PPRuNe Forums - View Single Post - Boeing 747-400 water landing evacuation procedure
Old 10th Nov 2019, 08:13
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wiggy
 
Join Date: Feb 2001
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Originally Posted by washoutt
In the you-tube film above, the slats are retracted upon deployment of the thrust reversers, which makes sense. But when the TR are closed, the slats -while taxying- are deployed again. I'm not a pilot, but an engineer, so I've no idea why that is. Can anybody enlighten me? .
As I recall it ( with a "it's been ten years plus so health warning") the inboard/mid-span leading edges retract on selection of reverse to prevent them being damaged during reverse thrust operation ( ?FOD). Once reverse is cancelled the LEs should then automatically return to the position appropriate to the selected Flap setting..(and FWIW the slats work in harness/are controlled by the Flap setting/Flap lever, there's no separate slats control). Bearing that in mind..

1. On approach/touchdown with Flap selected the inboard/mid LEs will be "out".

2. On roll out with reverse selected the inboard/mid LEs will motor "in",

3. Once reverse is cancelled, usually towards the very end of the rollout, those LEs will then motor "out" again because usually at that point landing flap is still selected,

4. Once off the runway and when the after landing procedure is performed the flap is selected up and the LEs will motor "in" again..

That's the theory.....

Last edited by wiggy; 10th Nov 2019 at 08:43.
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