Originally Posted by
Sailvi767
This appears to be a simple bent or bad AOA probe giving a erroneous stall warning. Poor jetway operation is the usual cause of a bent probe. I have had it on a L1011 and 727 plus several military aircraft. It’s a no brainer to handle on a non FBW aircraft. You know you are not stalling based on airspeed, attitude, power and phase of flight. Disconnect the electrical trim and fly the aircraft. When time permits pull the stick shaker circuit breaker. What is hard to understand is why over 4 flights this was not diagnosed or fixed. You wonder if the pilots or mechanics even knew the stall warning comes off the AOA probe.
Yes, except
this article (from further up the thread) states that the "broken" AOA sensor
was replaced. Apparently they are sending it back to mfr for examination, presumably to find out how it caused a crash whilst not even on the aircraft...
Does seem to mean that the earlier leaked maintenance reports that didn't mention AOA sensor were at best misleadingly incomplete. Also there is the possibility that the wrong sensor got replaced, or multiple duff sensors.
From the same article we also have (in relation to previous flight):
"The pilot's success became our reference to give a recommendation to Boeing so they could issue an advice for other airlines to follow the same procedures if the same situation occurs,"
while on
Boeing site it basically says "refer to existing procedures" - which is sort of implying that the crash pilots didn't follow them.
Also when comparing to L1011 & 727 era, need to remember that it's no longer three independent sets of sensors feeding three sets of gauges, but rather three sets of sensor inputs all going into multiple redundant ADIRUs which decide/calculate the "correct" data outputs, which can then be fed to either PFD. Any one sensor input being wrong
could (by design, it
shouldn't, but...) give incorrect or invalidated data on
any output from any/all ADIRUs - it all depends on ADIRU internal logic. AF447 threw up some "interesting" ADIRU logic at high (actual) AOA, similar may apply at erroneously-high sensed AOA.