MD-11F Speed Problem


I am currently flying the MD-11F from Chitose to a city in Russia. But I seem to have a problem. I am cruising at M 0.82, and the autopilot is really struggling to keep the speed. It is going N1 102% in order to keep the speed. Before I was cruising at M 0.85 and then I decreased to M 0.82 and then back up to M 0.85, so then the autopilot went full throttle but still stayed at M 0.82. All the engines are working fine from my knowledge and the readings. This isn’t bothering my altitude or anything, but it could become problematic with the fuel. Any ideas? Is it a glitch? Is it normal?

You may be too heavy for your current altitude. Long haul flights cruise at a low altitude initially, and gradually work their way up to their highest cruise later into the flight when they have burned more fuel. Maybe try a lower flight level.


Alright thanks will try, descending to FL310

That’s what Freddiefrogs meant:

Take a look :)


What is your load and cruising altitude and how far are you into the flight?

Cruising alt is FL390, now after your advice descending to FL310, load was set to heavy, and im about 400nm into the flight with 1700 to go.

alright will do so thanks :)

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FL390 is a bit too high for your current weight. You don’t have to descend all the way down to FL310, FL350 should be enough.

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alright thanks im now at FL330 and the throttle is at N1 77% so its solved now :)