AC 90-100A - US Terminal and En Route RNAV Operations

Advisory

Circular

Subject: U.S. Terminal and En Route

Area Navigation (RNAV) Operations Date: 03/01/07

Initiated by: AFS-400 AC No: 90-100A

1. PURPOSE.

a. This advisory circular (AC) provides operational and airworthiness guidance for

operation on U.S. Area Navigation (RNAV) routes, Instrument Depa rture Procedures (DPs), and

Standard Terminal Arrivals (STARs). Operators and pilots should use the guidance in this AC to

determine their eligibility for these U.S. RNAV rout es and procedures. In lieu of following this

guidance without deviation, operators may elect to follow an alternative method, provided the

alternative method is found to be acceptable by the Federal Aviation Administration (FAA). For

the purpose of this AC, “compliance” means meeting operational and f unctional performance

criteria. Mandatory terms in this AC such as “must” are used only to ensure applicability of

these particular methods of compliance when the acceptable means of compliance described are

used. This AC does not change, add, or delete regulatory requirements or authorize deviations

from regulatory requirements.

NOTE: New applicants for a type certificate (TC) or supplemental type certificate (STC)

should include a statement of compliance to this AC and qualification for U.S. RNAV routes

and terminal procedures when the aircra ft is found in compliance with this AC.

b. Applicability of AC 90-100A. AC 90-100A applies to operation on U.S. Area

Navigation (RNAV) routes (Q-rout es and T-routes), Departure Procedures (Obstacle Departure

Procedures and Standard Instrume nt Departures), and Standard Terminal Arrivals (STARs). It

does not apply to over water RNAV routes (ref 14 CFR 91.511, including the Q-routes in the

Gulf of Mexico and the Atlantic routes) or Alaska VOR/DME RNAV routes ("JxxxR"). It does

not apply to off-route RNAV opera tions, Alaska GPS routes or Ca ribbean routes, or helicopter

operations involving offshore or specific heliport procedures.

c. Performance-based navigation concept. This AC sets out a series of performance and

functional criteria necessary to conduct RNAV procedures. Aircraft compliant with AC 90-45A,

Approval of Area Navigation Systems for Use in the U.S. National Airspace System, may not be compliant with criteria contained herein.

d. Background. This criterion is consistent with the ICAO guidance material for the

implementation of area navigation (RNAV 1 a nd RNAV 2) operations. AC 90-100 became

effective 7 January 2005. Since then, ICAO has continued to harmonize area navigation

AC 90-100A 03/01/07

(RNAV) performance criteria. AC 90-100A refl ects these harmonized ICAO performance-based

navigation criteria as well as lessons learned from the in itial US RNAV implementation.

e. Structure. After the initial paragrap hs which include Terminology and References, this

AC is structured as follows:

o General Information (paragraph 6)

o RNAV System Eligibility (paragraph 7)

o RNAV System Approval Process (paragraph 8)

o Operator Approval Process (paragraph 9)

o Flight Crew Operating Procedures (paragraph 10)

o Pilot Knowledge Requirements and Training (paragraph 11)

o Criteria for RNAV Systems Using DME (Appendix 1)

o Criteria for RNAV Systems Using DME and Inertial (Appendix 2)

o Criteria for RNAV System F unctionality (Appendix 3)

2. CANCELLATION. Advisory Circular 90-100, U.S. Terminal and En Route Area

Navigation (RNAV) Operations, dated January 7, 2005, is canceled.

3. RELATED CODE OF FEDERAL REGULATIONS SECTIONS.

Title 14 of the Code of Federal Regulations ( 14 CFR), Part 91, sections 91.123 and 91.205; Part 95;

Part 121, section 121.349; Part 125, section 125.203; Part 129, secti on 129.17; and Part 135, section

4. TERMINOLOGY.

For the purpose of operations on RNAV routes and procedures, the following definitions are

provided:

a. Aircraft-Based Augmentation System (ABAS). A system augmenting and/or integrating

information obtained from other GNSS elements with information on board th e aircraft. The most

common form of ABAS is receiver aut onomous integrity monitoring (RAIM).

b. Area Navigation (RNAV). A method of navigation whic h permits aircraft operation on

any desired flight path within the coverage of station-referenced naviga tion aids or within the

limits of the capability of self-contained aids, or a combination of these. For the purposes of this

AC, the specified RNAV accuracy must be met 95% of the flight time.

(1) RNAV 1 requires a total system error of not more than 1 NM for 95% of the

total flight time.

(2) RNAV 2 requires a total system error of not more than 2 NM for 95% of the

total flight time.

c. Area Navigation (RNAV) System. This AC only addresses RNAV systems using

positioning inputs from GPS/GN SS and DME, and IRU. Criteria for RNAV systems are

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03/01/07 AC 90-100A

discussed in appendix 1 and 2. Criteria for RNAV system functionality is discussed in appendix

d. Critical DME. A DME facility that, when unavailable, results in navigation service

which is insufficient for DME/DME/IRU s upported operations along a specific route or

procedure. The required performance assumes an aircraft’s RNAV system meets the minimum

standard (baseline) for DME/DME RNAV sy stems found in appendix 1, or the minimum

standard for DME/DME/IRU systems found in a ppendix 2. For example, terminal RNAV DPs

and STARs may be published with only two DM Es, in which case, both are critical.

e. DME/DME (D/D) RNAV refers to navigation using DME ranging from at least two

DME facilities to determine position.

f. DME/DME/Inertial (D/D/I) RNAV refers to navigation us ing DME ranging from at

least two DME facilities to dete rmine position along with use of an inertial reference unit (IRU)

to provide sufficient position info rmation during limited DME gaps.

g. Flight Technical Error (FTE). Accuracy with which an aircraft is controlled, as

measured by the indicated aircraft position with respect to the indica ted command or desired

position. It does not include procedural blunder errors.

h. Global Navigation Satel lite System (GNSS). The GNSS is a worldwide position and

time determination system, which includes one or more satellite constellations, aircraft receivers,

and system integrity monitoring. GNSS is a ugmented as necessary to support the required

navigation performance for the actual phase of operation.

i. Global Positioning System (GPS). The U.S. GNSS core satellite constellation

providing space-based positioning, velocity, and time. GPS is composed of space, control, and

user elements.

j. Position estimation error (PEE). Difference between true position and estimated

position.

k. Receiver Autonomous Integrity Monitoring (RAIM). A technique used within a GPS

receiver/processor to monitor GPS signal performan ce. This integrity determination is achieved

by a consistency check among redundant measurements.

l. RNAV Procedure. An RNAV Instrument Departure Procedure or RNAV Standard

Terminal Arrival.

(1) Instrument Departure Procedure. A DP is a published IFR procedure

providing obstruction clearance from the terminal area to the en route stru cture. There are two

types of DPs: Standard Instrument Departur es (SIDs) and Obstacle Departure Procedures

(ODPs).

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(i) Standard Instrument Departure (SID). A SID is a published IFR air

traffic control (ATC) departure pr ocedure providing obsta cle clearance and a transition from the

terminal area to the en route structure. SI Ds are primarily designed for air traffic system

enhancement to expedite traffic flow a nd to reduce pilot/controller workload.

(ii) Obstacle Departure Procedure (ODP). A preplanned instrument flight

rule (IFR) departure procedure printed for pilo t use in textual or graphic form to provide

obstruction clearance via the least onerous route fr om the terminal area to the appropriate en

route structure. ODPs are recommended for obs truction clearance and may be flown without

ATC clearance unless an alternate departure pr ocedure (SID or rada r vector) has been

specifically assigned by ATC.

(2) Standard Terminal Arrival (STAR). A STAR is a published IFR air traffic

control arrival procedure that pr ovides a transition from the en route structure to the terminal

area. STARs may include one or more runway transitions providing guidance to either a

standard instrument approach procedure or a point in space from which radar vectors are

provided by ATC.

m. RNAV Route. An RNAV route (“Q” or “T”), within the high or low al titude structure of

the Contiguous United States, requiring syst em performance by GPS/GNSS or DME/DME/IRU

RNAV systems, as required.

n. Total System Error. The difference between the true pos ition and the desired position.

This error is equal to the vector sum of the path steering error, path definition error, and position

estimation error.

5. REFERENCES.

(NOTE: All references to the edition are cu rrent as of the public ation date of this AC).

a. Technical Standard Order (TSO) C66c, Distance Measuring Equipment (DME)

Operating within the Radio Fre quency Range of 960-1215 Megahertz.

b. TSO-C115b, Airborne Area Navigation Equipm ent Using Multi-Sensor Inputs.

c. TSO-C129a, Airborne Supplemental Naviga tion Equipment Using the Global

Positioning System (GPS).

d. TSO-C145a, Airborne Navigation Sensors Using the Global Positioning System (GPS)

Augmented by the Wide Area Augmentation System (WAAS).

e. TSO-C146a, Stand-Alone Airborne Navigation Equipment Usi ng the Global Positioning

System (GPS) Augmented by the Wide Area Augmentation System (WAAS).

f. Advisory Circular (AC) 20-130A, Airworthiness Approval of Navigation or Flight

Management Systems Integrating Multiple Navigation Sensors.

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03/01/07 AC 90-100A

g. AC 20-138A, Airworthiness Approval of Global Navigation Satellite System (GNSS)

Equipment.

h. AC 20-153 , Acceptance of Data Processes a nd Associated Navigation Databases

i. AC 25-4, Inertial Navigation Systems (INS).

j. AC 25-15 , Approval of Flight Management Systems in Transport Category Airplanes.

k. AC 90-45A, Approval of Area Navigation Systems fo r Use in the U.S. National Airspace

System.

l. AC 90-94, Guidelines for Using Global Positioni ng System Equipment for IFR En Route

and Terminal Operations and for Non-Precision Instrument Approaches in the U.S. National

Airspace System.

m. AC 90-96A, Approval of U.S. Operators and Aircraft to Operate Under Instrument Flight

Rules (IFR) in European Airspace Designate d for Basic Area Navi gation (B-RNAV) and

Precision Area Navigation (P-RNAV).

n. FAA Order 7470.1A, Distance Measuring Equipment (DME)/DME Infrastructure

Evaluations for Area Navigation (RNAV) Routes and Procedures.

o. JAA TGL-10, Airworthiness and Operational Appr oval for Precision RNAV Operations

in Designated European Airspace and the corresponding JAA TGL-10 Frequently Asked

Question s (FAQ) Document.

p. RTCA/DO-187, Minimum Operational Performance Standards for Airborne Area

Navigation Equipment Usi ng Multi-Sensor Inputs.

q. RTCA/DO-189, Minimum Performance Standard fo r Airborne Distance Measuring

Equipment (DME) Operating Within the Ra dio Frequency Range of 960-1215 Megahertz.

r. RTCA/DO-200A, Standards for Processing Aeronautical Data.

s. RTCA/DO-201A, Standards for Aeronautical Information.

t. RTCA/DO-236B, Minimum Aviation System Perf ormance Standard: Required

Navigation Performance for Area Navigation.

u. RTCA/DO-283A , Minimum Operational Perfor mance Standards for Required

Navigation Performance for Area Navigation.

6. GENERAL INFORMATION ON RNA V 1 AND RNAV 2 OPERATIONS.

a. Operation on U.S. RNAV routes, DPs, and STARs :

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AC 90-100A 03/01/07

(1) Relies on normal descent profiles and identifies minimum segment altitude

requirements;

NOTE: Pilots operating aircraft with an approved Baro-VNAV system may

continue to use their Baro-VNAV system while executing U.S. RNAV routes, DPs,

and STARs. Operators must ensure compli ance with all altitude constraints as

published in the procedure by reference to the barometric altimeter.

(2) Does not require the pilot to monitor ground-based NAVAIDs used in position

updating unless required by the Airplane Flight Manual (AFM ), Pilot Operating Handbook

(POH), or the operating ma nual for their avionics;

(3) Bases obstacle clearance assessments on the associated required system

performance; and

(4) Guidance in this AC does not supersede appropriate operating requirements for

equipage. For example, Part 91 can have a sing le RNAV system, and Part 121 can have a single

RNAV system and another independent navigati on system allowing safe flight to a suitable

alternate airport.

b. The DME navigation infrastructure supporting the design of an RNAV route or

procedure has been assessed and validated by the FAA. This includes analysis by FAA flight

inspection assets. DME coverage may use Expanded Service Volume (ESV) for select DME

facilities so there is no requi rement to use VOR, LOC, NDB, or AHRS during normal operation

of the DME/DME RNAV system. ESV facilities re quire a satisfactory flight inspection prior to

use.

(1) DME signals are considered to meet signal-in-space accuracy tolerances everywhere

the signals are received.

(2) For RNAV operations where reliance is place d upon the IRU, some aircraft systems

temporarily revert to VOR/DME-b ased navigation before reverti ng to inertial coasting. When

the VOR is within 40 NM from the route/pr ocedure and there is insufficient DME/DME

navigation infrastructure, the impact of VOR ra dial accuracy has been evaluated by the FAA and

determined to not affect aircraft position accuracy.

(3) The available navigation infrastructure supporting the procedure will be clearly

designated on all appropriate charts (for example, GPS or DME/DME/IRU).

(4) The FAA will monitor the navigation infrastructure and issue timely warnings of

outages (NOTAM).

(5) The navigation standard (for example, RNAV 1 or RNAV 2) required for all RNAV

procedures/routes will be clearly designated on all appropriate charts. However, SIDs, ODPs,

and STARs will be flown with RNAV 1 procedures.

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(6) All routes and procedures referenced in this AC are intended to be flown by

DME/DME/IRU and/or G PS/GNSS equipped aircraft meeting the performance requirements in

this AC.

c. If any critical DME facilities exist , they are identified within the relevant U.S. Flight

Information Publications (FLIP).

d. Unless the RNAV route, DP, or STAR specifically requires GPS or GNSS equipage,

aircraft on the RNAV route, DP, or STAR mu st be within ATC radar surveillance and

communication.

e. All DME ground stations maintained by the FAA and used to define the availability of

these RNAV routes, DPs, and STARs comply with applicable ICAO standards.

f. All routes/procedures must be based upon WGS 84 coordinates.

g. The navigation data published for the routes, procedures and supporting navigation aids

must meet the requirements of ICAO Annex 15.

7. RNAV SYSTEM ELIGIBILITY

a. Aircraft with a statemen t of compliance to this AC in their Aircraft Flight Manual

(AFM), Pilot Operating Handbook (POH), or the operating manual for their avionics meet the

performance and functional requirements of this AC.

b. Aircraft with P-RNAV approval based on GNSS capability meet the functional

requirements of this AC. Due to differences in ra dio navigation infrastructure in the United States,

if the approval is based on DME/DME or DME/DME/IRU, the operator should ensure the

equipment meets the criteria in appendix 1 or 2, as applicable.

c. The following systems meet many of the requirements defined in this AC. Such

equipment still requires evaluation by the manufacturer against all the functional and

performance requirements in this AC. The RA IM prediction program should comply with the

criteria in AC 20-138A, paragraph 12.

(1) Aircraft with TSO-C129/C129a sensor (Class B or C) and the requirements in a

TSO-C115b FMS, installed for IFR use IAW AC 20-130A.

(2) Aircraft with TSO-C145a sensor , and the requirements in a TSO-C115b FMS,

installed for IFR use IAW AC 20-130A or AC 20-138A.

(3) Aircraft with TSO-C129/C129a Class A1 (without deviating fr om the functionality

described in Appendix 3 of this document) installed for IFR use IAW AC 20-138 or AC 20-

138A.

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AC 90-100A 03/01/07

(4) Aircraft with TSO-C146a (without deviating from the f unctionality described in

Appendix 3 of this document) inst alled for IFR use IAW AC 20-138A.

NOTE: Refer to paragraph 5 for TSO and AC references.

d. Aircraft with a statement from the manufacturer documenting compliance with the

criteria in this AC (appendix 1 or 2, as applicable, and appendix 3) meet the performance and

functional requirements of this AC. These statem ents should include the airworthiness basis for

compliance. Compliance with the sensor requiremen ts in paragraph 8 will have to be determined

by the equipment or aircraft manufacturer, while compliance with the functional requirements in

Appendix 3 may be determined by the manuf acturer or by inspection by the operator.

NOTE 1: Aircraft with a demonstrated RNP capab ility will annunciate when no longer

satisfying the performance requirement asso ciated with the operation. However, for

DME/DME/IRU-based procedures, the manufac turer still has to determine compliance

with appendix 1 or 2 to support evalu ation of the DME infrastructure.

NOTE 2: Aircraft with a TSO-C129 GPS sensor and a TSO-C115 or C115a FMS may not

meet all of the requirements defined in this AC. Such equipment would require further

evaluation by the manufacturer against all the functional and perf ormance requirements

in this AC.

8. RNAV SYSTEM APPROVAL PROCESS

a. Navigation System Accuracy. The navigation system accuracy is dependent on the total

system error, defined in paragraph 4 of this AC.

(1) RNAV Routes: Aircraft operating on RNAV rout es must maintain a total system

error bounded by the RNAV value for 95% of the tota l flight time. A flight technical error (FTE)

of 1.0 NM (95%) is acce ptable for RNAV 2 operations. RNAV 2 will be used for en route unless

otherwise specified.

(2) RNAV 1 DPs and STARs. Aircraft operating on RNAV 1 DPs and STARs must

maintain a total system error of not more than 1 NM fo r 95% of the total fli ght time. An FTE of

0.5 NM (95%) is acceptable for RNAV 1 operations. RNAV 1 will appear on all RNAV SID and

STAR charts.

b. Navigation Sensors. U.S. RNAV operations are based upon the use of RNAV

equipment that automatically determines aircra ft position in the horizon tal plane using inputs

from the following types of positioning sensors (no specific priority).

(1) Global Navigation Satellite System (GNSS) in accordance with TSO-C145a, TSO-

C146a, and TSO-C129/C129a. Positioning data from other types of navigation sensors may be

integrated with the GNSS data provided it doe s not cause position errors exceeding the total

system error requirements. Th e use of GPS equipment approved to TSO-C129() is limited to

those which include the minimum system functions specified in Appendix 3. As a minimum,

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03/01/07 AC 90-100A

integrity should be provided by ABAS. In addition, GPS stand-alone equipment should include

the following additional functions:

o Pseudorange step detection

o Health word checking.

For procedures requiring GPS and/ or aircraft approvals requiring GPS, if the navigation system

does not automatically alert the flight crew of a loss of GPS, the ope rator must develop

procedures to verify correct GPS operation.

(2) DME/DME RNAV equipment complying with the criter ia in appendix 1. Based

on current DME availability evaluations, covera ge is not sufficient to support DME/DME

RNAV operations without additional IRU augmentation or using GPS.

(3) DME/DME/IRU RNAV equipment complying with the criteria in appendix 2.

NOTE: LORAN-C criteria have not been developed.

c. Functional criteria listed in Appendix 3. The requirements of Appendix 3 help

ensure aircraft RNAV system perfor mance meets procedure design criteria.

9. OPERATOR APPROVAL PROCESS

a. Background. This section identifies the operati onal requirements for RNAV 2 and

RNAV 1 operations. Performan ce requirements must be met. However, the approval process

depends on the operating rules for the particular operation (e.g., part 91 versus part 121).

b. After completing the following steps, an RNAV operational a pproval or appropriate

operations specifications/management specificati ons (OpsSpecs/Mspecs), should then be issued

by the FAA before conducting RNAV operations. Part 91 operators (excluding subpart K)

meeting the RNAV performance requirements in th is AC should follow the aircraft and training

guidance in this AC, but are not require d to obtain a Letter of Authorization.

(1) Aircraft equipment eligibility must be determined and documented;

(2) Operating procedures for the navigation systems to be used and the operator

navigation database process must be documented;

(3) Flight crew training based upon the operat ing procedures must be documented;

(4) The above material must be accepted by the FAA; and operational approval should

then be obtained in accord ance with operating rules.

c. Documentation for Conducting RNAV Operations

(1) Aircraft Eligibility

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AC 90-100A 03/01/07

(a) Description of aircraft equipment. Th e operator must have a configuration list

detailing pertinent components and equi pment to be used for RNAV 2/RNAV 1.

(b) Eligibility airworthiness documents. Relevant documentation acceptable to

the FAA must be available to establish that th e aircraft is equipped with RNAV systems meeting

RNAV 2/RNAV 1 requirements. Manufacturers evalua te their systems against these criteria, and

a current list of compliant equipment can be found at the AFS-410 websit e (applicable to all

operators):

http://www.faa.gov/about/office_org/headquarters_offices/avs/offices/afs/afs400/afs410/poli

cy_guidance/

Pilots and operators can confirm the capability of their equipment on this list, or obtain

equipment performance information from the re levant aircraft and avionics manufacturer.

(2) Training documentation

(a) Part 91K, 121, 125, 129 and 135 operators should have a training program

addressing the operational practices , procedures and training items identified in paragraph 11 of

this AC (e.g., initial, upgrade or recurrent trai ning for flight crew, disp atchers or maintenance

personnel).

NOTE: It is not required to establish a separate training program or regimen if RNAV

training in paragraph 11 is already an inte grated element of a training program.

(b) Part 91 operators should be familiar with the practices and procedures

identified in paragraph 11, Pilot Knowledge Requirements and Training.

(3) Operations manuals and checklists

(a) Operations manuals and checklists for commercial operators must address

information/guidance on the standa rd operating procedures detailed in paragraph 10 of this AC.

The appropriate manuals should contain naviga tion operating instructions and contingency

procedures where specified. Manuals and checklists must be submitted for review as part of the

application process.

(b) Private operators should operate using the practices and procedures identified

in paragraph 11, Pilot Knowledge Requirements and Training.

(4) Maintenance considerations

(a) Any minimum equipment list (MEL) re visions necessary to address RNAV

provisions must be approved.

(b) If an RNAV operational approval is granted on the basis of a specific

operational procedure, operators must modify the MEL, or equivalent, and specify the required dispatch conditions.

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NOTE: Since this may constitute a special operation, it is not intended to require MEL

requirements for each aspect of RNAV operations.

(c) Part 91K, 121, 125, 129 and 135 operators should have an approved

maintenance program.

10. U.S. RNAV FLIGHT CREW OPERATING PROCEDURES.

Pilots should be familiar with the normal operating and contingency procedures associated with

U.S. RNAV routes, DPs, and STARs.

a. Pre-flight Planning.

(1) Operators and pilots intending to conduct operations on U.S. RNAV routes, DPs,

and STARs are expected to file the appropriate flight plan su ffix code as designated in the

current Aeronautical Informati on Manual (AIM) and other FLIP.

(2) NOTAMs should be checked to ve rify the health of critical DMEs for navigation

relying on DME. Pilots should a ssess their capability to navigate (potentially to an alternate

destination) in case of failure of critical DME while airborne.

(3) The onboard navigation data must be current and appropriate for the region of

intended operation and must include the navigati on aids, waypoints, and relevant coded terminal

airspace procedures for the depart ure, arrival, and alternate airfields. RNAV STAR procedures

may be designed using multiple runway transitions. Operators not having this functionality shall

provide an acceptable alternative means (for exam ple, a tailored navigation data base). If no

equivalent means are available to fly the char ted RNAV procedure containing multiple runway

transitions, operators will not file or accept clearance for these procedures.

NOTE: Navigation databases are expected to be current for the duration of the flight. If

the AIRAC cycle will change during flight , operators and pilots should establish

procedures to ensure the accuracy of navi gation data, including suit ability of navigation

facilities used to define the routes and proce dures for flight. Traditionally, this has been

accomplished by verifying electronic data agai nst paper products. One acceptable means

is to compare aeronautical charts (new and old) to verify navigation fixes prior to dispatch.

If an amended chart affecting navigation data is published for the procedure, the database

must not be used to conduct the procedure.

(4) If not equipped with GPS/GNSS, aircraft must be capable of navigation system updating using DME/DME/IRU for RNAV 2 or RN AV 1 routes, as well as RNAV 1 Departure

Procedures (DPs) and Standard Terminal Arrivals (STARs). As stated in paragraph 8.b.(1), if

the navigation system does not automatically aler t the flight crew of a loss of GPS/GNSS, the

operator must develop procedures to verify correct GPS/GNSS operation.

(5) If TSO-C129 equipment is used to solely satisfy the RNAV requirement, GPS

RAIM availability must be confirmed for the intended route of flight (route and time) using

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current GPS satellite information. The availabili ty of SBAS or ABAS fault detection can be

determined through NOTAMs (if available) or through prediction for the intended RNAV 1 or

RNAV 2 operation. Operators may choose to monitor the status of each satelli te in its plane/slot

position, account for the latest G PS constellation NOTAMs, and compute RAIM availability

using model-specific RAIM prediction software , or by using the FAA en route and terminal

RAIM prediction website: www.raimprediction.net , or by contacting a Flight Service Station.

Receiver RAIM prediction capability can also be used. In the event of a predicted, continuous

loss of RAIM of more than five (5) minutes for a ny part of the intended flight, the flight should

be delayed, canceled, or re-routed where RAIM requirements can be met. Pilots should assess

their capability to navigate (potentially to an alternate destination) in case of failure of GPS

navigation.

(6) If TSO-C145/C146 equipment is used to satisfy the RNAV requirement, the pilot/

operator need not perform the pr ediction if WAAS coverage is confirmed to be available along

the entire route of flight.

NOTE: Outside the U.S. or in areas where WAAS coverage is not available, operators

using TSO-C145/C146 receivers are requi red to check GPS RAIM availability.

(7) Proper interpretation of Pre-Departure Clearance (PDC) and printed routings.

Pilots of operators using PDC a nd printed routings must be able to properly interpret their

assigned clearance. Specifically, pilots must be able to recognize di rect routings, assigned

altitudes, revised clearances, SI Ds, and en route transitions. Pilots must understand their

operator’s PDC notation and must request clarifica tion from ATC if any doubt exists with regard

to their clearance.

b. General Operating Procedures. Operators and pilots shoul d not request or file U.S.

RNAV routes or procedures unless satisfying the criteria in this AC. If an aircraft not meeting these criteria receives a clea rance from ATC to conduct an RNAV procedure, the pilot must

advise ATC that he/she is una ble to accept the clearance and request alternate instructions.

(1) The pilot should comply with any instructions or procedures identified by the

manufacturer as necessary to comply with the equipment requirements of this AC.

( 2 ) At system initialization, pilots must confirm the navigation database is current and

verify the aircraft’s present position.

( 3 ) RNAV DPs and STAR procedures must be retrieved by procedure name from

the onboard navigation database and c onform to the charted procedure.

(4) Whenever possible, RNAV routes should be extracted from the database in their

entirety, rather than loading RNAV route waypoints from the da tabase into the flight plan

individually. Selecting and inse rting individual, named fixes from the database is permitted,

provided all fixes along the published route to be flown are inserted.

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NOTE: This does not preclude the use of panel-mount GPS/GNSS avionics to meet

the requirements of this AC to fly RNAV routes.

(5) Manual entry of waypoints using lati tude/longitude or place/bearing is not

permitted. Additionally, pilots must not change a ny RNAV DP or STAR database waypoint

type from a fly-by to a fly-over or vice versa.

(6) Flight crews should crosscheck the cleared flight plan against charts or other

applicable resources, as well as the navigation system textual display and the aircraft map

display, if applicable. If requi red, confirm exclusion of a specific navigation aid. A procedure

should not be used if doubt exists as to the valid ity of the procedure in the navigation database.

NOTE: Pilots may notice a slight difference between the navigation information

portrayed on the chart and their primary navigation display. Differences of 3 ° or less

may result from equipment manufacturer's application of magnetic variation and are

operationally acceptable.

(7) Verification of assigned route a nd correct entry of transitions into RNAV

System/Flight Management System (FMS).

(a) DPs. Prior to flight, pilots must verify their aircraft navigation system is

operating correctly and the correct runway and departure procedure ( including any applicable en

route transition) are entered and properly depicted. Pilots who are assigned an RNAV departure

procedure and subsequently receive a change of runwa y, procedure or transition must verify the

appropriate changes are entered and available for navigation prior to takeoff. A final check of

proper runway entry and correct route depicti on, shortly before takeoff, is recommended.

(b) Routes. Pilots must verify proper en try of their ATC assi gned route upon initial

clearance and any subsequent change of route. P ilots must ensure the waypoints sequence

depicted by their navigation system matches the route depicted on the ap propriate chart(s) and

their assigned route.

(c) STARs. Pilots must verify their airc raft navigation system is operating correctly

and the correct arrival procedure and runway (including any applicable transition) are entered

and properly depicted.

(8) Use of navigation map displays. Prior to takeoff, pilots of aircraft with a

navigation map display should veri fy the relationship of the ai rcraft position symbol to their

assigned runway (if available) a nd route on their display matches ex ternal visual cues, as well as

charts. Specifically, once on or ne ar their assigned runway, pilots should ensure their navigation

display reflects the same relative position to the runway and the route depiction reflects that of

the respective chart. During flight , these displays should be used in concert with textual displays

for route verification.

(9) Pilots must use a lateral deviatio n indicator (or equivalent navigation map

display), flight director and/or auto pilot in lateral navigation m ode on RNAV 1 routes. Pilots

Par 10b(4) Page 13

AC 90-100A 03/01/07

are encouraged to use a lateral deviation indicator (or equivalent navigation map display), flight

director and/or autopilot in late ral navigation mode on RNAV 2 routes . Pilots of aircraft with a

lateral deviation indicator (e.g., a standalone GNSS receiver) must ensure that lateral deviation

indicator scaling (full-scale deflection) is suitabl e for the navigation accuracy associated with the

route/procedure (i.e., ±1 nm for RNAV 1, ± 2.0 nm for RNAV 2).

NOTE: Some TSO-C129() equipment automa tically goes to ±5.0 NM beyond 30 NM

from the airport reference point. This is acceptable provided the pilot maintains the

required minimum performance standard associated with the procedure.

All pilots are expected to maintain route centerlines, as depicted by onboard lateral deviation

indicators and/or flight gui dance during all RNAV operations described in this AC unless

authorized to deviate by ATC or under emergency conditions. For normal operations, cross-

track error/deviation (the difference between the RNAV system computed path and the aircraft

position relative to the path) should be limited to ± ½ the navigation accuracy associated with the

procedure or route (i.e., 0.5 nm for RNAV 1, 1.0 nm for RNAV 2). Brief deviations from this

standard (e.g., overshoots or unde rshoots) during and immediately af ter procedure/ro ute turns, up

to a maximum of 1 times the navigation accuracy (i.e., 1.0 nm for RNAV 1, 2.0 nm for RNAV 2), are allowable.

NOTE: Some aircraft do not display or compute a path during turns. As such,

pilots of these aircraft may not be able to adhere to the ± ½ lateral navigation accuracy during procedural/rou te turns but are still expec ted to satisfy the standard

during intercepts following turn s and on straight segments.

(10) If ATC issues a heading assignment taking the aircraft off a procedure, the pilot

should not modify the route in the RNAV system until a clearan ce is received to rejoin the

procedure or the controller confirms a new route clearance. When the aircraft is not on the

published procedure, the specifi ed accuracy requirement (par agraph 8.a.) does not apply.

(11) Manually selecting aircraft bank limiting functions may reduce the aircraft’s

ability to maintain its desired track and are not reco mmended. Pilots should recognize manually

selectable aircraft bank-limiting functions mi ght reduce their ability to satisfy ATC path

expectations, especially when ex ecuting large angle turns. This should not be construed as a

requirement to deviate from Airp lane Flight Manual procedures ; rather, pilots should be

encouraged to limit the selection of such functions within accepted procedures.

(12) DPs and STARs are flown as RNAV 1 procedures. RNAV routes are flown as

RNAV 2 unless otherwise specified.

(13) Pilots operating RNP-approved aircraft under the provisions of this AC are not required to modify manufacturer's RNP default values established in the Flight Management

Computers.

c. RNAV DP and STAR Specific Requirements.

Page 14 Par 10b(9)

03/01/07 AC 90-100A

(1) RNAV DP Engagement Altitudes. For DPs, the pilot mu st be able to engage

RNAV equipment to follow flight guidance for lateral RNAV no later than 500 feet above

airport elevation.

(2) Pilots must use a lateral deviatio n indicator (or equivalent navigation map

display), flight director and/or auto pilot in lateral navigation m ode on RNAV 1 routes. The full-

scale CDI deflection value of ±1 NM is acceptable.

(3) DME/DME/IRU (D/D/I) Aircraft . Pilots of aircraft without GPS/GNSS, using

DME/DME/IRU, must ensure the aircraft navigation system position is confirmed, within

1,000 feet, at the start point of ta ke-off roll. The use of an automatic or manual runway update is

an acceptable means of compliance with this requirement. A navigation map may also be used

to confirm aircraft position, if pilot procedures and display resolution a llow for compliance with

the 1,000-foot tolerance requirement.

(4) GNSS Aircraft. When using GNSS, the signal must be acquired before the take-off

roll commences.

NOTE: For aircraft using TSO-C129/C129a, the departure airport must be loaded into the

flight plan in order to achieve the appr opriate navigation system monitoring and

sensitivity. For aircraft us ing TSO-C145a/C146a avionics, if the departure begins at a

runway waypoint, then the departure airport does not need to be in th e flight plan to obtain

appropriate monitoring and sensitivity.

d. Contingency Procedures. The pilot must notify ATC of any loss of the RNAV

capability, together with the proposed course of action. If unable to comply with the

requirements of an RNAV procedure, pilots must advise Air Traffic Contro l as soon as possible.

For example, ". . .N1234, failure of GPS/ GNSS system, unable R NAV, request amended

clearance." The loss of RNAV cap ability includes any failure or event causing the aircraft to no

longer satisfy the criteria of this AC. Example failures incl ude, but are not limited to, loss of

autopilot/flight director (if required), or reversion to na vigation other than GNSS or

DME/DME/IRU (even though no pilot monitoring of navigation updating source is required). In the event of communications failure, establishe d lost communication pr ocedures should be

followed.

11. PILOT KNOWLEDGE REQU IREMENTS AND TRAINING.

The pilot is expected to be knowledgeable in the following areas. Also, for Parts 121, 125, 129,

135, and 91 Subpart K operators, the approved tr aining program should address the elements

listed below. This training program should provide sufficient training (for example, simulator,

training device, or aircraft) on th e aircraft’s RNAV system to the extent that the pilots are not

just task oriented. Training need not be repe ated if it addresses specific items listed below.

a. The information in this AC.

b. The meaning and proper use of Aircraft Equipment/Navigation Suffixes .

Par 10b(4) Page 15

AC 90-100A 03/01/07

c. Procedure characteristics as determ ined from chart depiction and textual

description.

(1) Depiction of waypoint types (fly-over and fly-by) and pa th terminators (provided in

Appendix 3 and any other types used by the operator) as well as associated aircraft flight paths.

(2) Required navigation equipment for operation on RNAV routes, DPs, and STARs

(for example, DME/DME/IRU and GPS/GNSS).

(3) Phraseology. Some RNAV procedures may incorporate the use of “Descend via”

clearances. Pilots should be familiar with the correct use of the terminology and procedures as

mentioned in AIM (refer to Air Traffic Procedures, Arrival Procedures).

d. RNAV system-specific information:

(1) Levels of automation, mode annunciations , changes, alerts, interactions,

reversions, and degradation.

(2) Functional integration with other aircraft systems.

(3) The meaning and appropriat eness of route discontinuities as well as related

flight crew procedures.

(4) Monitoring procedures for each phase of flight (for example, monitor PROG or

LEGS page).

(5) Types of navigation sensors ( for example, DME, IRU, GPS/GNSS) utilized by the

RNAV system and associated system prioritization/weighting/logic.

(6) Turn anticipation with considerati on to speed and altitude effects.

(7) Interpretation of electronic displays and symbols.

e. RNAV equipment operating procedures , as applicable, includi ng how to perform the

following actions:

(1) Verify currency of aircraft navigation data.

(2) Verify successful comple tion of RNAV system self-tests.

(3) Initialize RNAV system position.

(4) Retrieve and fly a DP or STAR with appropriate transition.

(5) Adhere to speed and/or altitude constraints associated with a DP or STAR.

Page 16 Par 10c(2)

03/01/07 AC 90-100A

(6) Make a runway change associated with a DP or STAR.

(7) Verify waypoints and flight plan programming.

(8) Perform a manual or automatic runway update (with takeoff point shift, if

applicable).

(9) Fly direct to a waypoint.

(10) Fly a course/tra ck to a waypoint.

(11) Intercept a course/track.

(12) Be vectored off and rejoin a procedure.

(13) Determine cross-tr ack error/deviation.

(14) Insert and delete/clear route discontinuity.

(15) Remove and reselect n avigation sensor input(s).

(16) When required, confirm excl usion of a specific navigation aid or navigation aid

type.

(17) Insert and delete a lateral offset.

(18) Change the arrival airport and alternate airport.

(19) Insert and delete a holding pattern.

f. Operator-recommended levels of automation for phase of flight and workload,

including methods to minimize cross-track error to maintain procedure centerline.

g. Contingency procedures for RNAV failures.

Original Signed By

Roger Forshee

James J. Ballough

Director, Flight Standards Service

Par 11c(1) Page 17

03/01/07 AC 90-100A

Appendix 1

APPENDIX 1. CRITERIA FOR APPROVAL OF BASELINE AREA NAVIGATION

(RNAV) SYSTEMS USING DISTANCE MEASURING EQUIPMENT (DME)

1. PURPOSE.

The FAA is responsible for evaluating DME/DME coverage and availability against a minimum

standard DME/DME RNAV system for each route and procedure. Deta iled criteria defining

DME/DME RNAV system performance as it relates to the DME infrastructure is needed. This

appendix defines the minimum performance and functions (baseline) for DME/DME RNAV

systems intended to support the implementation of RNAV 1 and RNAV 2 routes, as well as

RNAV 1 Departure Procedures (DPs ) and Standard Terminal Arrivals (STARs). These criteria

may be applied under an airworth iness approval for new equipment or used by the manufacturer

for self-certification of existing equipment.

2. MINIMUM REQUIREMENTS FOR DME/DME RNAV SYSTEM.

a. Tuning and Updating Position of DME Facilities. The DME/DME RNAV system must:

(1) Position update within 30 seconds of tuning DME navigation facilities.

(2) Auto-tune multiple DME facilities.

(3) Provide continuous DME/DME position updating. (Given a third DME facility

or a second pair has been available for at least the previous 30 seconds, there must be no interruption in DME/DME positioning when the RNAV system switches between DME

stations/pairs.)

b. Using Facilities in the Airport/Facility Directory. The FAA cannot ensure all DME

signals within reception distance of U.S. airspace meet International Civil Aviation Organization

(ICAO) standards. These could include non-U.S. DME facilities, or Department of Defense

(DOD) maintained DME facilities excluded from the National Airspace System (NAS) database.

DME/DME RNAV procedure design will only use DME facilities listed in the Airport/Facility

Directory (A/FD). Although a procedure design i ssue, applicants may mitigate this restriction

by:

(1) Having the DME/DME RNAV system only use DME facilities listed in the A/FD.

(2) Requiring exclusion of non-NAS DME facilities from the aircraft’s navigation

database when the RNAV routes or procedures are within reception range of these non-NAS

DME facilities.

(3) Demonstrating to the FAA that their RNAV system performs reasonableness

checks to detect errors from the non-NAS DME faci lities and excludes these facilities from the

navigation position solution when appropriate (e.g., using the ARINC 424 coding to preclude

Page 1

AC 90-100A 03/01/07

Appendix 1

tuning co-channel DME facilities when the DME facilities signals-in-s pace overlap). See

Appendix 1, paragraph 3 for guidance on testing of reasonableness checks.

c. DME Facility Relative Angles. When needed to generate a DME/DME position, the

DME/DME RNAV system (referred to as FMS hereaf ter) must use, as a minimum, DMEs with a

relative include angle between 30 ° and 150°. The FMS may use DME pairs outside these angles

(for example, 20 ° to 160°).

d. RNAV System Use of DMEs. The RNAV system may use any receivable DME facility

(listed in the A/FD) regardless of its location. When needed to generate a DME/DME position,

as a minimum, the RNAV system must use an available and valid low altitude and/or high

altitude DME anywhere within the following regi on around the DME facility:

(1) Greater than or equal to 3 NM from the facility ; and

(2) Less than 40 degrees above the horizon when viewed from the DME facility; and

(3) For facilities with an AR INC 424 figure of merit (FOM), the RNAV system may

use the FOM value as the acceptable, usable region:

The aircraft’s DME/DME RNAV system must be : If the ARINC 424 FOM is:

Less than or equal to: And less than:

0 40 NM from the facility 12,000 ft above facility elevation

1 70 NM from the facility 18,000 ft above facility elevation

2 130 NM from the facility --

3 160 NM from the facility --

NOTE 1: RNAV systems may use additional DME fa cilities (for example, a LOC DME

facility may be used but is not required to be used for positioning). RNAV systems are not

required to use the FOM value

NOTE 2: RNAV routes and procedures may include new FOMs with Expanded Service

Volumes.

(4) A valid DME facility:

(a) Broadcasts an accurate facility identifier signal,

(b) Satisfies the minimum field strength requirements, and

(c) Is protected from oth er interfering DME signals according to the co-channel

and adjacent channel requirements.

e. No Requirement to Use VOR, NDB, LOC, IRU or AHRS. There is no requirement to

use VOR (VHF omni-range), LOC (localizer), NDB (non-directional beacon), IRU (inertial

Page 2

03/01/07 AC 90-100A

Appendix 1

reference unit) or AHRS (attitude heading reference system) during normal operation of the

DME/DME RNAV system.

f. Position estimation error. A minimum of two DME facilities satisfying the criteria in

paragraph 2, and any other valid DME facilities not meeting that criteria, the 95% position estimation error must be better than or equal to 1.75 NM. A flight tec hnical error contribution

not exceeding 1.0 NM (95%) may be assumed for RNAV 2 operations.

NOTE 1: This performance requirement is met for any navigation system that uses two

DME stations simultaneously, limits the DME inclusion angle to between 30 and 150 °

and uses DME sensors that meet the accura cy requirements of TSO- C66c. If the RNAV

system uses DME facilities outside the range identified above, the DME signal-in-space

error can be assumed to be 0.1 NM 95%.

NOTE 2: When using a minimum of two DME fa cilities satisfying the criteria in appendix 3,

paragraph 2.d., the 95% position estimation error must be better than or equal to the

following equation:

) sin()2 2( )2 2(2 2, 2 , 2 , 1 , 1

/ασ σ σ σσsis air sis air

DME DME+ + +≤

Single facility reference, where: σsis = 0.05 NM

σair is MAX {(0.085 NM, (0.125% of distance)}

α = inclusion angle (30o to 150o)

g. Preventing Erroneous Guidance from Co-Channel Facilities. The RNAV system

must ensure co-channel DME facilities do not cause erroneous guidance. This could be

accomplished by including VOR reasonableness ch ecking when initially tuning a DME facility

or excluding a DME facility when there is a co-channel DME within line-of-sight. See

appendix 3, paragraph 3 for guidance on testing of reasonableness checks.

NOTE: The DME assessment cannot use a DME facility when there is a co-channel

DME facility within line-of-sight.

h. Preventing Erroneous VOR Signals-in-Space. The RNAV system must ensure an

erroneous VOR signal-in-space does not cause the position accuracy to exceed 1.75 NM for

RNAV 2 and 0.87 NM for RNAV 1. This coul d be accomplished by not using VOR signals

when DME/DME will be available or weight ing and/or monitoring the VOR signal with

DME/DME to ensure it does not mislead position results (for example, through reasonableness checks). See paragraph 3 for guidance on testing of reasonableness checks.

i. Ensuring RNAV Systems Use Operational Facilities. The RNAV system must use

operational DME facilities. DME facilities li sted by NOTAM as unavail able (for example,

under test or other maintenance) could still reply to an airborne interrogation. (Therefore, non-operational facilities must not be used.) An RNAV system may exclude non-operational

facilities by checking the identification or inhi biting the use of facilities identified as not

operational.

Page 3

AC 90-100A 03/01/07

Appendix 1

j. Operational Mitigations. Operational mitigations defined to qualify equipment with

this AC will not require pilot action during critical phases of flight, pilot m onitoring of the

RNAV system’s navigation updating source(s), or time intensive programming/ blackballing of

multiple DME stations prior to executing a procedure.

NOTE 1: Blackballing single facilities liste d by NOTAM as out-of-service and/or

programming route/procedure-defined “critical” DME is acceptable when this

mitigation requires no pilot action during a critical phase of flight. A programming requirement also does not imply the pilo t should complete manual entry of DME

facilities not in the navigati on database. Instead, this allo ws RNAV systems to tune a

critical DME, as appropriate to a specific route or procedure.

NOTE 2: The critical phase of flight is normally from the final approach fix on an

approach procedure through missed approach, or from field elevation to 2,500 ft

above airport elevation on a departure.

3. REASONABLENESS CHECKS.

Many FMSs perform a reasonableness check to verify valid DME measurements.

Reasonableness checks are very effective against da tabase errors or erroneous system acquisition

(such as co-channel facilities), and typically fall into two classes:

• Those the FMS uses after it acquires a new DME. The FMS compares the aircraft’s

position before using the DME to the aircraft’s range to the DME, and

• Those the FMS continuously uses, based on re dundant information (for example, extra

DME signals or IRU data).

a. General Requirements. The reasonableness checks are in tended to prevent navigation

aids from being used for navigation update in areas where the data can lead to radio position

fixing errors due to co-channel in terference, multipath, and direct signal screening. In lieu of

using radio navigation aid publis hed service volume, the navi gation system should provide

checks, which preclude use of duplicate fr equency NAVAIDs within range, over-the-horizon

NAVAIDs, and use of NAVAIDs with poor geometry.

b. Assumptions. Under certain conditions, reas onableness checks can be invalid.

(1) Do not assume a DME signal remains valid just because it was valid when

acquired.

(2) Do not assume extra DME signals are available. The intent of this baseline is to

support operations where the infrastructure is mi nimal (for example, when only two DMEs are

available for parts of the procedure).

c. Use Stressing Conditions to Test Effectiveness. When an applicant uses a

reasonableness check to satisfy a ny requirement in this AC, they must test the effectiveness of

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03/01/07 AC 90-100A

Appendix 1

the check under stressing conditions. An example of this condition is a DME signal that is valid

at acquisition and ramps off during the test (similar to what a facility under test might do), when

there is only one other supporting DME or two signals of equal strength.

4. PERFORMANCE CONFIRMATION PROCESS.

New systems may demonstrate compliance with th ese criteria as part of the airworthiness

approval. For existing systems, the manufacturer should determine compliance with the

equipment and aircraft criteria in this a ppendix. Manufacturers w ho have achieved their

compliance should provide this information by lette r to their customers. Operators/pilots may

use this approval as a basis for their operations . Manufacturers are also requested to provide a

copy of this letter to Flight Technologies and Procedures Division, AFS-400, (202) 385-4586, to

facilitate making this information available to all operators. Guidance is provided below for both

an airplane manufacturer a nd FMS and DME manufacturers.

a. Airplane manufacturer (Type Certific ate (TC) holders incorporating FMS and

DME/DME positioning). The manufacturer should review the available data for the integrated

navigation system, and obtain addi tional data as appropriate, to determine compliance with the

criteria in this AC. Those ma nufacturers who have achieved comp liance with the criteria should

provide this information by letter to their customers. Manufac turers are also requested to

provide a copy of this letter to AFS-400, to facilitate making this information available to all operators.

b. Equipment manufacturers (typically separate Technical Standard Order (TSO) DME and FMS holders).

(1) DME Sensor . The only requirement in this append ix that needs to be considered for

a DME sensor is the accuracy requirement. DME se nsors have been demonstrated to a variety of

performance requirements per TSO-C66, Distan ce Measuring Equipment (DME) Operating

within the Radio Frequency Range of 960-1215 Megahertz.

(a) TSO-C66 performance standards have evolved as follows:

(i) TSO-C66: (Aug 1960) RTCA/DO99.

(ii) TSO-C66a: (Sep 1965) RTCA/DO151, accuracy requirement as total error

with 0.1 NM attributed to ground facility, airb orne equipment accuracy of 0.5 NM or 3% of

distance, whichever is greater , with a maximum of 3 NM.

(iii) TSO-C66b: (Nov 1978) RTCA/DO151a , accuracy requirement as total

error with 0.1 NM attributed to ground facility, airborne equipment accuracy of 0.5 NM or 1% of

distance, whichever is greater , with a maximum of 3 NM.

(iv) TSO-C66c: (Sept 1985) RTCA/DO189, accu racy requirement as total error

for the airborne equipment of 0.17 NM or 0.25% of distance, whichever is greater.

Page 5

AC 90-100A 03/01/07

Appendix 1

(b) The accuracy required by TSO-C66c is adequate to support the criteria in this

appendix, and DME equipment manufacturers under these versions of the TSO do not need to

further evaluate their equi pment for RNAV 1 and RNAV 2 operations. DME sensor

manufacturers may use the following process to establish more accurate performance than

originally credited.

(i) Determining Achieved Accuracy. Rather than relying on original

demonstrated performance, the applicant may elect to review the original TSO or TC/STC test

data to determine the demonstrated accuracy and/or make any appropriate changes to

qualification tests to de termine achieved accuracy.

NOTE: When conducting accuracy analysis, the DME signal-in-space error can be assumed

to be 0.1 NM 95% (both inside and outside the published service volume). If demonstrating

accuracy under bench or flight test conditions th e actual accuracy of the bench equipment or

ground facility should be considered.

(ii) Accomplishing New Testing. New tes ting should be performed under the

same conditions used to demonstrate complia nce with the original TSO-C66 standard.

(iii) Manufacturers who have demonstrated more accurate DME performance

should state the demonstrated accuracy in a letter to their customers. Manufacturers are also

requested to provide a copy of this letter to AFS-400 to faci litate making the information

available to all operators.

(2) Multi-Sensor Systems (FMS). The manufacturer should re view the available data

for the integrated navigation system, and obtain additional data as appropriate, to determine

compliance with the criteria in this appendix. Manufacturers who have determined compliance

should state such in a letter to their customers, along with any operational limitations (for

example, if the pilot is expected to manually inhibit the use of facilities which are listed by

NOTAM as unavailable). The manufacturer’s certification may limit the compliance to specific

DME systems, or may reference any DME qualified to the accuracy require ments of TSO-C66c.

Manufacturers should also provide a copy of this letter to AFS-400.

(a) FMS accuracy is dependent on a number of factors , including latency

effects, the selection of DME facilities, the method of combining information from multiple

DMEs, and the effects of other sensors used to determine a position. For FMSs using two (or

more) DMEs at the same time and limiting the DME include angle to between 30 and 150 °, the

accuracy requirement can be met if the DME sensors meet the accuracy requirements of

TSO-C66c. For FMSs without these characteristics, the accuracy should be evaluated under

poor DME geometry scenarios and should consider the demonstrated DME sensor accuracy. Poor geometry scenarios may include angles at the limits specified ear lier, with or without

additional DME facilities availa ble outside those conditions.

(b) Identify those conditions that would result in failure to meet the accuracy

requirement, and the means to prec lude those identif ied conditions.

Page 6

03/01/07 AC 90-100A

Appendix 2

APPENDIX 2. CRITERIA FOR APPROVAL OF BASELINE AREA NAVIGATION

(RNAV) SYSTEMS USING DISTANCE MEASURING EQUIPMENT (DME)

1. AND INERTIAL REFERENCE UNIT (IRU)

1. PURPOSE.

This appendix defines a minimum DME/DME/IRU (D/D/I) RNAV system baseline performance

capable of supporting RNAV 1 and RNAV 2 routes , as well as RNAV 1 Departure Procedures

(DPs) and Standard Terminal Arrivals (STARs). For routes and procedur es designed using this

performance standard, the FAA will decide if ad equate DME coverage is available using FAA

computer modeling and flight inspection assets. This assessment of DME coverage will also

determine if an Expanded Service Volume (ESV ) is necessary for select DME facilities.

2. MINIMUM REQUIREMENTS FO R DME/DME/IRU RNAV SYSTEM.

a. The minimum requirements of Appendix 1 apply and are not repeated in Appendix

2, except where additional performance is required. The performance confirmation process

in Appendix 1, paragraph 4, applies to appendix 2.

b. No Requirement to Use VOR, NDB, LOC, or AHRS. There is no requirement to use

VOR (VHF omni-range), NDB (non- directional beacon), LOC (localizer), or AHRS (attitude

heading reference system) during normal operation of the DME/DME/IRU RNAV system.

c. Position estimation error. Given any two DME facilities satisfying the criteria in

Appendix 1, subparagraphs 2b, 2c, and 2d, and any combination of other valid DME facilities

not meeting that criteria, the 95% position estimation error must be better than or equal to the

value obtained using the equation refere nced in Appendix 1, subparagraph 2f..

NOTE: In order to take full advantage of the inertial coas ting capability during gaps in

DME/DME coverage, it is necessary to define the best possible baseline for the DME/DME

performance at the beginning of the coverage gap. This baseline needs to take into account the DME geometry and performance at that time to provide as much margin as

possible, thereby allowing the most time fo r INS coasting. This equation assumes the

airborne equipment satisfies the a ccuracy requirements of TSO-C66c.

d. Inertial Performance.

(1) Inertial system performance must satisfy the criteria of 14 CFR Part 121, Appendix G.

NOTE: Based on an evaluation of IRU performance, the growth in position error after reverting to IRU can be expected to be less than 2 NM per 15 minutes.

e. Additional FMS Capabilities.

(1) Automatic position updating from the DME/DME solution is required.

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AC 90-100A 03/01/07

Appendix 2

NOTE : Operators/pilots should contact manufacturers to discern if any

annunciation of inertial coasting is suppressed following loss of radio updating.

(2) Must be able to accept a position update immediately prior to takeoff.

(3) Must exclude VORs greater than 40 NM from the aircraft.

f. Minimum Performance Standard for each Route or Procedure. The total system

error must be less than or equal to 1.0 NM (95% ) throughout the route. In order to maximize the

amount of IRU coasting allowed, the flight tech nical error for D/D/I aircraft on terminal

procedures should be limited to 0.5 NM (95%).

NOTE: The FAA assures that systems mee ting the D/D/I RNAV minimum performance

standard satisfy this requirement on all iden tified routes and procedures, and these RNAV

systems do not require further evaluation. Systems seeking approval using different RNAV

system characteristics or performance must de monstrate this perform ance for each published

route or procedure.

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03/01/07 AC 90-100A

Appendix 3

APPENDIX 3. NAVIGATION DISPLAYS AND FUNCTIONS

1. Navigation data, including a to/from indication a nd a failure indicator, must be

displayed on a lateral deviation display such as CDI, (E)HSI and/ or a navigation map display.

These shall be used as primary flight instrument s for the navigation of the aircraft, for maneuver

anticipation and for fa ilure/status/in tegrity indication. They shall meet the following

requirements:

a. Non-numeric lateral deviation display (for example, CDI, (E)HSI), with a To/From

indication and a failure annunciatio n, for use as primary flight instruments for navigation of the

aircraft, for maneuver anticipati on, and for failure/statu s/integrity indication, with the following

five attributes:

(1) The displays shall be visible to the pilot and located in the primary field of view (±

15 degrees from pilot’s normal line of sight) when looking forward along the flight path.

(2) The lateral deviation scaling should agr ee with any alerting and annunciation limits,

if implemented.

(3) The lateral deviation display must also ha ve a full-scale deflection suitable for the

current phase of flight and must be based on the required total system accuracy.

(4) The display scaling may be set automatica lly by default logic or set to a value

obtained from a navigation database. The full-sc ale deflection value must be known or must be

available for display to the pilot commensu rate with en route or terminal values.

(5) The lateral deviation display must be au tomatically slaved to the RNAV computed

path. The course selector to the deviation di splay should be automatically slewed to the RNAV

computed path or the pilot must adjust the OBS or HSI selected course to the computed desired

track.

NOTE: The normal function of stand-alone GN SS equipment meets this requirement.

b. If using a navigation map display, it should give equivalent f unctionality to a lateral

deviation display as described above, (Appendix 3, paragraph 1.a. (1-5)), readily visible to the

pilot, with appropriate map scales (s caling may be set manually by the pilot).

2. The following system functions are requi red as a minimum within RNAV equipment:

a. The capability to continuously display to the pilot flying, on the primary flight

instruments for navigation of the aircraft (pri mary navigation display), the RNAV computed

desired path and aircraft position relative to the path.

b. For operations where the required flight crew is two pilots, means for both pilots to

verify the desired path and the ai rcraft position relative to the path.

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Appendix 3

c. A navigation database , containing current navigation data officially promulgated for

civil aviation, which can be updated in accordance with the Aeronautical Information Regulation

and Control (AIRAC) cycle and from which termin al airspace procedures can be retrieved and

loaded into the RNAV system. The stored resoluti on of the data must be sufficient to achieve the

required total system error. The database must be protected against p ilot modification of the

stored data.

d. The means to display the validity period of the navigation data to the pilot.

3. The means to retrieve and display data stored in the navigati on database relating to

individual waypoints and na vigation aids, to enable the pilot to verify the route/procedure to be

flown.

4. The entire RNAV segment of the DP or STAR to be flown must be extracted from the

navigation database. In this document, the RNAV segment begins at the first occurrence of a

named waypoint, track, or course and ends at the last occurren ce of a named waypoint, track, or

course. Heading legs, prior to the first named waypoint or after the la st named waypoint of a

procedure, are not part of the RNAV segment and do not have to be loaded from the database.

Similarly, direct-to-fix legs prior to the first na med waypoint of a procedure are not part of the

RNAV segment. While not required, the ability to extract the entire RNAV procedure, including

heading and direct-to-fix legs, from th e database is a recommended function.

5. The means to display the following items, either in the pilot’s prim ary field of view, or on a

readily accessible page on a multi-function control display unit (MCDU).

a. The active navigation sensor type

b. The identification of the active (To) waypoint

c. The ground speed or time to the active (To) waypoint

d. The distance and bearing to the active (To) waypoint

6. Where the MCDU is used to support accuracy checks by the pilot, the capability of

displaying lateral deviation with a resolution of at least 0.1 NM.

7. The capability for the navigation system to execute a “Direct to” function.

8. The capability for automatic leg sequencing with display of sequencing to the pilot.

9. The capability to execute procedures extracted from the onboard database including the capability to execute fly-over and fly-by turns.

10. The capability to execute leg tr ansitions and maintain tracks consistent with the

following ARINC 424 path terminators:

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a. The aircraft must have the capability to automatically execute leg transitions and

maintain tracks consistent with the following ARINC 424 path terminators, or their

equivalent:

• Initial Fix (IF)

• Course to Fix (CF)

• Direct to Fix (DF)

• Track to Fix (TF)

NOTE 1: Path terminators are defined in ARINC Specification 424, and their

application is described in more deta il in RTCA documents DO-236B and DO-201A.

NOTE 2: Numeric values for courses and tr acks must be automatically loaded from

the RNAV system database. However, automa tic CF capability is not required for

approval to fly: (1) all RNAV routes covered by this AC as these are constructed

using TF path terminators, or (2) those ODP s using a DF or TF path terminator for

the first segment.

b. The aircraft must have the capability to automatically execute leg

transitions consistent with VA, VM and VI ARINC 424 path terminators, or must

be able to be manually flown on a heading to in tercept a course or to go direct to another

fix after reaching a procedure-specified altitude.

c. The aircraft must have the capabi lity to automatically execute leg

transitions consistent with CA and FM ARINC 424 path terminators or the RNAV

system must permit the pilot to readily designate a waypoint and select a desired course

to or from a designated waypoint.

11. The capability to load a named RNAV rout e into an RNAV system from the database is

a recommended function. However, if all or pa rt of the RNAV route (not DP or STAR) is

entered through the manual entry of fixes from th e navigation database, a TF leg type must be

used to define the path between a manually en tered by name fix and the preceding and following

fixes.

12. The capability to display an indication of the RNAV system failure , including the

associated sensors, in the p ilot’s primary field of view.

13. For multi-sensor systems, capability for automatic reversion to an alternate RNAV sensor if

the primary RNAV sensor fails.

NOTE: This does not preclude providi ng a means for manual navigation source

selection.

14. Database Integrity. The navigation database should be obtained from a database supplier

holding an FAA Letter of Acceptance (LOA) in accordance with AC 20-153. This LOA

provides recognition of a data supplier’s complian ce with the data quality, integrity and quality

management practices of RTCA DO-200A, Standa rds for Processing Aeronautical Data. The

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Appendix 3

operator’s supplier (e.g., FMS manufacturer) must have a Type 2 LOA. Discrepancies that

invalidate a procedure must be re ported to the database supplier and affected procedures must be

prohibited by an operator’s notice to its flight crew. Aircraft operators should c onsider the need

to conduct ongoing checks of the operational navi gation databases in order to meet existing

quality system requirements.

NOTE: AC 20-153 contains pr ocedures for database LOAs.

15. It is recommended RNAV systems provide lateral guidance so aircraft remain within the

lateral boundaries of the fly-by transiti on area as defined in DO-236B, section 3.2.5.4.1.

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