PPRuNe Forums - View Single Post - AF447 Thread No. 3
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Old 31st May 2011 | 08:36
  #850 (permalink)  
sensor_validation
 
Joined: Jul 2009
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From: UK
@bekolblockage

You have to go back more than 43 pages! The ballistic zoom-climb trajectory demonstrated by the A340 was suggested as soon as the proximity of the crash site to LKP confirmed - and the FDR plots in Appendix B of the AAIB report re-published a couple of weeks ago. But the A340 in daylight did not lose air-speeds so flight control laws and protections not the same as AF447 - but was way above safe height and must have been very close to stall at the apogee at FL 384 "where the airspeed had decayed to 205 KIAS and 0.67 Mach even though full thrust had been applied". Full thrust was from protection even though A/T off.

[edit] Note that the pitch-up and climb was auto control system induced, the recovery thanks to the pilot requiring bold inputs to break an AoA hold law. There is no mention in the report of stall warning so pitch and AoA correctly managed in the recovery.

There is some uncertainty on these forums as to what/when triggered the pitch up. The A/P kicked off due to overspeed in clear-air turbulence - pitch up seems more likely due to protection against overspeed than the stated "corrected or phase-advanced angle of attack" "excursion beyond alpha prot"?

Last edited by sensor_validation; 31st May 2011 at 10:31.
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