Enhanced Stall Recovery Procedure_Philip Adrian

WARNING: The technology herein is controlled by U.S. Export Administration Regulations. Any export or re-export of this technology must comply with the EAR.

Controlled by ECCN: 9E991 Date: 09-01-11

Copyright © 2011 Boeing. All rights reserved.

Enhanced Stall Recovery Procedure

Captain Philip AdrianChief Pilot Regulatory Affairs737 Chief Technical PilotThe Boeing Company


Enhanced Stall Recovery

Goal

To reduce the number of worldwide stall-related transport accidents



Obstacles and Causes to meeting the goal

•Flight crews may not recognize stall situation

– Limited training exposure to stall recovery– Limited actual stall experience, simulator envelope validation– Precursors are often varied

•Flight crews may react inappropriately to stick shaker (SS) onset

– Some flight crews pull column aft at stick shaker (SS) onset– Some flight crews are unfamiliar with SS or its implications

Past training: minimize altitude loss



FAA/Industry Working Group Deliverables

• Stall Recovery Template– ATR, Airbus, Boeing, Bombardier, Embraer

• Training– FAA Working Group– Boeing FOTB and FCTM Updates

• Simulators– Adequate to accomplish Approach to Stall– Recommend checks and improvements

• FAA Practical Test Standards (PTS)– First indication of an impending stall (added aural

and/or visual warnings)– It is expected that some loss of altitude will occur

during recovery



Preliminary enhanced stall recovery emphasis changes:

Stall Recovery Considerations Traditional Procedures Delivered Procedures

Disconnect autothrottle/autopilot

A “note” in paragraph 1st step of procedure• Manual control is essential

Altitude and column Minimize Altitude Loss & Push

Nose down pitch control-ApplyNose down pitch trim-As needed• Reduce the angle of attack• Some altitude loss may be necessary

Thrust Maximum As needed• Max thrust can create pitch moment

CRM PM role not defined PM role clearly defined

Information presentation Paragraphs of guidance Procedural text

Actions(Boeing and Manufacturers Working Group)



Preamble to Stall Recovery Template

•Pilot careers – We fly airplanes from various airplane manufacturers

•Manufacturers should attempt to find commonality among procedures

•The template should be used by current and future aircraft manufacturers



Preamble to Stall Recovery Template (continued)

Process used in past initiatives:

Label the differences, find commonalities, create a simple, easy to understand template

•Upset Recovery Training Aid

•Stabilized Approach Recommendations Flight Safety Foundation)

•Smoke, Fire and Fumes industry template for Non Normal Checklist




•Label the differences – Stick pushers vs. stick shakers

– Turboprops vs. turbojets

– wing mounted engines vs. tail mounted engines

– Fly-by-wire vs. non-fly-by-wire

•Find the commonalities

•Create a simple, easily understandable Stall Recovery Template




•Rationale for each step is included

•Configuration changes are not included in the template

– Specific procedure for a particular airplane, OEM will provide guidance

•Manufacturers

– Deviate from template if the airplane's operating characteristics require it



Stall Recovery Template (With Rationale)

• Publish procedural steps, followed by

• Rationale

– Purpose of the step

– Reason for its sequential placement




•Apply to the majority of today’s airplanes– May deviate due to specific airplane

characteristics

•Typical difference– Configuration changes (such as flap extension)

could be required at a specific point during the procedure




Immediately do the following at the first indication of stall (buffet, stick shaker, stick pusher, or aural or visual indication) during any flight phases except at lift off

Note: Manufacturer’s Lift-Off procedures vary by airplane



Stall Recovery Template

1. Autopilot and autothrottle…………….…Disconnect

2. a) Nose down pitch control……………..Apply untilout of stall (no longer have stall indications)

b) Nose down pitch trim…….…………. As Needed

3. Bank………………………………..…….Wings Level

4. Thrust …………………………………….As Needed

5. Speed brakes…………………….…………...Retract

6. Return to the desired flight path

Copyright © 2011 Boeing. All rights reserved. Enhanced Stall Recovery

Immediately do the following at the first indication of stall (buffet, stick shaker, stick pusher, or aural or visual indication) during any flight phases except at lift off

Note: Manufacturer’s Lift Off procedures varies by airplane.

1 Autopilot and autothrottle……………………...Disconnect

Rationale While maintaining the attitude of the aircraft, disconnect the autopilot and autothrottle. Ensure the pitch attitude does not change adversely when disconnecting the autopilot. This may be very important in mis-trim situations. Manual control is essential to recovery in all situations. Leaving one or the other connected may result in in-advertent changes or adjustments that may not be easily recognized or appropriate, especially during high workload situations.


2 a) Nose down pitch control…Apply until out of stall (no longer have stall indications)

b) Nose down pitch trim..……………………...As needed

Rationale a) The priority is reducing the angle of attack. There have been numerous situations where flight crews did not prioritize this and instead prioritized power and maintaining altitude. This will also address autopilot induced full back trim.

b) If the control column does not provide the needed response, stabilizer trim may be necessary. However, excessive use of pitch trim can aggravate the condition, or may result in loss of control or in high structural loads


3 Bank………………………………………………..Wings level

Rationale This orientates the lift vector for recovery.

4 Thrust……………………………………………….As needed

Rationale During a stall recovery, many times maximum power is not needed. When stalling, the thrust can be at idle or at high thrust, typically at high altitude. Therefore, the thrust is to be adjusted accordingly during the recovery. For engines installed below the wing, applying maximum thrust can create a strong nose up pitching moment, if speed is low. For aircraft with engines mounted above the wings, thrust application creates a helpful pitch down tendency. For propeller driven aircraft, thrust application energizes the air flow around the wing, assisting in stall recovery.


5 Speed brakes………………………………………..…Retract

Rationale This will improve lift and stall margin.

6 Return to the desired flight path

Rationale Apply gentle action for recovery to avoid secondary stalls then return to desired flight path.



Thank you

Enhanced Stall Recovery Procedure_Philip Adrian

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