PPRuNe Forums - View Single Post - AF 447 Thread no. 4
View Single Post
Old 16th Jun 2011, 16:40
  #41 (permalink)  
jcjeant
 
Join Date: Aug 2009
Location: Germany
Age: 67
Posts: 1,777
Likes: 0
Received 0 Likes on 0 Posts
Cool

Hi,

Like some others, I have a feeling that the PF may have experienced some difficulty in achieving left-stick without up-stick when unexpectedly handed the baby at 4am CET. I also hang on to the faint hope that the BEA may acquire ASI 2 data from the QAR. Unless it was over-reading, I cannot understand why he perpetuated the mistake as the aircraft climbed.
The BEA note:

From 2 h 10 min 05 , the autopilot then auto-thrust disengaged and the PF said "I have the
controls". The airplane began to roll to the right and the PF made a left nose-up input. The stall
warning sounded twice in a row. The recorded parameters show a sharp fall from about 275 kt
to 60 kt in the speed displayed on the left primary flight display (PFD), then a few moments
later in the speed displayed on the integrated standby instrument system (ISIS).
Note 1: Only the speeds displayed on the left PFD and the ISIS are recorded on the FDR; the speed
displayed on the right side is not recorded.
Note 2: Autopilot and auto-thrust remained disengaged for the rest of the flight.
At 2 h 10 min 16, the PNF said "so, we’ve lost the speeds" then "alternate law […]".
Note 1: The angle of attack is the angle between the airflow and longitudinal axis of the airplane.
This information is not presented to pilots.
Note 2 : In alternate or direct law, the angle-of-attack protections are no longer available but a
stall warning is triggered when the greatest of the valid angle-of-attack values exceeds a certain
threshold.
The airplane’s angle of attack increased progressively beyond 10 degrees and the plane started
to climb. The PF made nose-down control inputs and alternately left and right roll inputs
. The
vertical speed, which had reached 7,000 ft/min, dropped to 700 ft/min and the roll varied
I don't know (or on what they base their feeling) why many people think the pilot perpetuated command to climb ... as the BEA note is clear about ...

The airplane’s angle of attack increased progressively beyond 10 degrees and the plane started
to climb. The PF made nose-down control inputs and alternately left and right roll inputs
BTW .. exactly like the Perpignan pilote made.
jcjeant is offline