Concours77
Why is the Report silent about his ND input being interrupted by STALL STALL just seconds after manual flight begins?
I suggest you read the accident reports before posting.
Page 89.
https://www.bea.aero/docspa/2009/f-c...p090601.en.pdf
"The activations of the warning picked up by the CVR were identified as occurring
at between 2 h 10 min 10.4 and 11.3 and between 2 h 10 min 13 and 13.4. The
short duration of activation did not make it possible to detect it from the “Stall
warning” parameter, but the FWC 1’s “Master warning” parameters were triggered
on one point at this time. However, this warning should have continued until about
2 h 10 min 15.5, and then have been triggered again between 2 h 10 min 17 and 19.
The disabling of this warning was probably due to the fact that, between 13.4 and
15.5 and then between 17 and 19, and possibly at other times, the three Mach values
were abnormally low (three Pitot probes iced up). The warning triggering threshold
then suddenly increased to values of about 10°, much greater than the recorded
angles of attack, which led to the warning stopping.
After 2 h 11
Analysis of the parameters showed that the stall warning stopped concomitant with
the invalidity of the three angles of attack, and was triggered again when at least one of
them became valid again. In view of the extreme values of angle of attack experienced
by the aircraft, the change to the threshold as a function of Mach was secondary.
The stall warning triggered again ten times after 2 h 11 min 45; a correlation was noted
between this triggering and a pitch-up input by the PF on two occasions, between
2 h 12 min 52 and 2 h 12 min 57 then between 2 h 13 min 52 and 2 h 14 min 02."
NB. Airbus has since redesigned the stall warning logic.
"STALL WARNING enhancement: Stall warning will work when:
Undetected erroneous computation of pitot
Pitot out of the airflow
Pitot obstructed by ice or any foreign material at any speed (function now possible below 60 kts)"