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GENERIC STALL (FBW) 0/23
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GENERIC STALL (FBW) 1/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 2/23
Introduction
Accidents following failure to recover from stall still occur
Stalls are frequently performed in flight test by all aircraft manufacturer for development and certification:
Unique experience to be shared with operational community
Objective of this presentation: to make the operational community aware of the need to change the current methods
of STALL or APPROACH TO STALL recovery techniques
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GENERIC STALL (FBW) 3/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 4/23
Aerodynamic Review
Lift = .S.V.Cl: air densityS : wing surfaceV : CASCl : lift coefficient
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GENERIC STALL (FBW) 5/23
Lift Coefficient
For a given configuration, a given speed and a given altitude,
The Lift is only linked to AoA
Cl has a direct relationship to AoA
Cl
AOA(Angle o Attack)
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GENERIC STALL (FBW) 6/23
Stall
At a given AoA, the air flow separates from the profile, the Cl drops The wing profile is stalled
For a given aircraft configuration and speed,
An aircraft stalls for a given AoA
Cl has a direct relationship to AoA
1
3
2
1
2
3
Cl
AOA(Angle o Attack)
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GENERIC STALL (FBW) 7/23
Stall
Stall is an AoA problem onlyFor a given load factor, the loss of speed leads to increase the AoA, which could reach the stall AoA
Stall is an AoA problem only
It is NOT directly a speed issue
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GENERIC STALL (FBW) 8/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 9/23
AoA Control
RelativeAirflow
The pitch control is a direct AoA command
The elevators control DIRECTLY the AoA
A nose down command has an IMMEDIATE effect: an AoA decrease
AoA
CG
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GENERIC STALL (FBW) 10/23
AoA Control
The pitch control is a direct AoA command
The elevators control DIRECTLY the AoA
A nose down command has an IMMEDIATE effect: an AoA decrease
AoA
RelativeAirflow
AoA
CG
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GENERIC STALL (FBW) 11/23
AoA Control
Aircraft with engine below aircraft CG Thrust has a significant pitch effect
AoAAoA
RelativeAirflow
AoA
CG
Thrust Increase
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GENERIC STALL (FBW) 12/23
AoA Control
Aircraft with engine below aircraft CG Thrust has a significant pitch effect
Thrust increase AoA increase
RelativeAirflow
AoA
CG
Thrust Increase
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GENERIC STALL (FBW) 13/23
AoA Control
Aircraft with engine below aircraft CG Thrust has a significant pitch effect
RelativeAirflow
AoA
CG
Thrust Reduction
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GENERIC STALL (FBW) 14/23
AoA Control
Aircraft with engine below aircraft CG Thrust has a significant pitch effect
Thrust reduction AoA decrease
AoAAoA
RelativeAirflow
AoA
CG
Thrust Reduction
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GENERIC STALL (FBW) 15/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 16/23
Stall vs. Approach To Stall
The traditional APPROACH TO STALL training is characterized by a controlled deceleration to stall warning, followed by a power recovery with minimum altitude loss
The difference between an APPROACHING STALL and an ACTUAL STALL is not easy to determine, even for specialists
In numerous accidents, the APPROACH TO STALL procedure was applied whereas the aircraft was actually stalled
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GENERIC STALL (FBW) 17/23
Approach To Stall Recovery
A single procedure has to be defined focusing on AoA reduction
Classical Approach to stall procedure focuses:On thrust application
Minimum loss of altitude
It is NOT appropriate for EVERY stall condition:Possible inability to reduce AoA with the TOGA thrust application
Recovery may require thrust reduction
Recovery from a stall may require altitude loss
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GENERIC STALL (FBW) 18/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 19/23
Stall Recovery
As soon as any stall indication is recognized
NOSE DOWN PITCH CONTROLAPPLY:AoA must be reduced to regain lift: Apply nose down pitch order on the side-stick If needed, reduce thrust in case of lack of pitch down authority Ensure wings are level
AoA comes first
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GENERIC STALL (FBW) 20/23
Stall Recovery
When out of stall
INCREASE ENERGYThrust increase smoothly as needed
Notes: . Immediate maximum thrust application upon stall recognition is not appropriate
. Thrust has an adverse effect on AoA for aircraft with under wing mounted engines
. Due to the engine spool up time, the aircraft speed increase that results from thrust increase,
is slow and does not enable to reduce the AOA instantaneously
Ensure that speed brakes are retracted
Recover smoothly the initial flight path
AoA comes first, energy second
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GENERIC STALL (FBW) 21/23
Content
Introduction
Stall phenomenon
AoA control
Stall vs. Approach to stall
Stall recovery
Way forward: New procedure
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GENERIC STALL (FBW) 22/23
New Procedure
Spirit of what is the new procedureOne single procedure to cover ALL stall conditions
Get rid of TOGA as first action
Focus on AoA reduction
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GENERIC STALL (FBW) 23/23
New Procedure The stall recovery procedure is available on the Airbus
World portal and will be dispatched to operators as follows:A318/319/320/321 aircraft:
FCOM volume 3 Temporary Revision number 323-1 QRH Temporary Revision number 727-1
A330 aircraft: FCOM volume 3 Temporary Revision number 552-1 QRH Temporary Revision number 353-1
A340 aircraft: FCOM volume 3 Temporary Revision number 512-1 (A340-200/-300) FCOM volume 3 Temporary Revision number 513-1 (A340-500/-600) QRH Temporary Revision number 369-1
A380 aircraft: FCOM Procedures / Non-ECAM Abnormal and Emergency Procedures /
Operating Techniques
In addition, the Flight Crew Training Manuals will be revised accordingly
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AIRBUS S.A.S. All rights reserved. Confidential andproprietary document.
This document and all information contained herein is thesole property of AIRBUS S.A.S.. No intellectual propertyrights are granted by the delivery of this document or thedisclosure of its content. This document shall not bereproduced or disclosed to a third party without the expresswritten consent of AIRBUS S.A.S. This document and itscontent shall not be used for any purpose other than that forwhich it is supplied.
The statements made herein do not constitute an offer.They are based on the mentioned assumptions and areexpressed in good faith. Where the supporting grounds forthese statements are not shown, AIRBUS S.A.S. will bepleased to explain the basis thereof.
AIRBUS, its logo, A300, A310, A318, A319, A320, A321,A330, A340, A350, A380, A400M are registeredtrademarks.
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GENERIC STALL (FBW) 25/23
Stall
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