PPRuNe Forums - View Single Post - MAX’s Return Delayed by FAA Reevaluation of 737 Safety Procedures
Old 28th May 2019, 16:48
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MurphyWasRight
 
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Originally Posted by Fly Aiprt
One must remember that the 737 was a "certified" aircraft, and so was supposed to be trimmable at any speed within the flight envelope.
So there is nothing wrong with leaving full thrust with a stickshaker alarm at takeoff.

Duly warned and briefed pilots experienced great difficulties in the sim when confronted with the same scenario.
Even though nothing was at stakes, they say they had their hands full with dealing with the recovery and fighting tunnel vision.

What with a real unexpected alarm in a real aiplane with no previous briefing ?
And remember, the "certified" 737 was supposed to be hand trimmable at the time.

Only now do we know Boeing "autocertified" their airplanes, and there are suspicions of trim difficulties on the MAX as well as the NG.
Totally aggree with above, while leaveing power up was not ideal it was not a cause of inability to trim, snip from a post in other thread:

Known facts from, report.
Airspeed at start of first MCAS input 250 kts.
MCAS applied 9 seconds ND trim the ET pilot applied 3 seconds NU trim 6 seconds later.
MCAS acitvated 5 seconds after that but was interrupted at 6 seconds by 9 seconds NU trim. (possibly interrupted by trim cutout)

Total MCAS 15 seconds ND total pilot NU 12 seconds left the aircraft severely out of trim and just under VMO in under 40 seconds and likely unrecoverable using manual/mechanical trim.
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