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Old 1st Apr 2021, 15:32
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Join Date: Oct 1999
Location: Up there
Posts: 186
APU to pack and packs off takeoffs are allowed on PW4062 powered B747-400ERFs.

Regarding the leading edge flaps they are mechanically extended via pneumatic or secondary electrical.

There was an accident within the first years of 747 service where a bleeds off takeoff was attempted however the bleeds were selected off prior to selecting flap. So the leading edge failed to extend. The green LE extended lights were then added and thus the call “20/20/green” to cover the inboard, outboard and leading edge flap positions.

Last edited by CCA; 1st Apr 2021 at 15:44.
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