Hello

 

I need some help, i got a hard time with the autopilot of my pmdg planes both 737 and 777, I take off and after 10 - 15 min flight i got this

 

1. The plane will start to loose altitude and gain speed. In this case the CMD A, VNAV and

LNAV lights remain lit. I will occassionally get a Yellow Caution warning. 

 

2. With the CMD A, LNAV and VNAV light still on the aircraft will reach a point where the

aircraft will ignore a waypoint and just keep tracking on the last course. Any attempt to

disengage the autopilot and steer the aircraft back to the FMC fails. deviate from the FMC

Flight path.

 

3. With the CMD A, LNAV and VNAV light still on and on a long straight FMC path the aircraft

will slowly deviate from the FMC path so that at the next waypoint the aircraft is miles

from the intend position.

 

In both the last two cases the aircraft will have flown some portion of the FMC path but

then with no warning the aircraft will deviate as stated above.

As I stated above, I cannnot get the Autopilot to reaquire the FMC Flight path. I attempt to

steer the aircraft back toward the next waypoint or updating the FMC to put a waypoint out

in front of me but when I reengage the autopilot the aircraft will not reaquire the FMC Path.

 

I got fsiupc but neber really use it, i dont have fs2crew.

 

Do you have any suggestion

 

Look in the Legs page and make sure you have no discontinuities. Somewhere you got off course and you did not see it immediately. You miss a waypoint because of a discontinuity and the aircraft will just continue forward. It probably won't allow you to get on course because the waypoint is behind you. You have to go to the FMC Legs page and look at what is the next waypoint showing on the flight display. Look for it in the FMC Legs page and then hit the LSK next to the waypoint and then the top left LSK and then activate it. You can now hit the LNAV/VNAV and you should be back on course (but ONLY if your aircraft is heading in the direction of the next waypoint). I see that you tried that but you still need to be pointed in the right direction.  To get pointed in the right direction, hit Hdg and steer it toward the next waypoint then hit the LNAV.  Once you are on  the glideslope, hit the APP and the flight will follow the glideslope to the runway (if NAV1 shows the proper NAV setting). It's rather simply really!  :lol:

Best regards,

Thanks for your answer

 

but I wish that it was that simple, there is no discontinuity, i know when there is one. Even when i fly point to point with not using the fmc, the autopilot obey the orders but at a certain point it doesnt follow anymore speed, cap, vertical speed, altitude it refuses to follow even if it is engaged;

 

Go on youtube type "autopilot unreposiveness pmdg", in that video you will see what i talking about. 

 

 or better this link

 

http://forum.avsim.net/topic/389902-semi-unresponsive-plane/%C2'>

Here is his video. You might want to post this in the PMDG forum.

 

I resolved my problem. the battery on my mothercard was weak, since 3 weak i have to put the clock back on time several time, when that battery is weak it brings some problem to the bios too. I changed that battery his afternoon since then no more problem the autopilot do whay i want, and it follows my waypoint, beware if the battery of your mothercard get weak, your pmdg autopilot will cause you alot of troubles.