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Boeing 777 engine-out cruise question

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Boeing 777 engine-out cruise question

Old 9th Feb 2016, 08:21
  #1 (permalink)  
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Boeing 777 engine-out cruise question

Hey guys

Just a quick question. Looking at the engine inoperative cruise technic in my manual, I've noticed a big difference when VNAV is engaged, and when it's not.

With " VNAV not engaged " :

- Select CLB/CON on MCP
- Select a lower altitude on the MCP
- Select FLCH and disconnect the A/T

Why would you disconnect the A/T right away in FLCH and not in VNAV ?

Sorry if the question seems stupid, or maybe I just miss a key point here, but I can't figure why..

Thanks !
fireball_23 is offline  
Old 9th Feb 2016, 08:35
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With VNAV engaged, the autothrottle will maintain MCT for the driftdown descent. With FLCH engaged, the autothrottle will reduce thrust - that may not be desirable if terrain is a factor.
BuzzBox is offline  
Old 9th Feb 2016, 08:43
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Better be quick disengaging the A/T after you select FLCH or it will close the thrust before you can blink!!

Why not select CLB/CON first, wait a sec while the Thrust advances then disconnect A/T, then select FLCH?
ACMS is offline  
Old 9th Feb 2016, 13:56
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Why not select CLB/CON first, wait a sec while the Thrust advances then disconnect A/T, then select FLCH?
When you select FLCH, the A/T's will re-engage so you'll have to disconnect them again anyway.
Gillegan is offline  
Old 9th Feb 2016, 14:48
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That makes sense now. Thank you so much for your help !
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