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WacUK

MD11 Autoflight Problem

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Hi,I'm having a problem when pressing the AUTOFLIGHT button during take off.On the PMDG wiki site it says - "The autothrottle and autopilot systems on the MD-11 are NOT independent of each other in the way that they are on Boeing aircraft. Before takeoff, pressing the AUTOFLIGHT button on the FCP arms both the autothrottle and the autopilot takeoff modes. Advancing the throttles manually past around 60% N1 will cause the autothrottle system to actually engage and begin controlling thrust. There is an audible click sound from the panel when this happens. After takeoff, press Autoflight again to do the equivalent of pressing one of the autopilot CMD buttons on a Boeing. This will actually give control of the pitch and roll modes over to the AP. From this point on, the two systems are completely unified and essentially operate as a combined system until disengagement at landing."When I press the AUTOFLIGHT button for the second time just after take off (about 400feet) the autopilot system disengages and I get an audible warning. The only way I have found to solve this is to keep pressing the AUTOFLIGHT button several times until it engages the autopilot again.Does anyone have any idea's what I'm doing wrong?

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Be sure to press it AFTER passing 400 ft. If you press it too soon (before passing 400 ft), the AP will disengage, etc. I always press it (at least when I want to use the AP at that moment) when I am at least at 500, just to be sure. :( It's only a matter of seconds.

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I am sure it is 400ft AGL (RA), though I am sure someone will correct me if I am wrong...I tend not to be in the position of pressing any buttons so shortly after takeoff... so I don't get to push AUTOFLIGHT the second time until I am over 400' AGL :DThis "trying to be multicrew with one pair of hands" is hard work :DAndrew

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Yes, it's AGL RA indeed: don't watch the alt tape but the radar altitude! Seemed logical to me, but thanks for adding it. :(

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Hi,I'm having a problem when pressing the AUTOFLIGHT button during take off.On the PMDG wiki site it says - "The autothrottle and autopilot systems on the MD-11 are NOT independent of each other in the way that they are on Boeing aircraft. Before takeoff, pressing the AUTOFLIGHT button on the FCP arms both the autothrottle and the autopilot takeoff modes. Advancing the throttles manually past around 60% N1 will cause the autothrottle system to actually engage and begin controlling thrust. There is an audible click sound from the panel when this happens. After takeoff, press Autoflight again to do the equivalent of pressing one of the autopilot CMD buttons on a Boeing. This will actually give control of the pitch and roll modes over to the AP. From this point on, the two systems are completely unified and essentially operate as a combined system until disengagement at landing."When I press the AUTOFLIGHT button for the second time just after take off (about 400feet) the autopilot system disengages and I get an audible warning. The only way I have found to solve this is to keep pressing the AUTOFLIGHT button several times until it engages the autopilot again.Does anyone have any idea's what I'm doing wrong?
I have a button programed on my joystick to activate autoflight. One thing that I have noticed is that it seems that If I press the button on the instrument panel with the mouse to activate autoflight on the ground and then use the joystick button once airborne I get the same thing that you describe. However, if I use the joystick button to activate on the ground and then also once airborne it works fine. The same thing applys the other way. Mouse push on the ground mouse push in the air. I was running into this because I would always push the button on the panel while on the ground because I didn't need my hands on the controls. I would then use the joystick button once in the air to avoid taking my hands off the stick.Just one possiblity...Steve G

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