4 ms·
Trim controlling stabilizer, yoke controlling elevator, and elevator being unable to counteract the more extreme ends of trim settings, is part of the original
by cmurf 8y ago
Trim controlling stabilizer, yoke controlling elevator, and elevator being unable to counteract the more extreme ends of trim settings, is part of the original 737 design. They all behave that way, and 737 pilots are aware of this, and know they must neutralize trim to have ample elevator control.
However, only the 737 MAX has MCAS, and MCAS doesn't take airspeed into account. An appropriate corrective action for a low airspeed stall, will be way too aggressive for a high airspeed stall (a rare event, suggests overly aggressive dive recovery leading to a stall). And designers + regulators assumed that pilots would treat such behavior the same as an ordinary runaway trim incident, but does it seem ordinary or is it a shockingly bad overcorrection?
We've seen many times the scenario where pilots become so surprised at a particular situation that their rational ability to work through the problem can be compromised. Yes, transport pilots are substantially trained to avoid such a compromise, but problems at low altitude combined with the lack of a consistently positive rate of climb is an urgent situation. Pilots are hyper aware that recovery from either a dive or stall consumes a huge amount of altitude, which you simply don't have at low altitude. That itself could delay proper decision making: i.e. automation has betrayed us for unknown reasons, disable it now.
With MCAS disabled, what's the 737 MAX stall behavior like? Is it meaningfully easier to unwittingly get into a stall?