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Guest cliffie1931

Why can't I control the MD-11 speed?

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For two weeks I've tried to fathom out why I can't take off without the throttle staying at adequate climb power. But I haven't been able to find the solution.I engage Autoflight above 400 ft at which time the EPR is way above 1.1. At 1,500 ft I engage the PROF button. Then soon afterwards, before gaining any considerable height, the EPR drops to ablout 0.9 and we lose height.Sometimes I only engage Autoflight when we're pretty high and then, after engaging Autoflight and the PROF button, we carry on as normal with no power loss.Could it have something to do with the low temperatures? Or what else could be the cause of the problem?I've attached a picture that I hope may be helpful.Cliff

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The picture indicates no prof or ats active. Also, I see no landing altitude, which means the FMS has not been told where it is going. Finally, the picture is too late... the problem was either in preflight or immediately after rotation.Tell us what you are doing and someone will let you know what you are missing or doing wrong.

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'IDLE CLAMP' in the vertical control window of the FMA shows that you are in Level Change descent, so idle thrust is normal.It's abnormal that you get into this mode soon after take-off so I guess there's a misunderstanding in the flight programming?From your picture it looks like you want to fly a Dover SID from EGLL.Assuming the FMS has been correctly programmed as in the tutorial, before take-off in the autopilot control panel arm navigation and autoflight and set 6,000ft as the first altitude constraint.The FMA should read something like 164PITCH / TAKEOFF AP OFF / T/O CLAMP 6000When you now advance the throttles for takeoff the ATS system changes from CLAMP to THRUST and then above 80kt back to CLAMPAt say 500ft engage the autopilot and at 1500ft agl PUSH (don't pull!) the PROF button.The FMA should now show:164PITCH / NAV AP1 / CLB THRUST 6000then assuming you've cleaned up, at 6,000ft it should show:250 THRUST / NAV AP1 / HOLD 6000If you then want to climb further to 30,000ft wind it into the altitude window and either push for profile climb (FMA values magenta) or pull for level change (FMA values white).ChrisAnd by the way in Europe we fly in Mb or Hpa, not inches...!Chris

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The picture indicates no prof or ats active. Also, I see no landing altitude, which means the FMS has not been told where it is going. Finally, the picture is too late... the problem was either in preflight or immediately after rotation.Tell us what you are doing and someone will let you know what you are missing or doing wrong.
Thanks Dan and Chris.You've certainly put me back on that old learning curve and given me something to chew on.....................I may come back again after I've spent more time at it. Cliff

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Cliff, are you pressing AUTOFLIGHT once before takeoff and then advancing the throttles? This is the correct procedure - you want to press the button once on the ground, this arms the whole system basically - as you advance the throttle you'll hear a click passing around 70% N1 or so and the AT will take over. Before advancing the throttles you can arm NAV, PROF etc and those will engage at the appropriate time. Press AUTOFLIGHT a second time after takeoff and the AP will actually engage and begin following the flight director commands...

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As everyone said here, go trough the tutorial flight again and you should do it correctly afterwards.

  • Configure correctly your FMS
  • Arm NAV and PROF mode before take-off
  • Arm your auto-flight and auto-throttle pressing the AP button before take-off

I would add if you want to make your plane follow the requested speed (not a magenta speed then but a blue one on your PFD), you have to PULL (right click) the speed button (when the cursor is an open hand). Note your required speed is shown ad yellow because it exceed current flaps configuration maximum speed but if you retract your flaps accordingly with your speed increasing, you should have no problem.Should I say you have not followed carefully check-list because you still have your APU active. I suggest you really go trough the tutorial flight again to handle basics of this plane.Regards.

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Cliff, are you pressing AUTOFLIGHT once before takeoff and then advancing the throttles? This is the correct procedure - you want to press the button once on the ground, this arms the whole system basically - as you advance the throttle you'll hear a click passing around 70% N1 or so and the AT will take over. Before advancing the throttles you can arm NAV, PROF etc and those will engage at the appropriate time. Press AUTOFLIGHT a second time after takeoff and the AP will actually engage and begin following the flight director commands...
Yup Ryan, that's just what I've been doing.Where I may have been going wrong is to program the FMCU with the destination but withour going as far as selecting a specific runway and relevant STAR; hence no destination altitude had been entered. I'd been under the impression that this choice could be left till well into the flight.One way and another, using the advice from all you guys, the problem may have been solved. I need to try more departures before knowing for certain.As luck would have it I'm privelged to have a retired British Airways Pilot spending a few hours with me on Wednesday. An exiting prospect and I'm hoping to learn much from him.

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