Originally Posted by
Ian W
Just think Stab trim starts misbehaving it can be switched off in seconds and as shown by the Lion Air Flight the aircraft can continue and land - that is what Boeing expected _all_ pilots would do if there was a problem.
The trouble is that the AoA issue presents itself to the aircraft in the form of a stick shaker (that is loud enough, in my experience, to mask the sound of the trim wheel) and indications on the PFD of a stall.
Training is now is emphasising:
- At the first indication of a stall..
- Reduce the AoA
The poor old pilots presented with this scenario have:
Stall indication -> stall recovery.
The stall detection and airspeed/pitch correlation is wrong. Which to believe?
The violent noise of the stick shaker masks the insipid nose down trimming.
Any fix by Boeing needs to be tested so that the average pilot can cope, given the scenario above. Boeing just accounted for "the trim runs away",
which is not the same as stall/recovery/speed confusion/stick shaker cacophony. Boeing have been focusing on making the input to MCAS more reliable, but they really need to address what happens when the input is wrong, and the pilots are presented with a false stall indication.