PPRuNe Forums - View Single Post - Ethiopian airliner down in Africa
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Old 28th Apr 2019, 23:53
  #4538 (permalink)  
Join Date: Aug 2017
Location: London
Posts: 92
Originally Posted by 737 Driver View Post
exactly how long should a qualified 737 type-certified Captain who is hand-flying the aircraft let the trim run in one direction before he/she does something about it?

In quiet cockpit, vmc, no distractions, no turbulence, hands on controls: 3 seconds. 1: a/c is just "doing its thing". 2: thats weird. 3: wtf? Hit elec trim.

But. With stick shaker distraction: add time. With any other alarm, add more time. Add IMC, double it. If you're concentrating on another task: Add time. With noise that masks clacks: more time. Add "I have control" there's another half second. Add fatigue: more time.

MCAS is a slow-motion catastrophic control surface failure, taking 12 seconds. (For those who haven't followed all 228 pages of this thread, see this post detailing why MCAS is so insidious and lethal to a pilot.) You're treating it like an engine fail on takeoff. It has more in common with wonkazoo's snapped rudder cable. An engine fail on takeoff you'd pretty much expect to see at some point in your career. Before Lion Air and ET, no-one would be expecting to see trim runaway. This surprise factor again adds time.

They ran out of time.

Every time you say 'just fly the plane' or 'basic airmanship' or 'get another career' you're completely ignoring human factors. This is as dangerous as not knowing how to fly the aircraft. And this is why you're getting such a deservedly robust response from others on here.
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