Originally posted by
airtren ...
Question: it is unclear what the "Stall Warning" curve is. Would you please clarify? Thanks in advance.
It seems obvious it is not the "Stall Warning" message given to the pilots, as that was,
afaik, not permanent/continuous.
Have a look at
HN39's post #70 where he explains the how the data was constructed.
With regard to the stall warning, it is designed to warn of an approaching stall and works on the basis that a stall is then avoided. When in ALT2 LAW the AoA value and the CAS must be within prescribed limits for the system to calculate, and when they fall outside, e.g. AoA > 30° and/or CAS < 60 KTS, the system determines there is No Calculated Data (NCD). No valid data has resulted in the SW turning off, and it appears that when the data became valid the SW resumed, but the application of NU commands to the SS has resulted in the SW stopping again. Result is an inappropriate action was rewarded.
Looking at the AoA curve in the
graphic, it bounces along the SW line as the aircraft pitches up into the climb, briefly triggering the SW. The Stall Warning sounds at 2:10:51 and continues sounding until shortly after the Capt. enters the FD. Though not shown on the graphic, it later sounds when the aircraft is established in the stall and the data is once more valid following ND inputs to the sidestick. NU inputs stopped it!