PPRuNe Forums - View Single Post - Boeing 737 Max Software Fixes Due to Lion Air Crash Delayed
Old 19th Apr 2019, 07:41
  #703 (permalink)  
safetypee
 
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​​​​​​Ian W, #698 / #696

Importance’ is in the context of a Fight Safety review and training requirements post MCAS accidents - learning from past events.
The argument for ‘feel awareness’ is both for normal operations, where the wider than normal flight envelope might be less familiar - automation dependency view; and in abnormal operation as experience of failure conditions in comparison.
Trim runaway - directional nose up/down and increasing force with trim deviation and speed, hence speed management, and for ‘feel shift’ with an overall increase of stick force (normally near stall but what about failures at other times).

There is supporting evidence for feel issues from incidents in the 737, I recall a severe roll upset due to fuel mismanagement, only apparent after autopilot disconnect (AAIB?). The crew expected the aircraft to fly wings level with zero force and stick central, thus their datum was offset and the aircraft continued to roll (try this as a surprise event in the sim).
Events in other aircraft show similar problems in pitch, where the expected norm - in trim, zero force, was taken as datum, but with trim offset the aircraft flight path continued to deviate ‘unexpectedly’, often interpreted as ‘loss of control’.

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