Drift down ROD one engine out 737NG

[Driver 170]

Hi,

after disengagement of A/T, set MCT and allow the aircraft to decelerate to the one engine out speed, you then select LVL CHG. what is the expected rate of descent with one engine set at MCT?

thanks
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[rudestuff]

That depends on how heavy and how high you are.

Who says it's going to slow down and descend? Do all that at FL100 and you'll be going up.
But assuming you're high and heavy, your rate of descent will be pretty gentle, reducing all the time until the plane finds its equilibrium altitude for want of a better description. If that point is higher than you expected it will stop descending if you don't touch the levers - regardless of what's in the ALT window. That's my guess anyway.

[Johnny F@rt Pants]

Not very high, usually just a few hundred feet per minute.

[Driver 170]

Thanks for the response guys.

[Driver 170]

Back to this guys!

Practicing on my sim with QRH NNC OIL FILTER BYPASS

i actioned the QRH (737 NG) Lead to engine failure / shutdown checklist. I set disengaged A/T, set N1 MCT and set the thrust and hit LVL CHG at 225kts.

Driftdown - FL290

Once at FL290 i set LRC 280kts and carried out PIOSEE, One engine INOP landing checklist

my question is it ok to then set thrust levers to idle for descent to land at nearest suitable airport?

[Chesty Morgan]

Only drift down when you need to. No point staying at 290 when you're trying to land!

[Driver 170]

Hi, i had no option after shutting down engine 2 because the speed 250 kts started to decline?

[Chesty Morgan]

To clarify my point if you're close enough to an airport, there's no terrain or traffic to affect your descent then there is really no need to carry out the drift down maneuver. There's nothing wrong if you do do it as it will give you more time to make a decision if you need some.

[Denti]

That is why Airbus specifies two different procedures for engine failure in cruise. The obstacle strategy is basically a drift down, while the standard strategy leads to a highspeed descent enabling windmill engine start should that still be available.

[Driver 170]

Hey, that’s fantastic information. I suppose this is down to airmanship and depending on the severity of the failure if you need to get down quick or not.

definitely terrain wont be a factor as the highest peak in Europe is 18400ft and usually max altitude for one engine on a NG is about FL240 upwards for around 60t I believe.

[Driver 170]

Hey, quick question again. Is it ok to close the thrust levers with OEI from Cruise to get down quicker if you don’t want to driftdown?

[Chesty Morgan]

Absolutely.