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Guest saupatel

PMDG 747 Questions

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Hi, i had a few questions about the PMDG 747. - After takeoff, for some reason, i cant get the autopilot to get on the course i have programmed into the FMC. All i do is after takeoff, i wait for the departure control to clear me to my route then i turn on the autopilot and LNAV. the FMC progress never goes past the first waypoint. The aircraft circles back again to the first waypoint after its past it. If i fly manually past the first waypoint then turn on LNAV, the aircraft wants to go back to the airport (even if i delete ,from the FMC, the waypoint i have just passed). - i tried flying manually (HDG set) and autopilot controlling climb. Around FL250, i hear this loud chattering noise which doesnt stop until the aircraft is over FL310 (approx). The aircraft is not in a stall either. - around FL250 (when the above chattering occurs), the autopilot starts switching to FL-CH where even though i set the altitude to FL310, it stabilizes to some mid level around FL260. This is confusing because if i try to override the FL-CH and set the ALT HOLD or VS, the autopilot switches back to FL-CH. i have tried 4 flights so far and everyone has had these issues. I am sure i am doing something wrong. Would appreciate if someone could point me in the right direction to fix these issues. Meanwhile i will go digging into the flight manual for info. i have been flying all the variations of the PMDG 737 and have never seen anything similar. Ofcourse the 747 is nothing like a 737 :). thanks in advance. regards, Saurabh

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Assuming you've read the manual (you HAVE read the manual right?) then there is an excellent tutorial available in the Avsim libraries that will assist you.By your description you've obviously worked out a lot of the procedures already but it also sounds to me like you're bringing some 'default MS autopilot' habits into the 747, which is a common and troublesome problem. Also, the 747 is a heck of a lot heavier than the 737NG series so there are some surprisingly different behaviours to be conscious of.Check out the tutorial and if you need any help from there, come and see us!

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Saurabh, it sounds like the LNAV is functioning properly. Perhaps this is an operator error. If you do any manuevering after takeoff and prior to engaging LNAV, then you are putting yourself in a precarious position concerning the use of LNAV. If you are not arming LNAV prior to takeoff you are going to have to tell it where to go. So, once released by ATC to your own navigation, then you will have to fly a "direct to" to the first wauypoint. LNAV assumes that is going from the previous wauypoint to the next one. In this case it assumes you are flying directly from the departure runway to your first waypoint with no manuevers. If you are under ATC control I would pretty much guarantee you are nowhere near the departure runway and have done some vectored flight. When released by ATC to your own Nav, go to the LEGS page and do the "direct to" procedure. Then arm LNAV. This should set the FMC properly for the remainder of your flight.

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Hi guys, i am first going to read the instructions more carefully this weekend and try one flight out again and see what happens. I will also try the suggestions by DAN. I will post an update on monday and let you guys know if i have rectified the issues i have posted. I quickly breezed through the manual the first time before my flights so i am sure i have missed a lot of details. I did notice that long after takeoff, my thrust settings are still in "TO" mode. I need to first figure out how to change them to "CLB". This weekend will be a lot of careful reading :). This sim is hard and as real as it gets, that why i am addicted to PMDG products :D. You guys are the best. I am eagerly awaiting the MD-11. Meanwhile i have a lot to learn about the Queen.

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