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Boeing FMC manipulation

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Old 10th Apr 2016, 18:26
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Boeing FMC manipulation

Following an engine issue for instance that requires that eng to be run at idle in flight, having say followed the engine limit surge stall check list on a twin engine is it advisable to select the FMC engine out performance page and execute?
Or just interrogate it for info without executing ?
Any thoughts or expansions on the above most welcome.

Last edited by hulabaloome2; 10th Apr 2016 at 19:05.
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Old 10th Apr 2016, 19:57
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I don't know which Boeing you're talking about, but as a matter of principle any fault requiring the reduction to idle of an engine I would treat as an engine failure and fly the aircraft accordingly. If you are at cruise altitude and you have to idle an engine, clearly you will have to descend anyway.

I have encountered a similar situation in a bizjet where the engine was left running at idle thrust (due to an Engine Control unit failure creating surge like symptoms) but the aircraft was flown using single engine procedures for approach and landing.

On the 737 the ENG OUT CRZ isn't executable anyway, but merely gives information.
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Old 11th Apr 2016, 10:05
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I agree with Jwscud in regard to treating it as an engine failure.

On the 777, I would suggest executing the ENG OUT CRZ as it will set the thrust reference to CON, rather than CLB. That will allow the aircraft to use Max Continuous Thrust and give you a lower vertical speed in the descent.
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Old 11th Apr 2016, 10:50
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Isn't CLB CON AND MCT the same up there anyway?
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Old 12th Apr 2016, 14:10
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Isn't CLB CON AND MCT the same up there anyway?
Typically max Climb and Max Con are the same above 30K. But single engine (or one engine at idle) you're unlikely to maintain 30k, so you'll get the difference between Con and Climb below 30k.
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Old 12th Apr 2016, 16:29
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It's a scenario I used to give as an RST LOFT in the sim. I was amazed at the confusion it caused to the less sharp crews. The QRH trained monkeys had a most confusing time, especially if the Capt was one of those and the F/O more free thinking. That in itself caused a CRM issue.
What was staggering is how many crews did NOT brief and set up for a F15 SE landing, and then on finals suddenly started thinking that F40 SE was not a good idea. They then made a GA and started it allover again. They had not processed the SE status at all including NNC landing distance, fuel, etc etc. It was a horlicks, but a lesson well learnt. However, it should not have been necessary for a clear thinking Captain. Indeed I would prefer it on a command course. The real world does not know a QRH exists.
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