18_RTO

(1)

Revisiting the Stop or Go decision

Rejecting Takeoff Procedure & Training

Presented by

Peimann TOFIGHI-NIAKI

A300/A310 Family

Flight Operations Engineer

Flight Operations Safety Enhancement

(2)

Flight Operations Safety Awareness Seminar Moscow 2009 – Revisiting the Stop or Go decision Slide 2

Content



Background



Operational Standards



Factors involved in the decision-making



Prevention Strategies

(3)

Background



Improvement of the rate of RTO overrun accidents/incidents:

Implementation of policies,

training practices and

operational guidelines

developed by the Industry

(4)

Background



Split between high speed and low speed RTO

8% High Speed

(>100 kt)

92% Low Speed

(<100 kt)

Source: IATA Steades 2002

Potential runway

overrun

(5)

Background



Analysis of 94 RTO overrun accidents/incidents 1961 to 1999

revealed that more than half of RTO overrun

accidents/incidents occurred at speeds greater than V1:

Greater

than V1

54%

Less than or

equal to V1

26%

Unknown

20%

Importance of making the STOP or GO decision

prior to reaching V1 and of a timely V1 callout

(6)

Background



Experience has shown that rejected takeoffs at higher

speeds, on a balanced field runway (i.e. accel/stop distance

at V1 equals runway lenght), can be hazardous even if the

performance is correctly calculated

WHY?

Factors that may detract from

a successful RTO …

(7)

Background



Error in aircraft TOW determination (loadsheet…)



Error in T/O data calculation (V1, VR, V2, FLEX TEMP…)



_{Tire damage}



Brake worn or not working properly



Too high residual brake temperature



Incorrect runway line-up technique



Delay in initiating the stop action during T/O roll if failure



Runway friction coefficient lower than expected

Factors that may detract from

a successful RTO …

(8)

Background

Performance

Training

(9)

Content



Background



Operational Standards



Factors involved in the decision-making



Prevention Strategies

(10)

Operational Standards - Decision



STOP

or

GO

=

Captain’s decision



Below 100 kt

–

Any indication of system malfunction should result in a

STOP

decision

Airspeed

₀

₈₀

₁₀₀

Low

Speed

STOP

or GO

• Split into

low

and

high

speed regime:

100 kt

THRUST

SET

100

(11)

Airspeed

₀

₈₀

₁₀₀

Low

Speed

STOP

or GO

… STOP

or

GO …

Operational Standards - Decision



Engine or APU fire warning



Sudden loss of thrust



ECAM alerts (refer to FCOM)



Indications that the aircraft will

not fly safely

STOP



Nose gear vibrations

GO



“Bang” without thrust loss



Open sliding windows



EGT over limit



Above 100 kt

–

Be “

go-minded

” and do not delay the decision

–

Only major failures may justify a

STOP

decision

Airspeed

_V

1

80

100

0 Low

Speed

High

Speed

STOP

or GO

… STOP

or

GO …

STOP or

GO

…

STOP

…

(12)

Airspeed

_V

1

80

100

0 Low

Speed

High

Speed

STOP

or GO

… STOP

or

GO …

STOP or

GO

…

STOP

…

Operational Standards - Decision



At V1

–

Takeoff must be continued

–

No action below 400 ft

A height of 400 ft is recommended as a good compromise between the time

required to stabilize the flight path and the acceptable delay to initiate the

procedure associated to the failure.

–

CAPT must remove his hand from the Thrust Levers



Above V1

Airspeed

_V

1

80

100

0 Low

Speed

High

Speed

STOP

or GO

… STOP

or

GO …

STOP or

GO

…

STOP

…

Airspeed

GO

V

₁

V

_R

V

₂

80

100

0 Low

Speed

High

Speed

STOP

or GO

… STOP

or

GO …

STOP or

GO

…

STOP

…

V1

PNF callout

(13)

Operational Standards - Stopping procedure

(14)

Operational Standards - Stopping procedure

1 CAPT

F/O

"

DECEL

"

Calls . . . . "

REVERSE GREEN

"

1

2 Calls . . . "

STOP

"

Trust levers . . . IDLE

Reverse thrust . . . MAX AVAIL

1 

Review of the procedure

“

DECEL

”:

the deceleration is felt by the crew, and

confirmed by the speed trend on PFD.

It can also be confirmed by DECEL light

A320/A330/A340

ex: A320

ATS . . . DISCONNECT

A300 Family

1

2

(15)

Operational Standards - Stopping procedure

CAPT

F/O

"

DECEL

"

70 kts

" ("80 kts"

for A300 Family

)

Calls . . . . "

REVERSE GREEN

"

1

2 Calls . . . "

STOP

"

Trust levers . . . IDLE

Reverse thrust . . . MAX AVAIL

Cancels any audio warning

1 Reverse thrust . . . . STOWED

Parking brake . . . APPLY

PA call . . "

ATTENTION CREW

AT STATION

"

Calls for . . . . "

ECAM ACTION

"

Advises ATC

Locates EMERGENCY

EVACUATION C/L

Completes ECAM ACTIONS

2

3

4

3 Aircraft stopped



Review of the procedure

ex: A320

AUTO BRK does not activate below:



72 kts (GS) for A320-A330-A340



80 kts (GS) for A300 Family

3

1

4

2

3

2

(16)

Content



Background



Operational Standards



Factors involved in the decision-making



Prevention Strategies

(17)

Factors Involved in the Decision Making



Unexpected conditions during takeoff roll:

– Atmospheric conditions

– Indicated airspeed discrepancy at 100 kts or before

– Aircraft tendency to pitch up

– Loss or difficulty to maintain lateral control

– Malfunction of engine system

– Unusual noise and/or vibration (e.g.: nose gear vibration, tire burst, engine stall,

suspected bomb explosion …)

– System failure(s) triggering ECAM warnings/cautions and/or cockpit

indications

– Broken crew-seat latch

– Bird strike

– Traffic conflict / Runway Incursion (particularly on congested airports)

– Open windows, doors

– Any type of indication that the aircraft is unsafe or unable to fly

– Lack of proper communication between flight crew (e.g.: untimely power check,

speed callout, …)

(18)

Factors Involved in the Decision Making



Stop

or

go

?



Severity of the malfunction



Aircraft speed



Atmospheric conditions



Runway characteristics and condition



Dispatch under MEL

(19)

Factors Involved in the Decision Making



Performance of the decision-making is affected by:



Limited decision-making time



Recognition time of unexpected conditions (i.e. unusual or

unique situations)



Lack of understanding of cues associated to problems which

may occur during takeoff roll



Non-adherence to published callouts (e.g. 80kts thrust set,

100 kts, V1…)



Crew coordination



Complacency

(20)

Content



Background



Operational Standards



Factors involved in the decision-making



Prevention Strategies

(21)

Prevention Strategies



Objective:



When an event occurs during the takeoff roll, the crew’s reaction

must be automatic (“instinctive”) and correct

– Airline’s policy and procedures

• Captain’s decisions, low/high speed philosophy, standard

callouts, task-sharing, SOP, who has the authority to reject…

– Education and Training

(22)

Prevention Strategies



Standard callouts: Develop the proper stop or go mindset:

Airspeeds

low speed / high speed

STOP

or GO … STOP

or

GO … STOP or

GO

…

STOP

…

GO

V

₁

V

_R

V

₂

80

100

0 High

speed

regime!

Timely V1

callout

Power set …

(23)

Prevention Strategies



Standard Operating Procedures:



Pre-flight preparation

– Takeoff data (high weight, high V1, …), aircraft’s technical status (MEL item,

…), runway conditions, bird activity, windshear …



Exterior inspection

– Tire conditions, brake wear…



Takeoff briefing:

– Includes all essential data associated to the T/O with

present conditions

• P/F and PNF role during take off roll

– Includes an

”abnormal condition” briefing

• Captain’s decision in case of malfunction – STOP or GO -, PF/PNF

respective role in case of GO decision, and Captain/F/O respective role

in case of STOP decision



Line-up technique

Each takeoff

is unique!

(24)

Prevention Strategies



Education and Training:

Example of

takeoff safety

training program

(25)

Prevention Strategies



Education and Training:



Ground training

– Meaning of V1, understanding of reasons for RTO, technical

understanding of takeoff performance, contaminants, reverse thrust,

flap selection and reduced V1, influence of line-up techniques,

power setting technique, …



Simulator sessions

– Handling of engine failure

– Simulator excercises, when practicable, where the crew have to

recognize situations that are not the result of a clear and distinct

loss of thrust:

• Engine stall accompanied with loud bang (without loss of thrust)

• Tire burst

• Traffic conflicts (“Abort”)

(26)

Prevention Strategies



Education and Training:



Simulator sessions (cont’d)

– Maximum braking techniques, RTO on balanced field, tire failures,

warnings/cautions that may be triggered at high speeds, timely V1 callout, …



Items to be discussed and reviewed during recurrent

training:

– Engine failure very close to V1: what are the consequences in case of a go

decision? …

– Advantage of a go decision and immediate return, but also potential

problems …

– Nose gear vibration, opening sliding windows should not lead to a stop

decision above 100 kt

– Tire burst within the 20kts range from V1: stop or go? …

– Birdstrike at high speed …

(27)

Conclusion



Develop

airline’s policy to define:



Who makes the decision to stop or go (i.e.

Captain’s decision

)?



When is a stop decision recommended pending upon the speed regime and the

nature & severity of the malfunction?



What are the actions in case of stop or go decision during the takeoff roll and

the respective task-sharing?



Enhance the stop or go decision mindset and task-sharing, during the

takeoff briefing based on the present conditions and on potential

abnormal situations



Practice during training, and/or review the conditions that may validate a

stop or go decision



Educate a proper understanding of the aircraft’s stop or go

performance, and outline proper operational interpretation of V1 (i.e. V1

(28)

FOBN:

Revisiting the Stop or Go

Decision