PPRuNe Forums - View Single Post - The Roller Coaster technique in Boeing 737's
Old 24th May 2026 | 08:44
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BraceBrace
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From: Blue sky
Originally Posted by row13please
If it's free floating as in if the trim brake failed, I think was what he meant; someone had mentioned the brake.
Thanks, yes. If it's a "trim system failure", the yoke cut-out switches stop the runaway. If the brakes on the jackscrew fail, the yoke cut-out doesn't work and you need to grab the trimwheel and stop it immediately. In the first case, if manual trim is required but unable, the rollercoaster is an option. However, doing a rollercoaster with a free floating THS seems complicated to do from a CRM perspective. The easier solution shown to me was to "use the elevator to control the THS" to get in trim which requires opposite elevator movement to the rollercoaster.
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