BOAC... I am not disagreeing with all you say
Where would this crew have been if they had not attempted the stall check but had a hard terrain warning and had done just that? Surely the first they might have known would be excessive pitch, low speed and a few hundred feet above the hard stuff?
Pretty poorly placed! However, to get in this situation:
- They would require a double, identical AoA failure (as happened here) that outvoted, ironically, the "good" AoA sensor. Probably not allowed for in design certification.
- Happen on the 1st sector post the maint error that caused 1 above (I now see there was a "vote" occurred, so there would have been a Status Message/PFR post flight)
- A Hard GPWS Warning (or Windshear requring full backstick).
I might add for others who keep saying the crew should have been warned, even in the exceptional test profile they were doing. I might say, if my life relied on it, I might check the AoA sensors were working prior doing the test (pretty easy to do)
It is not as simple as adding an "AOA Disagree" message. It is deeper than that... if you are going to add an "AOA Disagree", maybe an "IAS Disagree" might be an idea? There is one, but only on some more recent variants, and in this case would not have triggered...
NoD