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Old 11th Sep 2014, 03:03
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_Phoenix_
 
Join Date: Aug 2014
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why capt. Dubois exclaimed "It's impossible!"

@Lonewolf 50

The poignant "it is not possible" (in Fr, impossible) remark points to him not believing something ...
Capt. Dubois didn't comprehend why the aircraft was climbing while sidestick was forward

see below the situation dissected:

CVR // sidestick position // pitch attitude

2 h 12 min 32,4 Dubois: No you climb there // aft -8 deg // up 5 deg
2 h 12 min 32,8 Bonin: I’m climbing okay so we’re going down // full forward 16 deg //up 6 deg
2 h 12 min 34,2 Robert: You’re climbing // full forward 16 deg // up 8 deg
2 h 12 min 39,2 Bonin: okay we’re in TOGA // forward 10 deg // 0 deg
2 h 12 min 41,9 Bonin: On alti what do we have here? // forward 10 deg // down 3 deg
2 h 12 min 43,8 Dubois: (…) it’s impossible // aft -4 deg // down 3 deg

the reconstruction scene:
https://www.youtube.com/watch?v=XAom...ailpage#t=2475

It looks like a dejavu of XL888 crash.
.. flight control system automatically “trims” the THS to max nose up. The moment arm overcomes the elevator authority. The increased speed only serves to force the aircraft in a perpetum stall, like a dart plane, see pitch attitude graph

Last edited by _Phoenix_; 11th Sep 2014 at 03:28. Reason: repetition removed
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