PPRuNe Forums - View Single Post - Are the MD-90's pylon flaps EVER cycled?
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Old 2nd December 2016 | 14:29
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WhiskeyNovember
 
Joined: Mar 2002
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From: N/A
Just found this.
• A pylon flap system, installed on the trailing edge of each pylon, provides increased aircraft nose-down pitching moment in the event a deep stall is encountered.
• Moving either control column to the forward stop activates the system. The pylon flap surfaces move from neutral position to fully deployed. Moving the control column off the forward stop causes the pylon flap surfaces to return to the neutral position.
• The blue ELEVATOR AT LIMIT light on the OAP illuminates to indicate that the pylon flaps and the elevators have reached the full down position, and will also illuminate to indicate full up position of the elevator.

Sounds as if when you do a full movement check if you don't get a blue limit light you have a problem with elevators or the pylon flaps, trouble shoot to find which is not bringing the light on.
Thanks so much for finding this. It doesn't seem to specify whether the pylon flaps actually deploy during a control check on the ground. It's possible they only ever deploy while in flight.

In which case, I still question how they can be checked and how it can it be ensured they will function properly when needed.
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