Hi HazelNuts39,
Thank you sir, and VERY good work (as usual)
That's exactly what I expected:
https://docs.google.com/leaf?id=0B0C...zZDlm&hl=en_GB
Better posting a smaller representation directly for discussion:
Originally Posted by HazelNuts39
Airspeed from groundspeed, V/S, windspeed and temperature is shown on this graph: CASfromGS, It is based on wind 45 kt @125 deg, ISA +11 deg C, DFDR data for v/s, altitude and HDG.
The blue dots are Mach from ADR, pink is Mach from GS, wind and v/s, and the green dots show the corresponding CAS.
This is showing where the stall/speed alarm system is flawed in relation to indicated airspeed issues:
"Sensed/indicated" airpseed drops below 60 kt, alarm stops because alpha is NCD. At first sight, it seems fair considering the very remote possibility that an aircraft would still be "flying" at such a low airspeed. Also, IAS went below limits of 30 kt "sensed", hence NCD is displayed on main instruments (only ISIS displays IAS down to 0)
While in reality, this aircraft airspeed was never under 100 kt but stayed in the range of 105-175 kt, where, of course it was not "flying" but "stalling". During about 1 minute, 0211:45 - 0212:45, airspeed was not that far from "flying again" values. The reversal of airspeed tendency happened when engines were set to IDLE.
With correctly interpreted informations (and test pilot skills) this aircraft might have been fully recoverable during this whole minute, as late as 0212:45, and maybe later providing enough altitude remained; Even THS setting is not an issue at such a low airspeed. Elevators are powerfull enough to overide it and trim back; this aircraft is longitudinaly very stable and thrust management could have made the difference for pitching down to "flyable" alpha.