AC 91-79A - Mitigating the Risks of a Runway Overrun on Landing

U.S. Department

of Transportation

Federal Aviation

Administration Advisory

Circular

Subject: Mitigating the Risks of a Runway

Overrun Upon Landing Date: 9/17/14

Initiated by: AFS-800 AC No: 91-79A

Change:

1. PURPOSE. This advisory circular (AC) provides ways for pilots and airplane operators to

identify, understand, and mitigate risks associated with runway overruns during the landing phase of flight. It also provides operat ors with detailed information that operators may use to

develop company standard operating procedures (SOP) to mitigate those risks.

2. AUDIENCE. This document provides guidance to pilots and flightcrews, airplane operators,

certificate holders, program manag ers, training providers, pilot examiners, and other support

personnel. Pilots, airplane operators, certificate holders, program managers, training centers, and

other support personnel should adopt the recommended procedures found in this AC to enhance awar eness of the risks inherent during the landing phase of flight and the mitigations to employ

to reduce the ri sk of a runway landing overrun.

3. APPLICABILITY. The focus of the content of this AC is primarily on operations not

covered by Safety Alerts for Operators (SAFO) 06012, Landing Performance Assessments at Time of Arrival (Turbojets). Any values or examples provided in this AC are estimated values. Consult manufacturer information for specific guidance applicable to a given airplane model. However, in the absence of specific landing performance data provided by the airplane’s manufacturer, the pilot/operator is encouraged to use the most conservative landing performance information presented in this AC. Further, the operator may consider these concepts as additional

information in conjunction with an operator’s specific operations specifications (OpSpecs) or management specifications (MSpecs) and the airplane’s pilot’s operating handbook (POH), or Airplane Flight Manual (AFM), as appropriate.

4. RELATED READI NG MATERIAL (current editions):

• AC 23 -8, Flight Test Guide for Certification of Part 23 Airplanes;

• AC 25 -7, Flight Test Guide for Certification of Transport Category Airplanes;

• AC 60 -22, Aeronautical Decision Making;

• AC 120- 71, Standard Operating Procedure s for Flight Deck Crewmembers;

• AC 121.195( d)-1, Operational Landing Distances for Wet Runways; Transport Category

Airplanes;

• Approach and Landing Accident Reduction (ALAR)/Runway Excursion Risk Reduction (RERR) Tool Kits;

• FAA -H-8083- 25, Pilot’s Handbook of Aeronautical Knowledge;

• FAA -H-8083- 3, Airplane Flying Handbook;

AC 91 -79A 9/17/14

• Flight Safety Foundation (FSF) ALAR Tool Kit; FSF ALAR Briefing Notes, 8.3,

Landing Distances; 8.4, Braking Devices; 8.5, Wet or Contaminated Runways; 6.4,

Bounce Recover -Rejected Landing; an d 2.1, Human Factors.

• Reducing the Risk of Runway Excursions, FSF;

• Safety Targeted Awareness Report (STAR), Overruns on Landing, from the European

Regions Airline Association (ERA) Air Safety Work Group;

• SAFO 06012, Landing Performance Assessments at Time of Arrival (Turbojets); and

• SAFO 10005, Go- Around Callout and Immediate Response .

5. BACKGROUND. According to Federal Aviation Administration (FAA) and National

Transportation Safety Board (NTSB) information, runway overruns during the landing phase of flight account for approximately 10 incidents or accidents every year with varying degrees of severity, with many accidents resulting in fatalities. The NTSB also concludes that because of the dynamics of a tailwind approach and landing, particularly on wet or c ontaminated runways,

the FAA should provide current and comprehensive guidance regarding the risks associated with tailwind landings and raise awareness of the reduced margins of safety during tailwind landing operations. Therefore, the NTSB recommended th at the FAA revise AC 91-79, Runway Overrun

Prevention, to include a discussion of the risks associated with tailwind landings and landings on

wet or contaminated runways.

a. Strategy . Focused training and testing of pilots and flightcrews, combined with

training-based scenarios, are the tools to preventing runway overrun events. Targeted emphasis

on training and checking during initial pilot certification , recurrent training , and checking events

must not merely be an academic event, but must be practical in or der to increase a pilot’s

recognition of a higher -risk landing operation.

b. Necessity of Training. Focused training and testing of pilots and flightcrews, combined

with training -based scenarios, are important tools for preventing runway overrun events.

c. Opera tor and Pilot Responsibility. Operators are responsible for developing training

programs, SOPs, and complying with all of the regulatory requirements for the flight. All pilots are responsible for knowing the operational conditions they will be encountering and being able to assess the impact of environmental situations on the airplane’s landing distance. This responsibility includes following company SOPs and/or industry best practices and exercising the highest level of aeronautical decision -making (ADM) to ensure the safety of the flight.

NOTE: This guidance pertains to the preflight planning requirements of

Title 14 of the Code of Federal Regulations ( 14 CFR) part 91, §§ 91.103,

91.1037, and 91.605; part 121, § 121.195; and part 135, § 135.385.

6. DISCUSSION—HAZ ARDS ASSOCIATED WITH RUNWAY OVERRUNS. In order to

develop risk mitigation strategies and tools, it i s important to identify hazards associated with

runway overruns. A study of FAA and NTSB data indicates that the following hazards increase the risk of a ru nway overrun:

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9/17/14 AC 91 -79A

• Unstabilized approach;

• High airport elevation or high -density altitude, resulting in increased groundspeed;

• Effect of e xcess airspeed over the runway threshold;

• Airplane l anding w eight;

• Landing beyond the touchdown point ;

• Downhill runway slope;

• Excessive height over the runway threshold;

• Delayed use of deceleration devices;

• Landing with a tailwind; and

• A wet or contaminated runway.

a. What is an Uns tabilized Approach? Safe landings begin long before touchdown.

Adhering to the SOPs and best practi ces for stabilized approaches will always be the first line of

defense in preventing a runway overrun. See Appendix 4, Unstabilized Approach Case Study, for

an example of an unstabilized approach that led to a runway overrun.

b. High Airport Elevation. High a irport elevation or high density altitude results in a

higher true airspeed (TAS), ground speed, and a corresponding longer landing distance,

compared to low airport elevation or low density altitude.

NOTE: For example, at 1,000 -ft airport elevation, with a land ing distance

factor ( see Appendix 1 , Suggested Procedures and Training Information ) of

1.05 to 1.10 (depending on runway condition), the crew should apply to the landing distance achieved at a sea- level airport elevation. The AFM/POH

usually includes the a djustment for this factor.

c. The Effect of Excess Airspeed. The pilot must be aware of airspeed during the approach

and of the targeted reference landing airspeed ( V

REF)/airspeed, plus wind gust adjustments, over

the runway threshold. An excessive approach s peed may result in an excessive speed over the

runway’s threshold, which may result in landing beyond the intended touchdown point as well as a higher speed from which the pilot must bring the airplane to a stop. (Refer to the current editions of FSF ALAR Briefing Note 8.3— Landing Distances , and Boeing’s Takeoff/Landing on

Wet and Contaminated Runways.)

(1) FSF ALAR Briefing Note 8.3. A 10 percent increase in final approach speed results

in a 20 percent increase in landing distance. This assumes a normal flare and touchdown (i.e., not

allowing the airplane to float to bleed excess airspeed).

(2) Example. R unway length available is 5,000 ft and the airplane’s AFM/POH certified

landing distance may be up to 3,000 ft at the correct airspeed at the threshold crossing point .

However, given a 10 percent increase in airspeed over the runway threshold, increasing the landing distance 20 percent , the resultant operational landing distance is now 3,600 ft

(1.20×3,000).

d. Airplane Landing Weight. Any item that affects the landing speed or deceleration rate

during the landing roll will affect the landing distance. The effect of gross weight on landing distance is one of the principal items determining the landing distance of an airplane. One effect

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AC 91 -79A 9/17/14

of an increased gross weight is t hat the airplane will require a higher landing speed. When one

considers minimum landing distances on a dry runway, braking friction is the main source of

deceleration. The minimum landing distance will vary in direct proportion to the gross weight.

NOTE: For ex ample, a 10 percent increase in gross weight at landing would

result in a 5 percent increase in landing velocity and a 10 percent increase in

landing distance. (Refer to the Pilot’s Handbook of Aeronautical Knowledge for more information.)

e. Landing Beyond t he Intended Touchdown Point. AFM/POH distances are based on a

touchdown point determined through flight -testing procedures outlined in the current editions of

AC 25-7 and AC 23-8. If the airplane does not touch down within the air distance included in the

AFM or POH landing distance, it will not be possible to achieve the calculated landing distance.

f. Downhill Runway Slope. A negative runway slope of 1 percent (downhill) increases

landing distance by 10 percent (a factor of 1.1). (Refer to FSF ALAR Briefing Note 8.3 and

Appendix 1, Table 1 -3, Sample Computation: Runway Length7,000 ft .)

g. Excessive Height Over the Runway Threshold – Threshold Crossing Height (TCH)

Greater Than 50 f t (Excess TCH). The certified landing distances furnished in the AFM are

based on the landing gear being at a height of 50 ft over the runway threshold. For every 10 ft above the standard 50 f t threshold height, landing air distance will increase 200 ft .

NOTE: For example, TCH of 100 ft increases the landing distance by about

1,000 ft (50 ad ditional ft divided by 10 = 5 X 200 ft landing distance increase

per each 10 ft above 50 ft TCH = 1,000 ft additional landing distance). (Refer to FSF ALAR Briefing Note 8.3.)

h. Delayed Use of Deceleration/Maximum Braking.

(1) For those airplanes so equipped, de celeration devi ces consist of spoilers,

thrust reversers, and brakes. The touchdown point is important since the wheel brakes are much

more effective in retarding the airplane than the air drag during t he airborne part of the

landing distance. The sooner t he airplane touches down and starts braking, the shorter the total

distance will be. The FSF ALAR Task Force found that delayed braking action during the landing rollout was involved in some of the accidents and serious incidents in which slow/delayed crew action was a causal factor. The FSF Runway Safety Initiative (RSI) team

found that improper use and malfunction of speed brakes, wheel brakes, and reverse thrust were significant factors in a number of runway excursion landing accidents.

(2) Prompt and proper operation of all means of deceleration ha s a major influence on

landing distances. Spoilers greatly decrease lift, dump the weight on the wheels, and thereby make the brakes effective. It should be noted that manual spoilers, operated by the pilot, involve a delay. Even 2 seconds at speeds of 200 ft/second (118 knots ( kts)) can increase the stopping

distance by almost 400 ft. Landing distance data in the AFM is typically based on a time

increment of 1 second between successive actions to manually deploy/en gage the deceleration

devices ( see Figure 1, Assumed Landing Time Delays in Deriving the Scheduled Landing

Distance) . A cons ervative approach is to add 200 ft to the landing distance for every second in

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9/17/14 AC 91 -79A

excess of 2 seconds to deploy the airplane’s deceleration devices. A prudent pilot will make a

reasonable adjustment to the airplane’s landing distance for any delay in employing the

airplane’s deceleration devices. Figure 2, Braking Devices on Stopping Energy and Stopping Distance, shows the relative effect iveness of each of the deceleration devices during the landing

roll (refer to FSF ALAR Briefing Note 8.4) .

FIGURE 1. ASSUMED LANDING TIME DELAYS IN DERIVING THE SCHEDULED

LANDING DISTANCE

• Segment 1. This segment represents the flight test measured average time from

touchdown to pilot activation of the first deceleration device. For AFM data expansion,

use the longer of 1 second or the test time.

• Segment 2. This segment represents the flight test measur ed average test time from

pilot activation of the first dece leration device to pilot activation of the second

deceleration device. For AFM data expansion, use the longer of 1 second or the test time.

• Segment 2 is repeated until pilot activation of all deceleration devices has been completed and the airplane is in t he full braking configuration.

NOTE: For approved automatic deceleration devices (e.g., autobrakes or

auto -spoilers, etc.) for which performance credit is sought for AFM data

expansion, established times determined during certification testing may be used without the application of the 1 -second minimum time delay described

in the appropriate segment above.

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AC 91 -79A 9/17/14

FIGURE 2. BRAKING DEVICES ON STOPPING ENERGY AND

STOPPING DISTANCE

FIGURE 3. THRUST REVERSE EFFECTIVENESS

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9/17/14 AC 91 -79A

FIGURE 4. SECONDS COUNT – REVERSE THRUST APPLICATION SEQUENCE

(BOEI NG PERFORMANCE TAKEOFF/LANDING ON WET, CONTAMINATED, AND

SLIPPERY RUNWAYS)

(3) Be conservative and add 20 percent to the rollout distance if the pilot does not

maintain maximum braking until the airplane reaches a full stop. Otherwise, if available, use

AFM data for less than maximum braking.

(4) For airplanes that do not have antiskid brakes, spoilers, or thrust reverse, caution

should be exercised. Excessive braking can lead to causing a tire failure or cause a skidding condition, leading to a runway excursion. Therefore, flying a stabilized approach and timely

application of deceleration devices are the keys to a safe landing.

NOTE: Example: Available runway 5, 000 feet ( ft), AFM landing distance

3,000 ft, at correct speed, and at 50- ft TCH, a total of 3 seconds to d eploy the

airplane’s deceleration devices, results in 1 second over the AFM landing distance assumed 2 seconds to deploy deceleration device will result in an

additional 200 ft operational landing distance, for a total of 3,200 ft.

i. Landing with a Tailwind – E ffect of a Tailwind on Landing Distance. The effect of a

tailwind on landing distance is significant and is a factor in determining the landing distance

required. Given the airplane will land at a particular airspeed , independent of the wind, the

princi pal effect of a tailwind on operational landing distance is the change in the ground speed at

which the airplane touches down.

(1) The effect of a tailwind will increase the landing distance by 21 percent for the first

10 kts of tailwind. (Refer to the Pilot’s Handbook of Aeronautical Knowledge , and the aircraft’s

AFM/POH d ata to determine if tailwind landing data is available for the airplane.)

(2) Tailwind landings affect all types of airplanes. For transport category airplanes, the

effect of tailwind is shown in the AFM landing distance information. For small airplanes,

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AC 91 -79A 9/17/14

tailwind landing data may not be provided. The FAA Small Airplane Directorate provided the

following tailwind performance information for a few small airplanes:

• Cessna 150, 152, note on the landing distance chart, “for operation with tailwinds

up to 10 knots, increase distances by 10 percent for each 2 knots.”

• TMB 850, note under landing distance table to “increase total distances of

30 percent for every 10 knots of tailwind.”

• The Cirrus and Columbia are two very popular piston airplanes. The Cirrus uses

the same note in the chart as Cessna . The Columbia is like the Diamond airplane

and offers factors for grass but not tailwinds.

NOTE: Remember to account for the effect of a tailwind on landing

distance, whether you are flying a large or small airplane.

(3) Tailwind example: Available runway 5,000 ft , AFM landing distance 3,000 ft, TCH

at 50 ft and at the correct airspeed with a 10 kts tailwind results in an increase in the operational

landing distance of 21 percent. This increase equates to an additional 630 ft which increases the operational landing distance to a total of 3,630 ft.

j. A Wet or Contaminated Runway. L anding distances in the manufacturer -supplied

AFM provide performance in a flight test environment that is not necessarily representative of

normal flight operations. For those operators conducting operations in accordance with specific FAA performance regulations, the operating regulations require the AFM landing distances to be factored to ensure com pliance with the pre -departure landing distance regulations . These factors

should account for pilot technique, wind and runway conditions, and other items stated above .

Pilots and operators should also account for runway conditions at the time of arrival ( TOA) to

ensure the safety of the landing . Though the intended audience of SAFO 06012 is turbojet

airplanes, it is highly recommended that pilots of non- turbojet airplanes also follow the

recommendations in SAFO 06012.

(1) The SAFO urgently recommends that oper ators develop a procedure for flightcrews

to assess landing performance based on conditions actually existing at the TOA, as distinct from conditions presumed at time of dispatch. Those conditions include weather, runway conditions, the airplane’s landing weight , landing configuration, approach speed, and the flightcrew deploys

deceleration devices in a timely manner.

(2) Once the actual landing distance is determined, an additional safety margin of at least

15 percent should be added to that distance. Except under emergency conditions, flightcrews should not attempt to land on runways that do not meet the assessment criteria and safety margins as specified in SAFO 06012.

(3) A safety margin of 15 percent should be added, and the resulting distance should be

within the runway length available. T he FAA considers a 15 percent margin to be the minimum

acceptable safety margin.

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9/17/14 AC 91 -79A

NOTE: The flightcrew should not apply this 15 percent safety margin to

the landing distance determined for complia nce with any other

OpSpec/MSpec requi rement.

(4) Know you can stop within the landing distance available. The cumulative effect of the

conditions tha t extend the airplane’s landing distance, plus the 15 percent safety margin, can be a

substantial increase to the AFM/POH data , unless the pilot is aware of the items presented, and

possesses the knowledge and flying discipline to mitigate the risk of a runway overrun.

See below Table 1 , The Effects of Compound Factors —The End is Closer Than You Think.

TABLE 1. THE EFFECTS OF COMPOUND FACTORS —THE END IS CLOSER THAN

YOU THINK

7. RISK MITIGATION.

a. SOP. Specific SOPs to prevent a runway overrun are a primary risk mitigation tool. Once

SOPs are developed, it is imperative that the pilot/flightcrew execute them faithfully to mitigate

a runway overrun. As a mi nimum, the SOPs should contain the factors presented in this AC.

b. Runway Overrun Mitigation Training Curriculum. An effective training program is

the next tool that provides academic knowledge and skill to increase the pilot’s awareness of the factors that can cause a runway overrun. At a minimum, the operator’s training program should

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AC 91 -79A 9/17/14

include the same elements contained in their SOP . Also, the go-around maneuver and the reasons

to initiate a go -around maneuver must be part of their training. ( Refer to SAFO 10005.)

NOTE: Operators should also incorporate this training into their pilot and

dispatcher training for operations conducted in accordance with 14 CFR

parts 121, 135, 125, 91, 91K, 141, and 142. Further, all independent

certificated flight instructors (CFI) s hould also provide this training to the

pilots they train .

c. Flight Checking and Recurrent Training. Checking , testing, and recurrent training that

emphasizes airplane landing performance are essential tools to mitigate runway overruns.

Designated Pilot Examiners (DPE), flight and ground instructors, check airman, and dispatch examiners should specifically stress ADM , runway overrun risk management scenarios, and the

elements within this AC as they qualify , train pilots , flightcrews , and dispatchers to exerci se the

privileges of their certificate . Trainers and examiners must include runway overrun mitigation

strategies during training and checking to ensure the pilot/applicant can apply the principles in a real-world environment.

NOTE: The following appendices provi de additional information for

operators and pilots to develop SOPs, training programs, pilot techniques ,

and case study .

John Barbagallo

Acting Deputy Director, Flight Standards Service

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Appendix 1

APPENDIX 1. SUGGESTED PROC EDURES AND TRAINING INFORMATION

1. ORGANIZATIO N. This appendix divides the discussion of runway overruns during the

landing phase of flight into the following broad categories:

• Definitions;

• The necessity to fly a stabilized approach to the touchdown aiming point;

• A discussion of landing performance da ta; and

• Landing and braking techniques.

2. DEFINITIONS. The following, though not all inclusive, are definitions of landing elements

that form the foundation for a successful landing.

a. Declared Runway Distance. Declared distances for a runway represent the max imum

distances available and suitable for meeting takeoff and landing distance performance

requirements. All Title 14 of the Code of Fe deral Regulations (14 CFR) part 139 airports report

declared distances for each runway. For runways without published dec lared distances, the

declared distances may be assumed to be equal to the physical length of the runway unless there is a displaced landing threshold. (Refer to the Aeronautical Information Manual (AIM) for more information.)

b. Landing Distance Available (LD A). The length of the runway declared available for

landing. This distance may be shorter than the full length of the runway due to a threshold

displacement .

c. Actual Landing Distance. The landing distance for the reported meteorological and

runway surface c onditions, runway slope, airplane weight, airplane configuration, approach

speed, use of autoland or a Head -Up-Guidance System (HGS), and ground deceleration devices

planned to be used for the landing. It does not include any safety margin and represents t he best

performance the airplane is capable of for the conditions. (Refer to SAFO 06012, Landing

Performance Assessments at Time of Arrival (Turbojets), for more information.)

d. Braking Action Reports. When available, air traffic control (ATC) furnishes pilots the

quality of braking action received from pilots or airport management. The quality of braking action is described by the terms “good,” “fair (medium) ” (see note below ), “poor,” and “nil,” or a

combination of these. When pilots report the quality of braking action by using the terms noted above, pilots should use descriptive terms that are easily understood, such as “braking action is poor the first/last half of the runway,” and include the type of airplane. When tower controllers

have received runway braking action reports , which include the terms fair (medium) ( see note

below ), poor, or nil, or whenever weather conditions are conducive to deteriorating or rapidly

changing runway braking conditions, the tower will include on the automated terminal information service (ATIS) broadcast the statement, “Braking Action Advisories are in Effect.”

(Refer to the A IM for more information.) See Table 1- 1, Operational Runway Condition

Assessment Matrix (RCAM) Braking Action Codes and Definitions , below. (See the note s below

for the RCAM for clarification and information of terms and addition of codes.)

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AC 91 -79A 9/17/14

Appendix 1

NOTE: The braking action term “FAIR” is in the process of being changed

to “MEDIUM” throughout the Federal Aviation Administration ( FAA ).

Until an official language change is published, the current guidance of the

term “FAIR” is used.

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9/17/14 AC 91 -79A

Appendix 1

TABLE 1- 1. OPERATIONAL RUNWAY CONDITION ASSESSMENT

MATRIX (RCAM) BRAKING ACTION CODES AND DEFINITIONS

Airport Operator Assessment Criteria Control/Braking Assessment Criteria

Runway Condition Description Code Deceleration or

Directional Control

Observation Pilot Reported

Braking

Action

• Dry 6 --- ---

• Frost

• Wet (Includes damp and less than 1/8 inch depth of w ater)

Less than 1/8 inch (3mm) depth of:

• Slush

• Dry Snow

• Wet Snow 5 Brakin g deceleration is normal

for the wheel braking effort

applied AND directional control

is normal. Good

-15ºC and Colder outside air temperature:

• Compacted Snow 4 Braking deceleration OR

directional control is between

Good and Medium. Good to Medium

• Slippery When Wet (wet runway)

• Dry Snow or Wet Snow ( any depth) over Compacted Snow

1/8 inch depth or greater of:

• Dry Snow

• Wet Snow

Warmer than - 15ºC outside air temperature:

• Compacted Snow 3 Braking deceleration is

noticeably reduced for the

wheel braking effort applied OR

directional control is noticeably

reduced. Medium

1/8 inch depth or greater of:

• Water

• Slush 2 Braking deceleration OR

directional control is between

Medium and Poor. Medium

to

Poor

• Ice 1 Braking deceleration is

significan tly reduced for the

wheel braking effort applied OR

directional control is

significantly reduced. Poor

• Wet Ice

• Water on top of Compacted Snow

• Dry Snow or Wet Snow over Ice 0 Braking deceleration is minimal

to non- existent for the wheel

braking effor t applied OR

directional control is uncertain. Nil

Operational RCAM Version 2014.1

Note: The unshaded portion of the RCAM is associated with how an airport operator conducts a runway condition assessment.

Note: The shaded portion of the RCAM is associated with the pilot’s experience with braking action.

Note: The Operational RCAM illustration will differ from the RCAM illustration used by Airport Operators.

Note: Runway condition codes, one for each third of the landing surface, for example 4/3/3, represen t the runway condition

description as reported by the airport operator. The reporting of codes by runway thirds is expected to begin in October of 2016.

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AC 91 -79A 9/17/14

Appendix 1

e. Aiming Point. The aiming point is the point on the ground at which, if the airplane

maintains a constan t glidepath and does not execute the round out (flare) maneuver for landing, it

would touch the ground.

f. Maximum Braking Effort. Maximum braking effort is defined as maximum brake

application by the pilot.

g. Adjusted Landing Distance. Is the actual landing di stance adjusted for a landing safety

margin in accordance with the operator’s standard operating procedures (SOP). This should not

be confused with the landing distance associated with the dispatch requirements.

h. Target Touchdown Point. As discussed in the current edition of FAA -H-8083- 3,

Airplane Flying Handbook, the target touchdown point is defined as a touchdown point approximately 1,000 feet (ft) down the runway. Additionally, the operator may define the desired target touchdown point in their SOP.

i. Touc hdown Zone (TDZ). As referenced in the current edition of Airline Transport

Pilot (ATP) P ractical T est S tandards (PTS) FAA -S-8081- 5, Airline Transport Pilot and Aircraft

Type Rating Practical Test Standards for Airplane , the TDZ is r eferred to as a point 500- 3,000 ft

beyond the runway threshold not to exceed the first one -third of the runway. This reference is not

used in landing distance performance calculations.

j. Unfactored or Certified Landing Distance. The landing distance determined during

certification as required by 14 CFR part 23, § 23.75 and 14 CFR part 25, § 25.125. The

unfactored landing distance is not adjusted for any safety margin additives. The unfactored certified landing distance may be different from the actual landing distance because not a ll

factors affecting landing distance are required to be accounted for by certification regulations. For example, the unfactored certified landing distances are based on a dry, level (zero slope)

runway at standard day temperatures, and do not normally ta ke into account the use of

autobrakes, autoland systems, HGS, or thrust reversers. This is considere d the baseline

landing distance from which all subsequent user calculations emanate.

k. Factored Landing Distance. For applicable operations, the dispatch landi ng distance

allows the airp lane to land and stop within 60 percent of the available runway when the runway

is dry. The factored landing distance is the certified landing distance multiplied by 1.67, which can then be compared directly to the available land ing distance. When the runway is wet , the

certified distance is multiplied by 1.97 to account for the 15 percent additional runway requirement.

3. STABILIZED APPROACH TO THE TOUCHDOWN AIM POINT. A stabilized

approach is the safest profile, and it is one of the most critical elements to ensure a safe approach to a landing operation.

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Appendix 1

FIGURE 1-1. STABILIZED APPROACH

NOTE: The approach descent rate will vary given the airplane’s ground

speed as a result of the required approach speed per Airplane Flight

Manual (AFM), weight, and wind additives.

a. Landing Configuration. The airplane should be in the landing configuration early in the

approach. The landing gear should be down, landing flaps selected, trim set, and fuel balanced per the AFM or pilot’s operating handbook (POH). La nding checklist items should be

completed. Ensuring that these tasks are completed will help keep the number of variables to a

minimum during the final approach.

b. Stabilize d on Profile. The airplane should be stabilized on profile before descending

through the 1,000 -ft window or through the 500 ft above TDZ elevation (TDZE) window in

visual meteorological conditions (VMC). Configuration, trim, speed, and glidepath should be at

or near the optimum parameters early in the approach to avoid distractions and conflicts as the airplane nears the threshold window. The electronic or visual glidepath or an optimum glidepath

angle of 3 degrees should be established and maintained. For the purposes of this AC,

approaches that require a glidepath angle greater than 3 deg rees are a “special case.” The

airplane must be in the proper landing configuration, on the correct lateral track, the correct vertical track and at the proper airspeed. It should be noted, as it applies to stabilized approaches, that following lateral and vertical tracks should require only normal bracketing corrections.

NOTE: An approach that requires abnormal bracketing does not meet the

stabilized approach concept, and a go- around should be initiated.

c. Descent Rate. The optimum descent rate for a 3 degree appr oach path is based upon the

airplane’s ground speed. A pilot must exercise discipline and situational awareness to maintain the airplane’s target approach speed. The following is a method to estimate the appropriate

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Appendix 1

descent rate for a 3 degree descent path : Multiplying the ground speed in knots (kts) by 5

provides a usable target 3 degree descent rate in ft per minute. Combined with disciplined

airspeed control, slight adjustments in the rate of descent to maintain the glidepath will ensure

flying the descent/instrument landing system (ILS) glide path. For example, see Table 1- 2, Rates

of Descent Estimate Concept for a Three- Degree Glidepath vs. Ground Speed, and refer to the

ILS approach chart.

TABLE 1- 2. RATES OF DESCE NT ESTIMATE CONCEPT FOR THREE- DEGREE

GLIDEPATH VS. GROUND SPEED

Ground

speed kts 70 90 100 120 140 160

Published 30

GS fpm 372 478 531 637 743 849

5×GS

estimated

fpm 350 450 500 600 700 800

d. Indicated Airspeed. Indicated airspeed should be not more than V REF + 5 or the POH

published approach airspeed, with appropriate adjustments for wind or other factors, and never

less than V REF or the appropriate airspeed in order to avoid the loss of aircraft control. There is a

strong relationship between trim, speed, and power, and it is important to sta bilize the speed in

order to minimize those variables.

e. Turbojet Engine Speed. The engine speed should be at a setting that allows best

response when and if a rapid power increase is needed. The stabilized approach parameters

should be confirmed at 500 ft (VMC) or 1,000 ft instrument meteorological conditions (IMC)

above airpor t TDZE. This is approximately 1 -2 minutes from touchdown. If the approach is not

stabilized at that altitude, a go -around/balked landing should be executed.

f. Touchdown Point. Extended f lare and runway slope are two factors that affect pilot

control of the touchdown point. Turbine airplanes should be flown onto the runway rather than being held off the surface as speed dissipates. A firm landing is both normal and desirable. The typical o perational touchdown point is in the first third of the runway, and it may be farther down

the runway than the 1,000 ft point. This additional distance should be accounted for in the landing distance assessment at time of arrival (TOA).

g. Downhill Runway Slo pe. Additionally, a negative runway slope affects the touchdown

point. According to the Flight Safety Foundation (FSF) Approach and Landing Accident Reduction (ALAR) Briefing Not e 8.3— Landing Distances, each 1 percent of runway down slope

increases the lan ding distance by 10 percent. Depending upon the airplane’s manufacturer,

runway slope may be included in the AFM/POH landing performance data.

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Appendix 1

TABLE 1- 3. SAMPLE COMPUTATION: RUNWAY LENGTH 7,000 FT

NOTE: When computing runway gradient, every 1.0 percent grade equals

approximately 10 percent change in effective runway length. Also, for

shorter runways, it does not take as large an elevation difference between

runway ends to result in a 3 percent gradient. For example: for a 3 percent

gradient for a 3,000- ft runwa y, the elevation difference between the runway

ends would only be 90 ft.

h. Factors that Contribute to a n Uns tabilized Approach.

(1) An ATC clearance that request s an airspeed in excess of those airspeeds normally

flown in the terminal area, and/or clearances that require an airplane to remain at altitude to a

point where intercepting the normal glidepath is difficult to achieve , pilots should be aware that

if they cannot achieve a stabilized approach profile, to advise ATC.

NOTE: A stabilized approach to landing is key to mitigating the risk of a

runway overrun. If the pilot determines that a stabilized approach cannot be flown, the approach should not be accepted and a go -around should be

initiated.

(2) It is paramount that the airplane arrives at the approach threshold wi ndow on speed. If

the pilot has planned to carry additional airspeed beyond the threshold due to gusty surface wind conditions, then the effect of this additional airspeed/ground speed should be included in the actual landing distance. A balked landing man euver should be executed if the airplane does not

cross the runway threshold at the planned airspeed.

NOTE: A 10 percent excess lan ding speed causes at least a 21 percent

increase in landing distance. The excess speed places a greater working load

on the brakes because of the additional kinetic energy to be dissipated. Also, the additional speed causes increased drag and lift in the normal ground attitude, and the increased lift reduces the normal force on the braking surfaces. The deceleration may suffer during this range of speed immediately after touchdown, and it is more probable for a tire to be blown out from braking at this point.

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Appendix 1

4. DISCUSSION OF LANDING DATA.

a. Landing Performance Assessment. Landing performance assessment is influenced by a

multitude of varia bles. Airplane weight and configuration, use of deceleration devices,

airport elevation, atmospheric temperature, wind, runway length, runway slope, and runway

surface condition (i.e., dry, wet, contaminated, improved, unimproved, grass, etc.) are all fact ors

in determining landing performance. The condition of airplane tires, brakes, and systems

installed/operative/inoperative (e.g., antiskid braking, propeller reversing, thrust reversers, etc.), and pilot abilities/technique all have a direct impact on th e airpl ane’s ability to come to a

full stop after touchdown. However, there is no one standard format in which airplane

manufacturers are required to provide this additional data. The pilot must be aware of the airplane’s landing data/performance. The pilo t must also obtain the most current runway

condition information within a reasonable time before initiating the approach phase of flight in order to assess the airplane operational landing distance to ensure that it does not exceed the landing distance ava ilable. To begin the assessment process of landing performance, we need to

first address some basic principles of landing performance.

b. Data Provided. The data provided in the AFM/POH may only provide unfactored

landing data, which does not reflect operational landing distances. The AFM landing data for most large airplanes operated in accordance with 14 CFR part 121 provide factored landing

distances . Some manufacturers provide advisory or supplemental performance data in the

AFM/POH which may account for c onditions such as a dry runway, a wet runway,

ground spoilers operative/inoperative, thrust reversers operative/inoperative, antiskid

operative/inoperative, propeller reverse, tailwind, and/or headwind. Also, it is very important to understand that the fac tors that affect the stopping ability of an airplane are cumulative.

c. AFM Performance Section. The following includes general example s of aircraft

performance factors required for certification, and inclusion in the airplane’s AFM. Landing performance is of primary interest in operating an airplane because it is a factor in defining the

runway length requirements. In addition to the importance of proper piloting technique, any factor that affects the landing velocity or deceleration during the landing roll w ill affect landing

distance.

(1) Factors Required to be Included in the Performance Charts:

• Pressure altitude,

• Standard Temperature,

• Gross weight,

• Wind, and

• Airplane configuration.

(2) For Small Airplanes Operation on Unpaved Runway Information. For airplanes

less than 6,000 pounds (2730 kg) maximum weight, the factors given below may be quoted in

the flight manual as an alternative to the scheduling of data derived from testing or calculation. It should be noted that these factors are intended to cover the range o f airplane types in this

category and are necessarily co nservative (refer to the current edition of AC 23-8, Flight Test

Guide for Certification of Part 23 Airplanes ).

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Appendix 1

TABLE 1- 4. SMOOTH, FLAT RUNWAY

Takeoff Landing

Dry Grass 1.2 1.2

Wet Grass 1.3 1.6

NOTE: If the runway is not smooth, the grass is very long or very short,

higher factors may be warranted. Very short grass = golf course length. Very

long grass = un -mowed field or high interstate highway median grass length.

(3) Landing D istances for L arge T ranspor t Airplanes. Landing distances for large

transport airplanes determined during certification tests are aimed at demonstrating the shortest performance distances for a given airplane weight with a test pilot at the controls . In addition,

they are established with full awareness that operational rules for normal operations require the

addition of factors to dete rmine minimum operational field lengths. Therefore, the landing

distances determin ed for large airplanes, under § 25.125, are much shorter than the la nding

distances achieved in normal operations. For small airplanes, under § 23.75 (reference AC 23-8),

prescribes the requirements to certify a small airplane landing performance, though the factors of

weight, speed, and pressure altitude are considered, t he factors that extend the landing distance

are not included. Therefore, given the factors that increase the airplane’s required landing distance, the pilot/operator should seriously consider the consequence of not assessing the landing distance required.

(4) Air C arriers and 14 CFR P art 91K Operators . To mitigate the risk of a runway

overrun, air carriers and part 91K operators are required by regulation to multiply the airplane’s

actual landing distance by a specified factor associated with a destination or alternate airport. All operations must mitigate the risk of a runway overrun by considering all the elements that affect the unfactored landing distance provided in the AFM/POH. This is to ensure that at the time arrival, the landing distance required will not exceed the landing distance available. (For the purpose of example, refer to the applicable part 91K , § 91.1037; part 121, § 121.195; and

14 CFR part 135, § 135.385 for more information.)

NOTE: Notwithstanding that non -air carriers/operators are not required by

regulation to use a factored landing distance, they are strongly encouraged to adopt a factored landing distance methodology to mitigate the risk of a runway overrun.

d. Minimum Landing Distance Prediction. In the prediction of minimum landing distance

from the AFM/POH data, the following should be addressed ( see paragraph 4 above and the

sample cumulative landing distance worksheet in Appendix 3 for more information):

• High airport elevation or high density altitude, resulting in increased groundspeed;

• Landing weight ;

• Excess airspeed over the runway threshold;

• Landing beyond the intended touchdown point ;

• Runway slope ;

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• Excessive height over the runway threshold;

• Delayed use of deceleration devices ;

• Tailwind landing ; and

• A wet or contaminated runway.

e. The Effe ct of Wind on Landing Performance. Figure 1-2, Effect of Wind on Landing

Performance, illustrates the general effect of wind by showing the percent change in takeoff or

landing distance as a function of the ratio of wind velocity to takeoff or landing spee d. For

example, a tailwind velocity that is 10 percent of the landing airspeed produces a general effect of a 21 percent increase in the landing distance. (Refer to the current editing of the Pilot’s

Handbook of Aeronautical Knowledge , FAA -H-8083- 25, Aircr aft Performance.)

NOTE: If the wind direction is variable (VRB) and a range is given, the

value that provides to most negative condition must be used in performance

calculations. If no range is given , the full value of the wind velocity must be

considered a tail wind, since the possibility of this exists on landing.

FIGURE 1-2. EFFECT OF WIND ON LANDING PERFORMANCE

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Appendix 1

FIGURE 1-3. BASIC LANDING DISTANCE CHART

FIGURE 1-4. CUMULATIVE TYPE OF LANDING CHART PLOTTING DENSITY

ALTITUDE, LANDING WEIGHT, HEADWIND/TAILWIND, AND OBSTACLE

CLEA RANCE

f. Stabilized Approach. Without the benefit on an AFM/POH performance chart that

accounts for the variables this AC is discussing, the concept in Figure 1 -1, Stabilized Approach,

provides an appreciation of the factors that increase the airplane’s lan ding distance, and it keeps

the pilot engaged in landing distance assessment.

(1) Figur e 1-2, Effect of Wind on Landing Performance, illustrates the general effect of

wind by showing the percent change in takeoff or landing distance as a function of the ratio of

wind velocity to tak eoff or landing speed.

(2) Figure 1-4, Cumulative Type of Landing Chart Plotting Density Altitude, Landing

Weight, Headwind/Tailwind, and Obstacle Clearance, provides the manufacturer’s airplane

performance data accounting for density al titude, landing weight, wind, and obstacle clearance

height. It also illustrates a performance chart which plots the cumulative effect of each condition as the pilot progresses to obtain the landing distance.

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g. Airplane Landing Weight. Calculate the anticipa ted landing weight by starting with the

airplane gross takeoff weight at departure and subtracting the anticipated normal consumption of

fuel required to arrive at the destination airport. If the en route fuel burn is less than planned, the

airplane will a rrive at its destination at a weight heavier than expected . Therefore, relative to the

airplane’s actual landing weight, a recalculation of the airplane’s landing performance is essential prior to attempting a landing maneuver to validate the dispatched la nding distance

available.

h. Extended Flaps. Flaps may be fully extended to give the airplane a lower stalling speed

during the approach to landing. This also allows the airplane to land in a shorter distance. The higher lift and drag associated with fully ex tended flaps produces greater drag permitting a

steeper approach. The greater lift permits a lower landing speed to the landing site but imposes handling difficulties in airplane s with very low wing loading (the ratio between the wing area

and the weight of the airplane). Winds across the line of flight, known as crosswind, cause s the

windward side of the airplane to generate more lift and drag, causing the airplane to roll, yaw, and pitch off its intended flight path. As a result, many light airplanes have limits on how strong

the crosswind can be while using flaps. Furthermore, once the airplane is on the ground, the flaps may decrease the effectiveness of the brakes since the wing is still generating lift and preventing the entire weight of the airplane f rom resting on the tires, thus increasing stopping distance,

particularly in wet or icy conditions. Thereby, usually the pilot will raise the flaps as soon as possible for airplanes without spoilers to prevent this from occurring under wet or icy conditions, and done with caution. Notwithstanding the possible effect of a full flap landing, achieving the target airspeed over the threshold, and flying the slowest approach speed for the wind conditions,

selecting the maximum flap setting approved by the airpla ne manufacturer will provide the

shortest operational landing distance.

i. Threshold Crossing Height and Airspeed. As previously discussed, the correct

threshold crossing airspeed is specifically defined. Therefore it is essential to understand the impact of deviations in threshold crossing airspeeds.

j. Critical Condition Combinations. The most critical conditions of landing performance

are combinations of:

• High gross weight, high density altitude,

• Wet/contaminated runway,

• Tailwind landing,

• Downhill slope,

• Less than maximum landing flap, and

• Short runway.

NOTE: In all cases, it is necessary to make an accurate prediction of

minimum landing distance to compare with the available runway.

5. LANDING AND BRAKING TECHNIQUE. The flare, touchdown, and the braking

technique, are also critical factors in completing a successful approach and landing maneuver. Landing and braking techniques are discussed below from a point at the beginning of the

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Appendix 1

approach flare through a point at which the airplane decelerates to normal taxi speed or has been

brought to a full stop.

a. The Flare. The flare reduces the approach rate of descent to a more acceptable rate for

touchdown. If the flare is extended while additional speed is bled off, additional runway will be

used. An extended flare may also res ult in an increase in pitch attitude which may lead to a tail

strike. A firm landing does not mean a hard landing, but rather a deliberate or positive touchdown at the desired touchdown point. A landing executed solely for passenger comfort considerations, which extends the touchdown point beyond the TDZ, is not impressive, desirable, or consistent with safety or regulations. It is essential to fly the airplane onto the runway at the target touchdown point. See Figure 1- 5, Effects of an Extended Flare, as a n example of the

results of an extended flare.

FIGURE 1-5. EFFECTS OF AN EXTENDED FLARE

b. Touchdown. A proper approach and flare positions the airplane to touch down at the

target touchdown point. Once the main wheels have contacted the runway, the pilot must maintain directional control and initiate the stopping process. The runway distance available to

stop is longest if the touchdown was on target. Once the airplane is on the ground, ground

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Appendix 1

spoilers, wheel brakes, and reversers (depending on airplane equipage) are much more effective

in slowing the airplane than the aerodynamic drag produced in the flare maneuver.

NOTE: General aviation airplane technique is to slowly apply backpressure

to the yoke to assist braking and to avoid damage to the nose gear or

propeller.

c. Braking. A distinction should be made between the procedures for minimum landing

distance and an ordinary landing roll with considerable excess runway available. Minimum landing distance will be obtained by creating a continuous peak deceleration of the ai rplane; that

is, extensive use of the brakes for maximum deceleration. On the other hand, an ordinary landing roll with considerable excess runway may allow extensive use of aerodynamic drag to minimize wear and tear on the tires and brakes. If aerodynamic drag is sufficient to cause deceleration, it

can be used in deference to the brakes in the early stages of the landing roll. For instance, brakes and tires suffer from continuous hard use, but airplane aerodynamic drag is free and does not wear out with use. The use of aerodynamic drag is applicable only for deceleration to 60 or 70 percent of the touchdown speed. At speeds less than 60 to 70 percent of the touchdown speed, aerodynamic drag is so slight as to be of little use, and braking must be utilized to produce continued deceleration. Since the objective during the landing roll is to decelerate, the powerplant thrust should be the smallest possible positive value (or largest possible negative value in the case of thrust reversers).

NOTE: In addition to prope r procedures, many other variables affect the

landing performance. Any item that alters the landing speed or deceleration rate during the landing roll will affect the landing distance.

(1) There are three primary forces available for deceleration during the ro llout process:

wheel braking, aerodynamic drag, and reverse thrust/propeller reversing, if available. The deployment of ground spoilers, if installed, immediately upon touchdown on the runway has the effect of dumping the lift generated by the wings and pl acing the airplane’s weight on the

wheels, which enhances the effects of wheel braking after touchdown. Deployment of drag devices are most effective at higher speeds and are not affected by runway surface conditions. In all cases, the pilot must ensure th e automatic deployment of the deceleration devices occurs. If

not, the pilot must immediately manually employ the devices to minimize the time lost to achieve as close as possible the assessed landing distance.

(2) Timely deployment of spoilers will increase d rag by 50 to 60 percent, but more

importantly, deployment of the spoilers increases wheel loading by as much as 200 percent in the landing flap configuration. This increases the tire -to-ground friction force making the maximum

tire braking forces available. Many airplanes with auto -spoilers installed require weight on

wheels to deploy the spoilers, which reinforces the requirement for a positive touchdown as a soft touchdown can delay the automatic deployment. Spoiler deployment immediately after touchdown provides the greatest benefit.

(3) When minimum landing distances are considered, braking friction forces predominate

during the landing roll and, for the majority of airplane configurations, braking friction is the main source of deceleration when the runway is dry.

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Appendix 1

d. Wet and Contaminated Runway Surface. When the runway is wet or slippery, reverse

thrust (if the airplane is equipped), may be the dominant deceleration force just after touchdown,

and throughout the deceleration if the runway has poor or worse braking conditions. As the airplane slows down, the wheel brakes become the dominate deceleration force. When the runway length is limited, for airplanes equipped with an antiskid system, maximum wheel braking should be applied immediately after touchdown. For airplanes without an antiskid

system slow back pressure should be applied to the yoke such that it will not raise the nose of a nose gear airplane for aerodynamic braking while maximum braking that will not cause skidding is applied. In all situations, br aking should be maintained until the airplane slows to a safe taxi

speed for the conditions.

e. Autobrakes. If the airplane is equipped with autobrakes, manufacturers recommend the

use of the autobrakes for all landings on contaminated runways. Autobrakes are applied earlier in

the landing roll, and to the level selected by the pilot for the anticipated landing condition, runway available, and provide the most efficient and timely use of braking action. However, the pilot must ensure that if the autobrakes do not engage upon touchdown, then manual braking must be applied.

f. Anti skid. Application of brakes is different for airplanes equipped with a functioning

antiskid braking system than for airplanes without such a system.

(1) For airplanes without an antiskid syste m, brakes should be applied progressively

throughout the deceleration process, and the pilot must recognize the point that wheel skid

occurs. Maximum braking effectiveness occurs just prior to the point where wheel skidding occurs. However, should a skid occur, releasing brake pressure can stop skidding and then maximum braking can be reestablished until the deceleration process is completed. Pilots should be aware that a skid is most likely at higher speeds and at that point may not be perceptible.

(2) For air planes with antiskid system, to achieve the benefits of antiskid, the brakes must

be applied firmly throughout the deceleration process. When maximum braking is required, it is accomplished by holding maximum brake application pressure and allowing the ant iskid system

to operate. Letting up on the brakes (unless required to regain directional control) defeats the purpose of the antiskid system. The pulsation caused by the modulation of the brake pressure by the antiskid system indicates that the antiskid sy stem is operating normally although the

pulsation may be disconcerting to the pilot.

g. Touchdown Technique. A firm touchdown at the target touchdown point, followed by,

for those airplanes so equipped, the deployment of ground spoilers, the timely selection of thrust reverse (if installed), and the application of max/progressively applied firm braking will result in the shortest landing distance ground roll, particularly on wet or contaminated runway surfaces.

h. Directional Control. The nosewheel should be lowe red onto the runway immediately

after touchdown. Placing the nosewheel on the runway will assist in maintaining directional control. It also decreases the wing angle of attack, thereby decreasing lift and placing more load onto the tires, which increases t ire-to-ground friction.

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i. Thrust Reversers. In the event of an asymmetric deployment, the nosewheel on the

ground will aid in directional control. If the thrust reversers deploy asymmetrically, or if the

airplane begins to drift due to a crosswind, close the thrust reversers and reestablish directional

control. Once the airplane’s track down the runway is reestablished, redeploy the thrust reversers. Use airplane steering in accordance with the AFM procedures.

6. SUMMARY. A stabilized approach terminating with a landing in the TDZ, timely

deployment of airplane deceleration devices, and braking technique are critical elements to mitigating the landing runway -overrun risk. It is a responsibility of operators to consider the

factors presented, and incorporate these items, as well as the extensive research and safety

information available regarding avoiding a runway overrun into training programs and operations manuals. It is the pilot’s responsibility to apply the landing assessment process, exercise conservative aeronautical decision -making (ADM) , be proficient in the landing

techniques for the conditions to be encountered, and that a go -around or diversion are mitigations

to prevent a runway overrun.

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Appendix 2

APPENDIX 2. REGULATORY CONSIDERATIONS AND RECOMMENDE D

OPERATIONAL PRACTICES

1. REGULATORY REQUIREMENTS FOR LANDING FOCUS ON PREDEPARTURE

FLIGHT PLANNING. The intent is to ensure that a flight operation does not begin that cannot

reasonably be safely concluded upon reaching the destination or alternate airport, as applicable.

Regarding regulations, there are differences in the various operating regulations concerning landing performance. Compliance with these regulations is shown using approved data from the Airplane Flight Manual (AFM).

NOTE: Some manufacturers supply advisory o r supplemental data that

provides landing performance data based on landing weight, airport elevation and temperature, corrected for wind (headwind, tailwind), and slope. Manufacturers may also supply advisory or supplemental data that accounts for runway condition (wet, dry, and contaminated) and braking

degradation (i.e., antiskid is inoperative, thrust reversers are inoperative,

etc.). Pilots and operators should be familiar with the data presented in their AFM, and they should be capable of applying bot h the approved data and

advisory or supplemental data to make operational decisions.

2. REGULATORY CONSIDERATIONS. It is not the intent of this advisory circular (AC) to

provide the regulatory requirements. However, operators and pilots must be knowledgeable of the operational regulations applicable to their type of operation. Figure 2 -1, Sections 121.195(b),

135.385(b), and 91.1037(b) 60-Percent Rule; Figure 2-2, Sections 121.195(d), 135.385(d), and

91.1037 Wet Runway 115- Percent Rule; and Table 2 -1, Regulatory Planned Landing Distance

Calculations Overview, provide a regulatory overview of airplane landing performance

requirements applicable to flight operations conducted in accordance with Title 14 of the Code of

Federal Regulations ( 14 CFR ) parts 91K , 121, and 135.

FIGURE 2-1. SECTIONS 121.195(B), 135.385(B), AND 91.1037(B) 60- PERCENT RULE

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Appendix 2

NOTE: Part 91, § 91.1037 states, in part: “(e) Unless, based on a showing of

actual operating landing techniques on wet runways, a shorter landing

distance (but never less than that required by paragraph (b) or (c) of this

section) has been approved for a specific type and model airplane and included in the Airplane Flight Manual , no person may take off a turbojet

airplane when the appropriate weather reports or forecasts, or any

combination of them, indicate that the runways at the destination or

alternate airport may be wet or slippery at the estimated time of arrival

unless the effective runway length at the destination airport is at least 115 percent of the runway length required under paragraph (b) or (c) of this section. ”

FIGURE 2-2. SECTIONS 121.195(D), 135.385(D), AND 91.1037 WET RUNWAY

115-PERCENT RULE

NOTE: Calculations depicted in Table 2-1 are preflight planning

calculations. When the flight arrives at the destination, 100 percent of the effective runway length is available for landing. It should be noted that operators with operations specifications (OpSpecs) and management specifications (MSpecs) must complete these calculations in accordance with

those directives . 1.67

/ Factor 1.97

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Appendix 2

TABLE 2- 1. REGU LATORY PLANNED LANDING DISTANCE CALCULATIONS

OVERVIEW

Regulation Type of Airplane Runway

Condition Percentage of Effective

Runway Length

§ 121.195(b)

§ 135.385(b)

§ 91.1037(a) Large turbine powered Dry 60 percent

§ 121.195(c)

§ 135.385(c) Turbopropeller

alternate airport Dry 70 percent

§ 121.195(d)

§ 135.385(d)

§ 91.1037(e) Turbojet without an

approved AFM wet runway

landing technique Wet/Slippery 115 percent of § 121.195(b) or

§ 135.385(b), or § 91.1037(e)

AFM factored dry landing

distance

§ 135.385(f)

§ 91.1037(c)(2) Large turbine powered,

eligible on demand OpSpecs/MSpecs

Authorized 80 percent

§ 121.197

§ 135.387(a) Large turbine powered

alternate airport Dry 60 percent

§ 121.197

§ 135.387(a) Turbopropeller

alternate airport Dry 70 percent

§ 135.387(b)

§ 91.1037(3)(d) Large turbine powered,

eligible on demand

alternate airport OpSpecs/MSpecs

Authorized 80 percent

NOTE: For part 125 operators, it is highly recommended that they adopt

the stated regulatory requirements contained in Table 2 -1 above.

a. Part 91 Operational Recommendations.

(1) Preflight planning requirements for part 91 operators are governed by §§ 91.103

and 91.605. It is highly recommended that part 91 operators, and pilots calculate predeparture

landing distance performance requirements based on the guidance contained in their AFM, and

employ the landing assessment process before initiating the approach landing phase of the flight,

and consider the factors presented in this AC to avoid a runway overrun.

(2) To ensure that an acceptable landi ng distance safety margin exists at TOA, the FAA

recommends a 15 percent safety margin be applied to the actual airplane landing distance. The

15 percent safety margin is a minimum safety margin to be applied after accounting for all known variables, such as the meteorological , runway surface conditions, landing with a tailwind,

airplane configuration and weight, runway slope, threshold crossing height and airspeed, and the timely utilization of ground deceleration devices. Be prepared, know the landing conditions, divert to an alternate, or go around, but do not risk a runway overrun.

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Appendix 3

APPENDIX 3. OPERATIONAL AWARENES S OF WET AND CONTAMI NATED

RUNWAYS LANDING DIST ANCE DATA

1. MANUFACTURERS AND AIRPLANE FLIGHT MANUAL (AFM) DATA. In

accordance with Federal Aviati on Administration (FAA) certification rules, the FAA -approved

AFM data are determined only for dry runway conditions. Some manufacturers provide

supplemental FAA -approved AFM data for operation on wet grooved runways. Manufacturers

may also provide supplem ental advisory landing distance data for conditions beyond those

required by regulation; however, they are not used in lieu of the advised 15 percent safety

margin. The data contained in these supplements, although not FAA approved, are based on the same f light test data used to generate the FAA -approved dry runway takeoff and landing

performance presented in the AFM. Performance is calculated using analytical corrections to dry runway performance utilizing methods appropriate for aircraft certification out side the

United States. Again, at least a 15 percent safety margin should be applied to these data.

2. METHODS USED TO ADJUST DRY RUNWAY PERFORMANCE. The analytical

methods employed to adjust the dry runway performance to account for conditions encountered on wet and contaminated runways are complex and comprehensive. The methods utilized include adjustments for changes in the braking coefficient, precipitation drag, and hydroplaning, as applicable.

3. BRAKING COEFFICIENT. The braking coefficient is a measure of the braking efficiency

at the contact point between the airplane main tires and the runway. The braking coefficient is

the ratio of braking force divided by the weight on the tire. A tire supporting 5,000 pounds with a braking coefficient of 0.5 would be c apable of producing 2,500 pounds of stopping force. As

contaminants are introduced onto the runway, the braking coefficient is reduced, decreasing the stopping capability of the airplane.

NOTE: For example, a wet runway typically will reduce the braking

coeffici ent by about 50 percent. Runways contaminated with dry snow

typically can reduce the braking coefficient do wn to about 0.10, or only

20-25 percent of the braking capability of a dry runway. In other words, the

2,500- pound stopping force on a dry runway may now be only

500-600 pounds on dry snow.

4. PRECIPITATION DRAG. Precipitation drag comprises two components: precipitation

impingement drag and precipitation displacement drag.

a. Precipitation Impingement Drag. Precipitation impingement drag is the force create d

as contaminant spray from the tires impacts parts of the airframe, such as the flaps behind the main gear. Impingement drag assists in slowing the air plane and resists acceleration.

b. Precipitation Displacement Drag. Precip itation displacement drag is a resistance force

created as the tires push runway contaminant out of the way while moving along the runway.

c. Example. It is the force you feel when trying to move your hand rapidly through water.

As your hand moves the water is forced out of the way , and t he faster you try to move your hand,

the stronger the resistance. Runway contaminants act much the same way. The resultant

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AC 91 -79A 9/17/14

Appendix 3

resistance force assists in slowing the airplane during landing or a rejected takeoff, and also

resists acceleration during takeo ff.

NOTE: Som e manufacturers do not include the effects of precipitation drag

on landing distances. However, if the effect of precipitation drag is included

in the landing distance performance for the airplane , it has the non -intuitive

characteristic. This means that g iven a conservative approach to assessing

the airplane’s landing distance due to precipitation drag, if a deeper

contaminant level is selected with the intention of being conservative, the

result will be the opposite —it will be non -conservative. If less co ntaminant is

actually there, it will result in a longer distance than calculated.

5. DETERMINE THE RUNWAY SURFACE CONDITION. Appropriate determination of

the runway surface condition is basic to the m itigation of a runway overrun. Once the surface

condition i s determined, it is a pilot’s responsibility to decide whether the standard AFM dry

runway performance charts are appropriate or whether the wet and contaminated performance data needs to be consulted. In preparing for takeoff, this decision is considerabl y easier since the

pilot can visually survey the runway. The standard dry runway charts are for a totally dry runway.

NOTE: For example, if the ramp is too damp to sit on due to morning dew,

the runway is probably the same. The pilot should use the wet or contam inated performance data.

6. DATA REVIEW . When reviewing takeoff and landing data, the pilot should pay attention

to the details, and select the correct chart. In many cases this is obvious, but there may be conditions, or combinations of conditions, that can make the selection problematic. Careful review of Aviation Routine Weather Report (METAR) or other airport reports may provide sufficient information to make the proper selection. At airports where automated terminal information service (ATIS) is available , surface contamination reports may be included that can

be used as a guide. At other airports, no information may be available. Regardless of the source, it is prudent to utilize the information that yields the most conservative performance. If reports indicate mixed runway conditions such as snow and slush, use the chart for the contaminant that

results in the longest distance . If no reliable information is available, use the chart for the

reasonably likely condition that provides the longest distance.

NOTE: If you choose to land with a tailwind, a tailwind is a significant

factor that increases an airplane’s landing distance. Selection of a runway condition that renders a shorter distance should only be based on factual

information. The pilot should resist the temptation to use a less severe

runway contamination condition simply because it produces a landing distance that is equal to or less than the available runway length.

NOTE: Runway overrun mitigation implies, if the landing assessment

reveals that the runway len gth available is not long enough to safely land and

stop the airplane, change to a longer runway, or even divert to a different airport.

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Appendix 3

7. RUNWAY SURFACE CONDITIONS BEYOND DATA COVERAGE. There are runway

surface conditions, such as wet ice, that are worse th an the wet and contaminated data provided

in the airplane’s landing performance AFM . Even the most effective braking systems are

ineffective in the presence of a near zero braking coefficient.

NOTE: For example, with a zero or near zero braking coefficient, the

rolling friction coefficient of all the tires is near zero. Nosewheel steering will

be ineffective, and the pilot will not be able to correct for any side force on the airplane, such as a crosswind . Given this reported runway condition, the

flight should divert to a n airport where the better landing conditions are

reported.

8. OPERATIONS AT NON- TOWERED AIRPORTS. Operations at non- towered airports

require pilots to gather available information on expected runway conditions prior to initiating an approach.

NOTE: For e xample, if there is no clear report of runway condition (s), but

the pilot knows rain has been in the area, that pilot should assume the runway is wet . Also , if there is rain actively falling on the runway, standing

water should be assumed. If there is any doubt as to the amount of water on the runway, assume the most conservative condition that requires the longest landing distance.

9. DECELERATION. Once committed to an operation on a wet or contaminated runway, the

pilot should expect a lower level of deceler ation than experienced on a dry runway.

NOTE: For example, consider the landing distances for wet and

conta minated surfaces, assuming zero wind and a zero runway gradient.

Then add the distance effect of a tailwind , downhill runway gradient,

additional speed, an d delay ed use of deceleration devices. Under these

conditions, a wet runway increases the landing distance over a dry runway by approximately 26 percent. If standing water is present, the landing distance increases approximately 52 percent.

NOTE: The contaminant only affects the ground roll and braking. It has no

impact on the air distance from 50 feet (ft) to touchdown, which is included

in the landing distance. In the presence of standing water, for the total landing distance to increase 52 percent, the ground braking distance

increases 100 percent. This situation will surprise a pilot the first time it is

encountered because the deceleration rate on this surface will be only

one-half of what the pilot has experienced on a dry runway.

10. CONTAMINANT PROCEDURES. For any contaminant, the pilot should expect a

relatively low deceleration rate in the initial phase of braking. A wet runway may be less severe

than other contaminants, but the pilot must remember that any increase in total landing distance will occur entire ly in the landing ground roll braking segment.

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Appendix 3

NOTE: Under some conditions, wet runways have exhibited significantly

worse than expected braking, and the reason for this is not yet understood.

11. HYDROPLANING. Hydroplaning is defined as a condition that exists when the tires ride

on the surface of the conta minant, much like a water ski. When the tires are hydroplaning,

directional control and braking action are virtually impossible. An effective antiskid system can

minimize the effects of hydroplaning. See Figure 3 -1, Hydroplaning .

FIGURE 3-1. HYDROPLANING

a. Hydroplaning. Hydroplaning is a significant factor that should be considered in

determ ining stopping capability on a contaminated runway . Hydroplaning depends on

wheel speed and tire pressure. The key item to remember when the airplane is hydroplaning is

that the tires are no longer in contact with the runway, although the airplane is not a irborne.

Though at high speeds, aerodynamic drag can provide a significant decelerating force. Reverse thrust/propeller reversing, if installed, provides nearly all the decelerating force when

hydroplaning since the brake s are essentially ineffective. Thes e characteristics are included in the

distances presented in the contaminated runway supplemental data when provided by the

airplane manufacturer.

b. Directional Control. It is very important to realize that directional control has not been

demonstrated on these surfaces. The pilot should expect significant degradation in directional

controllability on a contaminated runway, depending on the level of available runway friction,

especially with an engine shut down or with a crosswind. Some manufacturers provide maximum crosswind values, derived through simulation and calculation, for landing on contaminated runways.

NOTE: Runway surface conditions are rarely consistent over the full length

of the runway. Even dry runways will present different friction coefficients due to heavy rubber deposits in the touchdown zone (TDZ) and large paint

markings such as the 1,000- foot markers or centerline stripes. The degree of

runway surface contamination due to ice, packed snow, or standing water

varies along the length of the runway. The pilot will sense changes in the deceleration rate as the airplane transitions from one contaminant condition to another.

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Appendix 3

12. BRAKE FAILURE VERSUS REDUCED BRAKING. How does the pilot differentiate

between reduced braking capability and a brake failure wit h reduced, and occasionally very low,

deceleration rates due to runway contamination? The best answer is for the pilot to be thoroughly

familiar with all operating characteristics of the airplane. Experience is the best tool, and until the pilot has the ex perience, training and knowledge of aircraft performance is the best tool . All

pilots should take advantage of the opportunity to experience braking capability in the simulator on different contaminants when possible. While decelerating, scan the airspeed display in order to relate the change in speed to the kinesthetic perceptions. During the period of maximum brake application after touchdown, the antiskid system is working to keep the tires on the verge of a skid. The pilot may perceive small, abrupt pul ses as the tires occasionally get a solid grip prior to

skidding, followed by a short release of brakes to allow the tires to spin up again. As the surface condition becomes more challenging, the antiskid system will command longer brake releases to mainta in a proper level of friction between the tire and the runway. As the airplane decelerates,

the braking effectiveness will increase but may never attain dry runway levels. As long as the pilot senses the cycling of the antiskid system, the pilot knows the brakes are performing to the maximum extent permitted by the runway surface condition.

NOTE: The pilot cannot modulate the brakes better than the antiskid

system. Pilot response time to the changing conditions is measured in seconds, and the antiskid system can adjust in milliseconds. The best braking performance will occur when the pilot presses hard on the brake pedals and

maintains a constant pressure. Let the antiskid do all the modulation but be

sensitive to that same anti skid operation. Be perceptive and ma ke note of the

antiskid pulses. That is the pilot’s firsthand knowledge of proper brake operation.

13. PERFORMANCE DATA NOTES. Every pilot should read and understand the

information presented in the contaminated runway supplemental data before using the inform ation to calculate performance. When the pilot thoroughly understands the operation of

the antiskid system, becomes familiar with the runway condition at the destination, and completes and applies conservative landing distance calculations, the pilot will mitigate the risk of a runway overrun.

14. TABLES FOR RUNWAY MITIGATION. These tables are included to assist the pilot in

the application of the concepts presented to mitigate the risks associated with the hazard of a runway overrun. Table 3- 1, Memory Jogger: Can You Stop?; Table 3-2, All Factors Present

Cumulative Landin g Distance Example ; and Table 3-3, All Factors Cumulative Landing

Distance Example Stabilized Approach and Timely Deceleration, provide guides to be considered in order to mitigate a runway ove rrun. Table 3-1 provides a memory jogger for the

concepts pilots must exercise to mitigate the risk of a runway overrun. Table 3-2 provides a

sample of what can occur if all the runway factors to consider are present in a landing. Table 3-3

demonstrates th e benefits of a stabilized approach, choosing to land with favorable winds, and

timely deceleration.

NOTE: These items cannot replace the information contained in the AFM.

They are provided to help the flightcrew member recognize the possible

increase in risk as sociated with certain conditions. The information

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Appendix 3

presented in this AC must not be used to replace or supplant AFM landing

performance or associated contaminated runway performance information provided by the manufacturer.

TABLE 3- 1. MEMORY JOGGER: CAN U S TOP?

CAN U STOP?

C–Calculate Use the manufacturer’s or company data to

determine the landing distance required prior to

departure and again prior to landing based on

company SOPs. Be sure to consider factors as

dry/wet runways and associated contamination ,

planned touchdown point, speed and height over

the landing threshold, runway slope,

tailwind/wind speed and direction, inoperative

equipment, and any special cases.

U–Understand The manufacturer’s AFM landing data and it is

derived based on flight test data. Factors to be

applied to the data to adjust it for the current

conditions. If data is not available, employ the

information contained in SAFO 06012.

S–Stabilized Ensure that you understand all the requirements of

a stabilized approach and you are ab le to fly one

given the actual conditions. If not, go around!

P-Professional Land like a professional using the airplane’s

capabilities as described in the AFM and SOPs.

A professional puts safety ahead of style.

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Appendix 3

TABLE 3- 2. ALL FACTORS PRESENT CUMULATIVE LANDING DISTANCE

EXAMPLE

1. Available runway length . 5,000 ft

2. Per AFM, Dry runway Un-factored AFM landing distance

for density altitude & lightest landing gross weight . 3,000 ft

3. Runway Slope -1%: Add 10% of landing distance per 1%

downhill slope, i.e., 1% downhill slope adds 10% to the

landing distance. 300 (3,300’)

4. Excessive airspeed at 50 foot landing threshold, l anding

distance increase: For each 10% increase in landing speed

greater than the AFM, add 20% landing distance or:

Example: 10 % f ast (3,300 × . 20 = 660 ft) . 660 ft (3,960’)

5. Tailwind Condition: Add 21% to landing distance for each

10 kts in tailwind .

Example : 10-kt Tailwind .21 × 3,960 = 832 ft . 832 ft (4,792’)

6. Extended Flare Add 200 ft per second flare time:

Results in a 2 00 ft/sec additive (2 × 200 = 400 ft). 400 ft (5,192’)

7. Excess 50 -ft height : Add 200 ft to the landing distance for

each 10 ft above 50 ft.

Example: 10 -ft excess . 200 ft (5,392’)

8. MEL/CDL additions : Any additions caused by minimum

equipment list (MEL)/Configuration Deviation List (CDL)

requirements No MEL /CDL additive 0 ft. 0

9. Sum of before landing items 2 through 8 added 2,392 f t =

80% greater than 3,000 ft . 5,392 ft

10. Deceleration devices , 3 second deployment t ime.

(1 second more than the 2 sec ond max) add 2 00 ft per each

second greater than 2 seconds.

Add 200 f t or use AFM data if available. 200 ft (5,592’)

11. Less than maximum braking add 20 % or use AFM data if

available. 1,118 ft (6,710’)

12. Wet Runway SAFO Safety Margin .

If wet, add 15 percent of line 9 or use AFM data if available

.15 × 5,392 = 809 ft. 1,107 ft (7,717’)

13. After landing factors, Lines 10 - 13 added 2, 425 ft, 45%

greater than 5,392 ft. Required landing distance 7,717 ft

2,717 ft longer than available.

Cumulative Landing Distance Increase: 157% 7,717 ft

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Appendix 3

TABLE 3- 3. ALL FACTORS CUMULATIVE LANDING DISTANCE EXAMPLE

STABILIZED APPROACH AND TIMELY DECELERATION

1. Available runway length. 5,000 ft

2. Per AFM, Dry runway Unfactored AFM landing distance

for density altitude & l ightest landing gross weight. 3,000 ft

3. Runway Slope -1%: Add 10 % of landing distance per 1 %

downhill slope, i.e., 1% downhill slope adds 10% to the

landing distance. 300

4. Excessive airspeed at 50 -ft landing threshold, landing

distance increase: For each 10% increase in landing speed

greater than the AFM, add 20% landing distance or:

Example: 10% fast (3,300 × .20 = 660 ft). 0

5. Tailwind Condition: Add 21% to landing distance for each

10 kts in tailwind.

Example: 10 kt Tailwind .21 × 3,960 = 832 ft . 0

6. Extended Flare Add 200 ft/sec flare time:

Results in a 200 ft/sec additive (2 × 200 = 400 ft). 0

7. Excess 50 -ft height – Add 200 ft to the landing distance for

each 10 ft above 50 ft. Example: 10 -ft excess. 0

8. MEL/CDL additions: Any additions caused by minimum

equipment list (MEL)/Configuration Deviation List (CDL)

requirements No MEL/CDL additive 0 ft. 0

9. Sum of before landin g items 2 through 8 added 2,392 ft

equals 80% greater than 3,000 ft. 3,300 ft

10. Deceleration device s, 3 second de ployment time.

(1 second more than the 2 second max) add 200 ft per each

second greater than 2 seconds.

Add 200 ft or use AFM data if available. 0

11. Less than maximum braking add 20% or use AFM data if

available. 0

12. Wet Runway SAFO Safety Margin.

If wet, add 15% of line 9 or use AFM data if available

.15 × 5,392 = 809 ft. 495 ft

13. After Landing factors Lines 10 - 13 added 495 ft, leaving

1,210 ft runway remaining after the 15% safety margin.

Reduced landing distance: 3,927 ft.

Cumulative landing d istance within 66% of available runway. 3,790 ft

NOTE: In a stabilized approach, the proficient pilot receives an accurate

runway condition report, chooses to land on a runway with a favorable wind

for landing, and adds a safety margin, which results in stoppin g within the

landing distance available .

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Appendix 4

APPENDIX 4. UNSTABILIZED APPROACH CASE STUDY

You, the first officer, obtained automated terminal information service (ATIS) information

during the descent that indicated strong westerly winds on the ground and field elevation of

approximately 800 feet (ft) mean sea level (MSL) . Because of terrain, the most common

approach to the landing runway is via the instrument landing system (ILS) approach to another runway, and then to perform a circle -to-land maneuver to the l anding runway.

(a) Air traffic control (ATC) then advises you of updates to the ATIS and also to

expect a straight -in approach. You have approximately 5 minutes to prepare for landing on the

new runway. Without performing a completely new approach briefing , you prepare for the

change in runway by confirming your previously planned flap setting of 40 degrees, with a

reference landing airspeed (V

REF) of 138 knots (kts). Given that the airplane is flying the ATC

assigned, heading and descending steadily with t he autopilot engaged, routine communications

with ATC almost entirely consume the short time available to prepare the approach.

(b) The newly assigned runway is relatively short and will have a tailwind; however,

the landing distance is adequate, but provi des little margin for error. While you are obtaining the

new ATIS (indicating a tailwind for landing, but within the airplane’s tailwind limit), the captain receives and acknowledges an ATC instruction to maintain 230 kts or more until advised, with vector s to a base leg, and to follow another airplane to intercept the final approach path. Then,

when ATC clears your airplane for a visual approach to the runway, the airplane is at 230 kts , at

5,000 ft MSL , and almost 10 miles away from the runway. Noting tha t the airport’s elevation is

approximately 800 ft MSL , the captain must both slow the airplane and descend relatively

quickly to make the landing, while configuring the airplane for landing.

(1) Do You Continue With the Approach? ATC positions the airplane hig h and fast

close to the runway, and now you face the difficult task of establishing a stabilized approach. Alternative options include either extending the approach path in cooperation with ATC or

abandoning the approach. However, 1 minute after ATC clears the airplane for the approach, you

perform the first configuration change to get the airplane below 225 kts (the maximum speed to extend flaps to 5 degrees). The airplan e is now descending to 3,000 ft , slowing through 225 kts,

and slightly overshooting the final approach course on autopilot.

(2) What Would Your Landing Strategy Be? The captain then disconnects the

autopilot and brings the airplane back on course, ordering gear extension and successive flap extensions, while maintaining 3,000 ft until 3 miles f rom the threshold. The captain then

commands flaps 40 while the airplane is above 180 kts. (Maximum speed for flaps 40 is well

below this speed.) The airplane then slows to 180 kts, and the captain is flying the approach at

more than twice the normal 3 -degree gradient to the runway in his or her efforts to touch down

just beyond the runway threshold. When the airplane passes below 1,200 ft above ground level (AGL), and its descent rate increases through 2,900 ft/minute, the ground proximity

warning system ( GPWS) “sink rate” warning starts to sound continuously, later followed by the

more stringent “whoop, whoop, pull up” warning.

(3) What is Your Reaction? When the airplane reaches 1,000 ft above airport elevation,

its airspeed has increased to almost 200 kts wi th a 14-knot tailwind, and it is descending at more

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Appendix 4

than 2,600 ft/minute. When descending through 500 ft, 16 seconds from touchdown, speed is

unchanged and descent rate is almost 2,000 ft/minute. You miss the 500 ft required callout as you are also concern ed about the airplane that has landed ahead and has not yet cleared the

runway. Despite all of this, the airplane continues at a steep gradient greater than 3 degrees until the captain begins the flare for landing at approximately 150 ft AGL. Although he m anages to

land the airplane within the normal TDZ, he has not been able to slow the airplane while descending at that angle. Despite the engines remaining at idle, the airplane is flying on average some 45 kts faster than the target speed throughout the fi nal approach and landing. The airplane

touches down at a speed of 182 kts, with a 6- knot tailwind, some 2,150 ft beyond the runway

threshold with approximately 3,900 ft of runway remaining. The captain does not apply and hold maximum brake pressure (as it was the airline’s policy to use manual braking rather than autobraking during landing rollouts), and uses reverse thrust. However, he is unable to stop the airplane on the runway, and the airplane overruns the runway.

(4) Lesson Learned. The lesson learned is that flying a stabilized approach is critical for

safety, regardless of whether one is flying an airliner or a light airplane. Always fly per company procedures, use the manufacturer’s AFM/POH landing performance for the current landing conditions, exercis e sound aeronautical decision -making (ADM) , and ensure the following:

(a) The airplan e is on the correct flight path.

(b) Only small changes in heading/pitch are necessary to m aintain the correct

flight path.

(c) For large airplanes, the airspeed is not faster than V

REF (threshold crossing speed)

plus 5 kts indicated speed, or as stated in the SOP for windy conditions. Do not fly slower than

VREF. For small airplanes, after aligning with the runway, fly the AFM/POH recommended

approach airspeed, and adjust airspeed for windy conditions. In the absence of a manufacturer’s

recommended approach airspeed, use 1.3×V SO (stall speed or minimum stead flight speed at

which the airplane is controllable in the landing configuration), and use flaps per the wind

conditions, or as re commended by the manufacturer to ensure positive lateral airplane control

during the flare to t ouch down. (Refer to the current edition of FAA -H-8083- 3, Airplane Flying

Handbook, for more information.)

(d) The airplane is in th e correct landing configuration.

(e) Power setting is appropriate for the airplane configuration and is not below the

minimum power for the approach as defined by the operating manual; and the crew has conducted all briefings and checklists.

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