Boeing Perf Cse V1 Go-No Go

FLIGHTOPERATIONS

ENGINEERING

1For Training Purposes Only © Copyright 2009 Boeing All Rights Reserved

V1 Go-No Go

Performance Engineer Operations

Bruce LindstromFlight Operations Engineering

Boeing Commercial AirplanesSeptember 2009


RTO-R

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ED

ACCI

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CONT

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!

DAILY NEWSNEW YORK’S PICTURE NEWSPAPER35 cents Friday, September 22, 1989


Objectives

• Stress the importance of V1

• Learn from Statistics of past Rejected Takeoff (RTO) accidents and incidents

• Educate for a better “Go/No Go” decision

• Avoid future overruns and RTO’s!


Reasons for RTOs?

NTSB post accident/incident discoveries

• Rejects were unnecessary

• V1 technique improper

The NTSB concluded:“…Pilots faced with unusual or unique situations

may perform high-speed RTO’s unnecessarily or may perform them improperly.”

February 1990


The “Human Factor Approach”

Takeoff Safety


Takeoff Safety Training Aid Development1990 - 1992

Draft review mailing grew to 137

• 35 airlines (12 U.S.)

• 3 pilot associations

• 7 government agencies

• 5 industry associations

• 10 manufacturers


Takeoff Safety Training Aid Contents

Section 1 Overview for Management

Section 2 Pilot Guide to Takeoff Safety

Section 3 Example Takeoff Safety Training Program

Section 4 Takeoff Safety - Background Data

Video “Rejected Takeoff and the ‘Go/No-Go’ Decision”

Flexibility to incorporate lessons into your initial, transition, and recurrent training programs to meet your needs.


Objectives of Takeoff SafetyTraining Aid

• Benefit from Lessons Learned– Past Accidents– RTO Safety Task Force– Pilot Performance Study

• Improve ability of pilots to take maximum advantage of all takeoff performance margins

• Make best “Go/No-Go” decisions

• Effectively accomplish related procedure


97 RTO Overrun Accidents/IncidentsSince 1959

74 overruns included in original NTSB study23 overruns since NTSB study


Takeoffs, RTOs, and Overruns

Takeoffs

RTOs (estimate)

RTO Overrun Accidents/Incidents

Through 2003

430,000,000

143,000

97

18,000,000

6,000

4

Typical Recent Year


Takeoffs and RTO Overrun Incidents/Accidents ( By Decade )

Rate per 10 million takeoffsRTO overrun accidents/incidents per 10 million takeoffs

Decade Departures RTO overrun accidents/incidents

1960 - 19691970 - 19791980 - 19891990 - 1999

19,045,36375,984,954108,963,013161,957,587

12322822

6.34.22.61.4

1960’s 1970’s 1980’s 1990’s020

4060

80100

120140

160180

Millions of takeoffs

0

1

2

3

4

5

6

7

Rate per10 million takeoffs

6.3

4.2

1.4

2.6

109

162

19

76


Total Industry RTO’s

80 knots or less

Percent of total

80

60

40

20

0

76%

80 to 100 knots

100 to 120 knots

Above 120 knots

18%

4%2%

RTO overrun accidentsprincipally come from the 2% of the RTO'sthat are high speed

As a Function of Speed


RTO Accidents/Incidents - 97 Events

Unknown21%

Greater than V1

55%Less than/equal to V1

25%

Initiation Speed


RTO Accidents/Incidents - 97 Events

Not reported30%

Dry38%

Snow8% Wet

24%

Runway Condition


Engine

Wheel/tire

Configuration

Indicator/light

Crew coordination

Bird strike

ATC

Other/not reported

21%

22%

0 5 10 15 20

Percent of total (97 events)

12%

14%

10%

7%

11%

2%

Reasons for Initiating RTO – 97 Events

Non-Engine*79%

Engine21%

*Including events “Not reported”

David

Highlight


Review of the 97 Events Revealed:

By continuing the takeoff

52%

Unavoidable18%

By correct stop techniques15%

By better preflight planning15%

82% were avoidable

David

Highlight


What Do The Statistics Mean?

• RTOs are not common

• Infrequency leads to complacency

• Pilot must be prepared


Key Subjects for Flight Crews

• Regulatory Rules and Certification Criteria

• Takeoff Performance

• Effects of Airplane and System Configuration

• Takeoff Safety Margins


Decision Time?

“Oops, I think I should have already made my decision”


V1 Misnomer and Definition

V1 is interpreted differently:– Pilots– Engineers– Regulatory Agencies

V1 - is the speed at which the takeoff should be continued unless the stopping maneuver has already been initiated.

David

Highlight


V1 Is Two Concepts

V1 - Stop( Maximum “STOP” Speed )

V1 - Go( Minimum “GO” Speed ) 35 ft


Historical FAR V1 Definition :

(Prior to March 1, 1978)

[FAR Paragraph 25.107(a)]

V1 – Critical engine failure speed.“V1 is the critical engine failure speed. It shall not

be less than the minimum speed at which controllability by aerodynamic controls alone is demonstrated during the takeoff run to be adequate to permit proceeding safely with the takeoff using average pilot skill, when the critical engine is suddenly made inoperative.”


Historical FAR V1 Definition :

(March 1, 1978)

[FAR Paragraph 25.107(a)(2)]

V1 – Takeoff decision speed.

“It cannot be less than VEF plus the speed gained with the critical engine inoperative during the time interval between the instant the critical engine has failed and the instant the pilot has recognized and reacted to the engine failure by application of the first retarding means.”


Current FAR V1 Definition :

(March 20, 1998)

[FAR Paragraph 25.107(a)(2)]

V1 – No longer described as “Takeoff decision speed”

“It cannot be less than VEF plus the speed gained with the critical engine inoperative during the time interval between the instant the critical engine has failed and the instant the pilot has recognized and reacted to the engine failure, as indicated by the pilot’s initiation of the first action to stop the airplane.”


Takeoff Rules

All enginesGo Distance

V1

VR VLOF

• 35 feet

• V2 + 10 to 25 knots*

*(Varies with airplane type)

FAR Takeoff Field Length (Case #1)

+15%

Actual distance * 1.15


Takeoff Rules

V1

1 sec

One engine inoperativeAccelerate-Go Distance VEF VR VLOF

• 35 feet

• V2



One engine inoperative/ all-engine

Accelerate-Stop DistanceV

event

Takeoff Rules


RTO transition complete

Transition

V1

1 sec

Stop


Takeoff Rules

FAR Takeoff Field Length

RTO transition complete

One engine inoperative/ all engineAccelerate-Stop Distance

V1

VEVENT

TransitionStop

1 sec

• 35 feet

• V2 + 10 to 25 knots*

*(Varies with airplane type)

All enginesGo Distance (115% actual)

1.15 times the actual distance

• 35 feet

• V2

One engine inoperativeAccelerate-Go Distance

V1

VEF VR VLOF

1 sec


Transition to Stopping Configuration

DecisionV1

Speedbrakes raisedBrakes applied

Thrust levers to

idle

Distance allowance


Service allowance

Rejected Takeoff Sequence

CertificationFlight Test

Full braking configuration

AFMExpansion

AFM expansion approximately 4 seconds

Full braking configuration

TimeF/T Demo 2.0 seconds

Speedbrakesup

Throttles to idle

Flt Test demonstrated transition1 to 1.4 seconds

Enginefailure

Recognition( min 1 second)

V1

Brakes onDry runway performance in AFM does not include thrust reverser credit…


Model Specific Transition Times


Accelerate-Stop Transition Distance

“Pre 1981”707, 727, 737-100/200747-100/200/SP/300DC-8, DC-9, DC-10MD-80

“Post 1981”757, 767, 747-400737-300/400/500

Amendment 25-42777-200/300 (1995)MD-11, MD-90

Acceleration Transition

1sec

3 sec(typical)

Brakes Throttle

2 seccontinued

accelerationFlt test

transition

Flt testtransition

VEF

VEF

VEVENT

V1

2 secat VB

Amendment 25-92737 NG, 757-300767-400 (1998), 717

2 secat V1 Flt test

transitionVEVENT

Typically100 -150 ft

longer

Stopping

Speed brakes

Typically60 – 100 ft

shorter

Typically130 – 400 ft

shorter

Baseline


Takeoff Safety Training Aid Video


Maximum Allowable Takeoff Weight

Lowest of all the weight limitations• Performance (Varies from day-to-day)

– Runway• Field Length• Tire Speed• Brake Energy• Obstacle

– Climb

• Structural (AFM Restriction – Maximum Certified)

• Other– Noise– Runway Loading– Landing at destination– Enroute Requirements


115% all-engine

Effect of V1 Speed on Takeoff Weight (for a fixed runway length)

Airplaneweight

V1 speed

Incr

easi

ng

Increasing

Continued takeoff

Rejectedtakeoff

Field limit weight

Bala

nced

fiel

dV

1 sp

eed

Climb Limit


Balanced Field

Engine-out go distance = Accelerate-stop distanceEngine-out go distance = Accelerate-stop distance

But the actual runway available is usually longer than the minimum Balanced Field Length Required


Details of the “Go” versus “Stop” Decision

Runway used to accelerate to V1 (typically 60%)

Runway available to Go/Stop (typically

40%)

One engine inoperativeAccelerate-Go Distance

V1

VEF

1 second minimum

• 35 feet

• V2

VR VLOF

1 second minimum

V1

VEVENT

Accelerate-Stop Distance

Stop

RTO transition complete (AFM)

Transition


15 degree bank turn will reduce these climb rates by approximately 100 FPM

2 engine

3 engine

4 engine

Minimum gradient required

3%

2.7%

2.4%

Typical rate of climb

520 FPM at V2~170 knots



Climb Gradients


Runway Surface ConditionWet or Contaminated

Affects friction between runway and tires


Dynamic Hydroplaning

• Tire Braking Virtually Eliminated

• Highly Sensitive to Speed

Flooded runway

Must Apply Steady Brake Pressure!


Maximum Stopping Performance

• Max brakes

• Thrust idle

• Speedbrakes

• Reverse thrust


Heat Buildup

Long taxi

Excessive braking

Tires and Brakes

Wheel cracks

Foreign objects

Visual Inspection


Residual Brake Energy

• Observe BrakeTemperature Limitationsand/or Minimum CoolingTimes

• Follow Maximum QuickTurnaround Weight(MQTW) Chart


• Same initial conditionsTire fails

V1

• Landing flaps• Certified performance less

blown tire effects• Takeoff weight minus burnoff

and fuel dump (opt)50 ft

40 to 60% StopZone

Reject

Margin 60 to 40 %Available Runway

• Takeoff flaps• Certified performance• Dry runway• Field length limit weight

V1VEF

Engine fails

VR35 ftGo

Reject

Transition complete

Full stoppingno reverse

GoVR

Approx 150 ft

Transition complete

Reduced brakingcapability plus all engine reverse

40 to60 kts

300 to 500 ft overrun

Go and Stop Margins with a Tire Failure


400- to 600-feet overrun

60-70 kts

Speedbrakes

Stopping with airplane brakes but no speedbrakes


Speedbrake Effects

Speed-brakes down Lift

Load on wheels

DragBrakes

Speed-brakes up

34% increase

Total stopping force capability

BrakesDrag

Forward motion

Rolling

Weight on tire

Brake torque

Braking force

(Braking force = braking friction x load on tire)*

* Brake torque not limiting

Down Up

Speedbrake position Difference speedbrake up

DragLiftNet load on wheelsMaximum braking forceMaximum stopping force(brakes and drag)

8,500 lbs52,000 lbs

141,60075,500

84,400

14,700 lbs-1,200

194,80098,000

112,700

+73%-102%+38%+29%

+34%


Speedbrakes Versus Reverse Thrust

Field length limit dry runway

One engine-out RTO

Brakes + speedbrakes + reverse thrust

One engine-out RTO

Brakes + reverse thrust

300- to 600-ft overrun

100- to 300-ft margin


Minimum Equipment List (MEL) and Configuration Deviation List (CDL)

• May affect ability to accelerate/decelerate

** Check Revised Procedures **


0

Speed off end of runway, knots

Abort initiation speed above scheduled V1, knots

4 8 12

120

80

40

0

One second delay

Maximum effort stop

Takeoff “Stop” Margins

Shaded area indicates degraded stopping performance• Contaminated runway• Pilot technique• System failures


One second early

Height at end of runway (feet)

Speed relative to V1 (knots)

0

10

20

30(35)

40

(150)

One engine inoperative

All engines

-20 -16 -12 -8 -4 0 +4 +8

V2 + 10 to 25 knots

V2

4 engine airplane

3 engine airplane

2 engine airplane

Takeoff “Go” Margins


TAKEOFF REF f / f O A T V 1

2 3 º C 130 K TSEL TEMP V R

- - - º C 131 K TSEL TEMP V 292 . 5 / 9 2 . 5 % 139 K T- - - - - - - P R E - F L T C O M P L E T E - - - - - - -

- - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -> I N D E X

FMS Speeds and Weights

• NO Safety Margin Data Available


Flap Selection Typical Large Two-engine Airplane Takeoff Performance

Flap setting8,700ft. runway sea level 37° C

1 5 15 20

Runway limit weight, lb. (kg)

358,300(162,494)

374,200(169,705)

389,000(176,417)

393,600(178,503)

Climb/obstaclelimit weight, lb. (kg)

414,100(187,800)

407,300(184,717)

393,600(178,503)

383,000(173,696)


RTO Safety Task Force Recommendations

• Develop “model”training practices

• Develop “model”operational guidelines

• Improve simulator fidelity• Provide runway

condition reports• Residual brake heat

accountability

AdvisoryRegulatory• Standardize accelerate-

stop transition• Wet runway accountability• Worn brake accountability• Line up distance

accountability


Better Simulator Fidelity

Validates Desired Performance


Operations and Training Recommendations

Pilots need more education and training on:Training: Ground• Meaning of V1

• Basic performance• Contaminants• Reverse thrust• Flap selection

and reduced V1

Operational• High speed callout• Timely V1 callout• Correct procedures• Standardize callout• Use of RTO

autobrakes• Pre-takeoff briefing

Training: Simulator• Maximum braking

techniques• RTO on balanced

field• Tire failures• Warnings/cautions


The Crew

• Preflight briefing

• Cockpit callouts

• Positive action if malfunction occurs


The Briefing

• Clear

• Concise

Agreement of Responsibilities( MEL, weather, noise abatement, etc.)


Use Standard Callouts(Normal, malfunctions, V1)

Communication

• Precise

• Clear


Timely V1 Callout

Finish the callout as the airplane reaches V1

600

80100

120

140160

180200

400350

300

250240

220

KNOTS

MACH

1 2 67

5

Ensures a “No Go”decision will not bemade after V1


Items to Reject For

Low speed:

• System failures

• Unusual noise or vibration

• Tire failures

• Abnormal acceleration

• Fire or fire warning

• Engine failure

• Unsafe takeoff configuration

• Unsafe or unable to fly

High speed:•Engine failure or fire•Unsafe or unable to fly

The FCOM RTO procedure may list other items to reject for in the high speed regime:

• Predictive Windshear Warning• Fire or Fire Warning


FSAT 96-05 - Operator Use of "Takeoff Training Aid"

{New-96-6 Added June 30, 1996}Flight Standards Information Bulletin (FSIB) for Air Transportation (FSAT)EFFECTIVE DATE: 05-08-96TRACKING: NTSB Recommendations A-90-41 through -48NOTE: THIS BULLETIN REQUIRES PTRS INPUT. SEE ITEM 3.

1. BACKGROUND. National Tran sportation Safety Board (NTSB) Safety Recommendations A-90-41 through -48 address Federal Aviation Administration (FAA) oversight of airline pilot training in rejected takeoff (RTO) maneuvers.The FAA published Advisory Circular (AC) 120-62, "Takeoff Training Aid," which responds to these recommendations. The Safety Board is concerned that some operators are not using the material contained in the AC in their training and procedures. To reassure the NTSB that the AC has been implemented by all Title 14 Code of Federal Regulations part 121 (14 CFR part 121) operators, the FAA is documenting the material's implementation and use by all operators in pilot training programs and operations.

2. ACTION. Principal operations inspectors (POI) are requested to document that all operators are using the information contained in AC 120-62 in both training and procedures. This documentation is requested within sixty (60) working days of the effective date of this bulletin.

3. PROGRAM TRACKING AND REPORTING SUBSYSTEM (PTRS). POI’sshall make a PTRS entry to document that each operator is using the information in AC 120-62 in both training and procedures. POI's shall follow the procedures as outlined in HBAT 94-08, Program Tracking and Reporting Subsystem (PTRS) Documentation of Action Required by Flight Standards Bulletins. The PTRS entry shall be listed as Activity Code Number 1381; the "national use" field entry should be “FSAT9605.” POI's should use the comments' section to record comments of interaction with the operators

4. INQUIRIES. Questions or comments regarding this FSAT should be directed to AFS-210 at (202) 267-7480.

5. EXPIRATION DATE. This FSAT will expire May 31, 1997.

/s/David R. Harrington

Advisory Circular 120-62

To reassure the NTSB that the AC has been implemented by all Title 14 Code of Federal Regulations part 121 (14 CFR part 121) operators,

Principal operations inspectors (POI) are requested to document that all operators are using the information contained in AC 120-62 in both training and procedures.


Final Thoughts

• 82% of events were avoidable

• Full thrust available in 79% of cases

• Over half of rejects were initiated after V1

• Many takeoffs performed at less than limiting weight

• More margins exist with “Go” decision

David

Highlight

Boeing Perf Cse V1 Go-No Go

Documents

Transcript of Boeing Perf Cse V1 Go-No Go