified distance) (direction) OF

ROUTE Not operationally required.

Note: These messages have been excluded from future B2 implementation.

DM17 AT (time) REQUEST OFFSET (specified distance) (direction) OF

ROUTE Not operationally required .

Note: These messages have been excluded from future B2 implementation.

DM26 REQUEST WEATHER DEVIATION TO (position) VIA

(route clearance) Not operationall y required.

Note: These messages have been excluded from future B2 implementation.

DM33 PRESENT PO SITION (position) Use of ADS -C is recommended.

DM36 PRESENT GROUND TRACK (degrees) Use of ADS -C is recommended.

F-57

10/3/17 AC 90 -117

Appendix F

Message Element Justification

DM42 NEXT WAYPOINT (position) Use of ADS -C is recommended.

DM43 NEXT WAYPOINT ETA (time) Use of ADS -C is recommended.

DM44 ENSUING WAYPOINT (position) Use of ADS -C is recommended.

DM45 REPORTED WAYPOINT (position) Use of ADS -C is recommended.

DM46 REPORTED WAYPOINT (time) Use of ADS -C is recommended.

DM78 AT (time) (distance) (to/from) (position) Use of ADS -C is recommended.

DM32 PRESENT ALTITUDE (altitude) Use of ADS -C is recommended.

DM35 PRESENT HEADING (degrees) Use of ADS -C is recommended.

DM19 REQUEST (speed) TO (speed) Use of SPDD -1 REQUEST (speed) is recommended.

DM50 WHEN CAN WE EXPECT (speed) TO (speed) Use of SPD D-1 REQUEST (speed) is recommended.

Table F -31. ATN B1 Uplink Messages Not Recommended for Use

Message Element Justification

UM165 THEN Avoid use of this message element due to potential misinterpretation.

Table F-32. ATN B1 Downlink Messages Not Recommended for Use

Message Element Justification

DM89 MONITORING (unit name) (frequency) Not operationally required.

Note: This message has been excluded from future B2 implementation.

F-58

10/3/17 AC 90 -117

Appendix G

AP

PENDIX G. TERMINOLOGY AND ACRONYMS

G.

1 Terminology.

1. Aeronautical Telecommunication s Network (ATN). A global inter -network

architecture that allows ground, air-ground, and avionic data subnetworks to

exchange digital data for the safety of air navigation and for the regular, efficient, and economic operation of A ir Traffic S ervices (ATS) .

2. Air Navigation Services P rovider (ANSP) . An organization responsible for the

provision of ATS .

3. Air Traffic Data Link Service. A data communication capability comprising

air/ground and ground/ground data network services, specified data link message sets and protocols, aircraft equipment, Air Traffic Service Unit (ATS U) facility

equipment, and operational procedures intended to provide primary or supplemental ATS U communications.

4. Air Traffic Service Unit (ATSU). This domain includes the controller and the

ATSU system which consists of an end system where data communications applications reside, a ground to ground router, a ground to ground communication network, and human -machine i nterface (HMI).

5. Aircraft Communications Addressing and Reporting System (ACARS). ACARS

is a digital data link system for transmission of short messages between aircraft and

ground stations via airband radi o or satellite. ACARS as a term refers to the complete

air and ground system, consisting of a service provider and aircraft/ ground

equipment.

6. Allocations. For approval, design, and monitoring purposes, performance requirements are provided against allocated human and technical Air Traffic System Management ( ATM )/Communication, Navigation, and Surveillance ( CNS ) elements

(i.e., the aircraft system, aircraft operator, ANSP , and Communication Service

Provider (CSP)) of the data communications transaction.

7. Automatic Dependent Surveillance -Contract (ADS -C). ADS -C is a surveillance

information system using automated reports. An agreement is established between the ground system and the aircraft via a data link. Without pilot input, the ATSU can establish a “co ntract” to provide reports of aircraft position, altitude, speed, elements

of navigational intent, and meteorological data. The system can generate the following types of reports:

• Demand : An ATSU can request an update as needed, and this does not affect

an existing contact preset rate.

• Event : A change in vertical rate, lateral deviation , or altitude automatically

triggers a report.

• Periodic : The ATSU can set or alter the update rate as needed (a higher update

rate is usually required in high traffic areas or with reduced lateral separations ).

G-1

10/3/17 AC 90 -117

Appendix G

8. Availability. The probability that an operational communication transaction can be

initiated when needed.

9. Communication Transaction Time . The maximum time for the completion of the

operational communication transaction, after which the initiator should revert to an

alternative procedure.

10. Continuity. The probability that an operational communication transaction can be

completed within the communication transaction time.

11. Controller- Pilot Data Link C ommunications (CPDLC). CPDLC is a two -way

data- link communication system by which controllers can transmit digital text

messages to an aircraft as an alternative to voice communications. Messages from an aircraft to the ATSU may follow a standard format or may be free text. Mes sages

from a controller normally follow a standard format and usually require a response from the pilot .

12. Current D ata Authority (CDA). The designated ground system through which a

CPDLC dialogue between a pilot and a controller currently responsible for the flight is permitted to take place.

13. Data L ink Communication System. A data link communication system is a means

of transmitting and receiving digital information. “ Data link ” is a generic term that

encompasses different types of data link communication systems and subnetworks.

14. Departure Clearance (DCL). DCL (CPDLC -DCL) is the initial phase of

U.S. domestic airspace implementation of data commun ication and is limited to

tower services. CPDLC -DCL provides automated assistance for requesting and

delivering initial and revised DCL s using CPDLC. The DCL includes flight plan

route, climb via and/or initial/requested altitude, beacon code assig nment,

and departure frequency.

15. Downlink M essage (DM). A CPDLC message sent from an aircraft.

16. Future Air Navigation Sys tem (FANS). FANS is an avionics system which

provides direct data link communication between the pilot and the air traffic controller. The communications include air traffic control (ATC) clearances, pilot

requests , and P osition R eporting (PR).

17. Integrity. The probability of one or more undetected errors in a completed

communication transaction.

18. Maximum Accumulated U nplanned O utage T ime. A value that defines the

acceptable accumulated duration of unplanned outages that exceed the unplanned outage duration l imit in a specified time period.

Note: Unplanned outages that are less than the unplanned outage duration limit

are considered against the criterion for continuity.

G-2

10/3/17 AC 90 -117

Appendix G

19. Maximum Number of U nplanned O utages. A value that defines the acceptable

number of unplanned outa ges that exceed the unplanned outage duration limit in a

specified time period.

Note: Unplanned outages that are less than the unplanned outage duration limit

are considered against the criterion for continuity.

20. Minimum E quipment L ist (MEL). A list whic h provide s for the operation

of aircraft, subject to specified conditions, with particular equipment inoperative,

prepared by an operator in conformity with, or more restrictive than, the Master

Minimum Equipment List ( MMEL ) established for the aircraft type.

21. Next D ata Authority (NDA) . The ground system so designated by the CDA through

which an onward transfer of comm unications and control can take place.

22. Performance -Based Communication and Surveillance (PBCS) . PBCS is a concept

that applies required communication performance (RCP) and required surveillance performance (RSP) specifications to ensure appropriate performance levels for relevant ATM operations (e.g. , application of a reduced separation minimum).

23. Pre-Departure Clearance (PDC) . A PDC is a clearance that is issued in a text

format rather than being issued audibly over a clearance delivery frequency. This text

clearance is issued through the use of a data link communication computer system

and is relayed from a dispatch system to the pilot via an ACARS message or a

terminal gate printer.

24. Required C ommunication Performance (RCP) . A set of requirements for ATS

provision, aircraft capability, and operations needed to support performance -based

communication within a defined airspace.

• RCP A vailability - Aircraft (A

AIR). An RCP allocation that specifies the

required probability that the aircraft system is serviceable for the relevant communication capability.

• RCP A vailability – CSP (A

CSP). An RCP allocation that specifies the required

probability that the CSP systems are available to provide the required level of

communication service, given the ATS U’s system is available.

25. Required Surveillance P erformance (RSP). A statement of the performance

requirements for operational surveillance in s upport of specific ATM functions.

26. Satellite Communication (SAT COM ). The Aviation SATCOM is a worldwide

mobile communications system providing voice and data communications services between aircraft subnetworks and ground subnetworks.

27. Secondary Surveillance Radar (SSR). A type of radar used by ATSU to transmit

and receive data on transponder equipped aircraft. This data includes barometric

altitude and identification codes .

28. Supplemental Type Certificate (STC). An STC is a type certificate (TC) issued

when an applicant has received FAA approval to modify an aeronautical product from

its original design .

G-3

10/3/17 AC 90 -117

Appendix G

29. Surveillance Transaction Time. The surveillance transaction time specifies the

maximum time for the completion of the operational surveillance process. This

parameter is an indication of time criticality.

30. Type Certificate (TC). A TC is issued by th e FAA when the airworthiness of an

aircraft manufacturing design has been de termined to be acceptable. Once issued, the

design cannot be changed without approval from the FAA.

31. Uplink M essage (UM). A CPDLC message sent from a ground system.

G-4

10/3/17 AC 90 -117

Appendix G

G.2 Acronyms .

Acronym Meaning

4-D Four -Dimensional

4DTRAD Four -Dimensional Trajectory Data Link

14 CFR Title 14 of The Code of Federal Regulations

AC Advisory Circular

ACARS Aircraft Communication s Addressing and Reporting System

ACL Air Traffic Control Clearance

ACM Air Traffic Control Communication Management

ACP Actual Communications Performance

ACTP Actual Communication Technical Performance

AD Airworthiness Directive

ADS Automatic Dependent Surveillance

ADS -C Automatic Dependent Surveillance -Contract

AEG Aircraft Evaluation Group

AFM Airplane Flight Manual

AFN Air Traffic Service Facilities Notification

AIP Aeronautical Information Publication

AIS Aeronautical Information Service

AMC Air Traffic Control Microphone Check

ANSP Air Navigation Service Provider

AOC Aeronautical Operational Control

ASP Actual Surveillance Performance

ATC Air Traffic Control

ATIS Automat ic Terminal Information Service

ATM Air Traffic System Management

ATN Aeronautical Telecommunication s Network

ATN B1 Aeronautical Telecommunication s Network Baseline 1

ATS Air Traffic Service

ATSU Air Traffic Service Unit

G-5

10/3/17 AC 90 -117

Appendix G

Acronym Meaning

B2 Baseline 2

CADS Centralized ADS -C System

CDA Current Data Authority

CDU Control Display Unit

CFR Code of Federal Regulations

CM Context Management

CNS Communication, Navigation, and Surveillance

CPDLC Controller -Pilot Data Link Communication

CRA Central Reporting Agency

CRD Clearance Request and Delivery

CRM Crew Resource Management

CSP Communication Service Provider

CVR Cockpit Voice Recorder

CWA Central Weather Advisory

D-ATIS Digital Automat ic Terminal Information S ervice

D-TAXI Data Link Taxi

DCL Departure Clearance

DCNS Data Communications Network Service

DLIC Data Link Initiation Capability

DLMA Data Link Monitoring Agency

DM Downlink Message

DRNP Dynamic Required Navigation Performance

DSC Downstream Clearance

DT RSP Data Delivery Time (associated with nominal continuity – 95 percent)

EPP Extended Projected Profile

ERAM En Route Automation Modernization

ET Expiration Time

EUROCAE European Organization for Civil Aviation Equipment

FAA Federal Aviation Administration

FANS Future Air Navigation System

G-6

10/3/17 AC 90 -117

Appendix G

Acronym Meaning

FBO Fixed -Base Operator

FDR Flight Data Recorder

FIR Flight Information Region

FMS Flight Management System

GA General Aviation

GOLD Global Operational Data Link (GOLD) Manual (Doc 10037)

GPS Global Positioning System

HF High Frequency (radio)

HFDL High Frequency Data Link

HMI Human -Machine Inter face

ICAO International Civil Aviation Organization

IER Information Exchange and Reporting

IFO International Field Office

IM Interval Management

INTEROP Interoperability Requirements Standards

ISPA CG Informal South Pacific Air Traffic Services Coordinating Group

ITP In-Trail Procedures

LOA Letter of Authorization

MEL Minimum Equipment List

MET I Meteorological Information

MMEL Master Minimum Equipment List

M/M/S Make, Model, and Series

MOPS Minimum Operational Performance Standard

MSpec Management Specification

MTBO Mean Time Between Outages

MU Management Unit

NAT North Atlantic

NDA Next Data Authority

NM Nautical Mile

NSDA National Single Data Authority

G-7

10/3/17 AC 90 -117

Appendix G

Acronym Meaning

OCD Oceanic Clearance Delivery

OCL Oceanic Clearance

OEM Original Equipment Manufacturer

OPR Operational Problem Report

OpSpec Operation s Specification

OT RSP data overdue time (associated with operational continuity)

PANS Procedures for Air Navigation Service

Part 91K Part 91 Subpart K

PBCS Performance -Based Communication and Surveillance

PBN Performance -Based Navigation

PDC Pre-Departure Clearance

PI Principal Inspector

PIREP Pilot Weather Report

POI Principal Operations Inspector

PORT Pilot Operational Response Time

PR Position Reporting

RA Radar Associate

RCP Required Communication Performance

RCP A AIR RCP Availability – Aircraft

RCP A CSP RCP Availability – CSP

RCP C RCP Continuity

RCP I RCP Integrity

RCTP Required Communication Technical Performance

RF Radio Frequency

RLatSM Reduced Lateral Separation Minima

RMA Regional Monitoring Agency

RNAV Area Navigation

RNP Required Navigation Performance

RSMP Required Surveillance Monitored Performance

RSP Required Surveillance Performance

G-8

10/3/17 AC 90 -117

Appendix G

Acronym Meaning

RSP A AIR RSP Availability – Aircraft

RSP A CSP RSP Availability – CSP

RSP C RSP Continuity

RSP I RSP Integrity

RSTP Required Surveillance Technical Performance

RTF Radio Telephone

SATCOM Satellite Communication

SBB SwiftBroadband

SBD Short Burst Data

SDP Service Delivery Point

SELCAL Selective -Calling System

SID Standard Instrument Departure

SIGMET Significant Meteorological Information

SITA Société International de Télécommunications Aeronautiques

SOC Statement of Compliance

SPR Safety and Performance Requirements

SSR Secondary Surveillance Radar

STC Supplemental Type Certificate

TC Type Certificate

TDLS Tower Data Link Services

TSO Technical Standard Order

TWIP Terminal Weather Information for Pilots

UM Uplink Message

VDL Very High Frequency Data Link

VHF Very High Frequency (radio)

G-9

Advisory Circular Feedback Form

If you find an error in this AC, have recommendations for improving it, or have suggestions for

new items/subjects to be added, you may let us know by contacting the Flight Technologies

Division (AFS-400) at 9-AWA-AFS400-COORD@faa.gov or the Flight Standards Directives

Management Officer at 9-AWA-AFS-140-Directives@faa.gov .

Subject: AC 90-117, Data Link Communications

Date: _______________

______

Please check all appropriate line items:

An error (procedural or typographical) has been noted in paragraph ____________

on page _______ .

Recommend paragraph _____________ on page __________ be changed as follows:

______________________________________________________________________

______________________________________________________________________

In a future change to this AC, please cover the following subject:

(Briefly describe what you want added.)

______________________________________________________________________

______________________________________________________________________

Other comments:

______________________________________________________________________

______________________________________________________________________

I would like to discuss the above. Please contact me.

Submitted by: Date: ______________________