PPRuNe Forums - View Single Post - The Roller Coaster technique in Boeing 737's
Old 21st May 2026 | 06:54
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From: Ex-pat Aussie in the UK
Originally Posted by FullWings
I would also argue that the sim time would have been better spent training people how to fly NPAs without hitting something, given the extremely remote possibility of a trim runaway going undetected until it hit the stops and one of the commonest causes of CFIT back in the day...
Two instances I can think of - one a 737 at Amsterdam and one a Thompson at Manchester. For both, the pilots were distracted with very low thrust set and the trim rolled nose up due to the dropping airspeed. Then a Go-around is initiated and the autopilot disconnected.

As the trim is more powerful than the stab, the aircraft pitches up, beyond the ability of the elevator to correct it - i.e., full foward on the controls and still pitching up. Now if the autopilot had been kept in, the trim would be running forward, but in manual flight the startle can mean that the pilots don't think to apply the forward trim needed.
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