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Old 1st Jun 2011, 06:53
  #1218 (permalink)  
fgrieu
 
Join Date: Jun 2009
Location: Paris, France
Age: 62
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Effect of the position of the THS

From 38 000 ft down to 0, the trim/THS was at 13° nose up.
Starting around 2 h 12 min 17, still well above 10000 ft, there was an apparent attempt to get out of stall: nose down stick with engines around 55% N1. It did not work out. I'm trying to understand how the position of the THS is related to that failure.

Questions:
- Can it be determined what the flight law was during that nose down input?
- Is this mode consistent with the THS remaining static?
- Does this mode allow full deflection of the elevator?
- Was getting out of stall feasible despite the position of the THS?
- Do procedures to get out of stall, as (I guess) practiced in simulator, include manual action on the trim to get the THS back to neutral or nose down (or on the contrary is it customary to assume autotrim will take care of the THS)?
- Do these standard procedures include extending flaps to some degree, which is not mentioned in the BEA report?

Full disclosure: I'm not a pilot; I'm an engineer working on systems where security (not safety) is critical, and I like to understand by myself how failures happen.
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