PPRuNe Forums - View Single Post - American Airlines Flight 742 "flight control system" problems
Old 24th Apr 2013, 11:12
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Ashling
 
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Confiture you misunderstand


Trimming does not mean you are in trim. How far the nose travels, and in which direction, when you release the stick will depend on were you or the aircraft have trimmed to. I made the point about trimming to illustrate one reason why releasing the back pressure is an inappropriate response to a stall warning. You have to lower the nose attitude, to reduce AoA, by looking out the front or, if IMC, at your AI or PFD.

No one disputes that there was an AoA margin spare, the issue is whether you can access it. In a 737 you would be into the shaker so you wouldn't do any better unless your into ignoring stall warnings which would be insane.

The following is from Airbus's submission to the NTSB

"During the remaining portion of the flight, the Aircraft remained in Normal Law, and on occasion was flown within the alpha protection range. Notably from approximately 150 ft down to the water impact the Aircraft was in slats/flaps configuration 2. During this time period the Aircraft was in the alpha protection mode which allowed the flight crew to remain focused on their priorities, conversely if the Aircraft had been a non fly-by-wire aircraft, the flight crew would have had to fly in and out of the stick shaker to maintain the desired descent profile."

Last edited by Ashling; 24th Apr 2013 at 12:44.
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