Originally Posted by
Alchad
It seems to be accepted that there are such similarities between the Indonesian and the Ethiopian crashes that – I suspect – a lot of people are assuming the cause of the accidents will also be similar. However, one difference between the two crashes which doesn’t appear to have aroused all that much speculation, at least as far as I can determine, is the fact that the Ethiopian 737 only managed to get to perhaps 1000 feet (according to Flightradar24), whereas the Indonesian 737 appeared to achieve 5000 feet and the pilots consciously settled for that altitude.
This is where my non- aircraft background becomes apparent and the reason for my question; which is basically what caused ET 302 to be unable to get above 1000 feet?
Minimum flap retraction altitude for B737 is 400 ft so possible MCAS-activation at low altitude.
Also there seems to be an assumption that the MCAS would bug them continuously after that unless they switched trim off. In the LionAir crash prel report a difference of 20 deg throughout the flight and stick shaker active for most of the rest of the flight. I e there seems to be a systematic error in one of the AoA sensors that would only activate shaker when they flew with an actual AoA above a certain level. Same would then hold true for MCAS-activation.
With just the "right" systematic error in one of the AoA-sensors ET302 could have been perfectly trimmable flying at constant altitude with AoA below the threshold. As soon as they tried to ascend increasing true AoA to proper MCAS-activation angle minus systematic offset they would have been "pushed down" but could have trimmed out again. So they are in a "perfectly good airplane" as long as they zoom along at breakneck speeds at a constant altitude above sea level. If ground level (above sea level) increases they would be destined to meet with terra firma sooner or later...unless they used the elevator...and got hammered by MCAS again.
And for the complaints about their speeding: Thrust reduction? No go. You'd sink unless you increased AoA above the threshold...and got hammered again.´´´´´´´