PPRuNe Forums - View Single Post - AF 447 Thread No. 6
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Old 17th August 2011 | 14:13
  #64 (permalink)  
CaptainGef
 
Joined: Aug 2011
Posts: 4
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From: Paris
Hello
If you read the graph p111 between 0211:00 and 0212:45
During all this time this is the stall warning the crew does not believe.
We can see Altitude does not vary too much and to quickly (37924 to 36068)
F/O pitch orders up and down.
Stabilizer from -3 to -13°
Speed is decreasing and as speed is decreasing, they don't see it and what does the THS do on FBW machine?: It tries to maintain flight path, so as speed is decreasing to maintain flight path the autotrim goes up to the limit, incidence is growing up to maintain flight path.
On a Boeing, even in alternate law, you would have to trim as speed decrease to maintain flight path, it would alert you that something is wrong.
Here, it is like if the pilot is being helped, without being conscious, to install the Airbus in the stall.
No sensation on the joystick, if he does not look sharply at his trim indicator, he does not see, he does not feel that the autotrim is trimming for him to install the stall !!
I think it is not the pitch orders that make the THS pitch up. It is the FBW system and this way does not help....

What do you think ?
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