Re:The Case Against Boeing
by mopsi on Saturday November 16, 2019 @09:35PM
(#21556211)
> Having it repeatedly come on and run is runaway trim
And they recognized it as such and completed the runaway trim checklist, but they couldn't use manual trim (as advised) to recover from the situation, because aerodynamic forces acting on the stabilizer overpowered them.
Two Swedish pilots demonstrated this scenario in a 737NG simulator: https://youtu.be/aoNOVlxJmow?t=606 Ethiopian pilots were in even more stressful situation, because they also had broken AOA sensor with unreliable airspeed indication, active left stick shaker, occasional terrain proximity warnings and overspeed clicker.
No procedures or training existed for the situation they were in. Pilots of early 737s were taught the so-called rollercoaster maneuver to temporarily relieve the load to allow manual trimming, but that was scrapped decades ago.
And they recognized it as such and completed the runaway trim checklist, but they couldn't use manual trim (as advised) to recover from the situation, because aerodynamic forces acting on the stabilizer overpowered them.
Two Swedish pilots demonstrated this scenario in a 737NG simulator: https://youtu.be/aoNOVlxJmow?t=606 Ethiopian pilots were in even more stressful situation, because they also had broken AOA sensor with unreliable airspeed indication, active left stick shaker, occasional terrain proximity warnings and overspeed clicker.
No procedures or training existed for the situation they were in. Pilots of early 737s were taught the so-called rollercoaster maneuver to temporarily relieve the load to allow manual trimming, but that was scrapped decades ago.