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Old 20th Jul 2009, 14:54
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Hyperveloce
 
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How a pilot would react to stall alarms ?

Isn't there a past case, on an A340 in cruising phase (at FL370) between Paris and Antananarivo (F-GNIH) during which the pilot decided a nose down when stall alarms were sounded ?
Eurocockpit - Archives
added after reedition__________________________________________
before the problems with the airspeeds, the PF had reduced the speed to Mach 0.80 ("a little bit over the green dot") after the plane had entered turbulences not detected by the radar. So that when the stall alarms sounded (due to rolling back airspeeds due to Pitot freezing), maybe it was logical that he thought that they were justified (being just "a little bit over the green dot") and reacted accordingly ? (nose down & descent)
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I am also trying to see whether the A/THR could have had a similar reaction just before its disengagement (increasing thrust level to correct a spurious airspeed decrease just before being put off line), diminishing the upper aerodynamic margin. And also at A/P level (disengagement => an ongoing phenomenon compensated by the A/P before its disengagement is let free to drift/amplify when the A/P goes off).
Jeff
PS)
-these stall alarms occured approx. 30 s after the sequence of fault reports incl. AP & A/THR off in the Air Caraïbe case, a critical phase during which the crew are already busy to understand/isolate the faults, to apply the check lists/procedures and to pilot manually.
-the stall alarms immediatly follow the AP & A/THR off for the flight FGNIH AF908 CDG - TNR

Last edited by Hyperveloce; 21st Jul 2009 at 17:49. Reason: elapsed time between A/P off & stall alarms
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