PPRuNe Forums - View Single Post - Boeing advice on "aerodynamically relieving airloads" using manual stabilizer trim
Old 13th May 2019, 12:52
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safetypee
 
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HowardB,

Link -
https://aviationweek.com/commercial-...b3175d28a7b54a

Highlights for the non registered (free).

‘A simulator session flown by a U.S.-based Boeing 737 MAX crew that mimicked a key portion of the Flight 302 accident sequence suggests that the crew faced a near-impossible task of getting their 737 MAX back under control, and underscores the importance of pilots understanding severe runaway trim recovery procedures.’

‘What the U.S. crew found -. Keeping the aircraft level required significant aft-column pressure by the captain, and aerodynamic forces prevented the first officer from moving the trim wheel a full turn.
They resorted to a little-known procedure to regain control.’ (YoYo Roller Coaster)

The excessive descent rates during the first two steps meant the crew got as low as 2,000 ft. during the recovery.

The article continues discussing aspects of the recent accidents, worthy of inclusion in previous (closed) threads; failing that - register with AvWk for info.

Concluding:-
‘The simulator session underscored the importance of reacting quickly to uncommanded stabilizer movements and avoiding a severe out-of-trim condition, one of the pilots involved said. “I donʼt think the situation would be survivable at 350 kt. and below 5,000 ft,” this pilot noted.’

“This is the sort of simulator experience airline crews need to gain an understanding of how runaway trim can make the aircraft very difficult to control, and how important it is to rehearse use of manual trim inputs,”

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