Dear Members of the AVSIM/PMDG Support Forum,I am in need of help, for my PMDG 747-400 looses power in mid-flight, usually once I hit my cruising altitude (around FL330, FL340). I am able to fly steady at my cruising altitude for a little bit, but after a while, my airspeed begins to slowly decrease. Once it hits 230KIAS, she dangerously begins to turn left and right and I loose altitude -- in the end, I stall. I also loose my VNAV, my speed switches to FLCH, etc. If anyone has a fix for this aircraft, please send me it. This is a wonderful aircraft and I don't want this to ruin my experience with it.Thanks.Connor LevensPresident and CEO of [email protected]

First, you have the AT engaged? Right? Next, what's your thrust level in cruise. Now compare that to your EICAS thrust limit? What you are looking for here is this: Thrust should never touch the EICAS thrust limit in cruise. If you have the AT engaged, this is almost certainly what's happening. The airplane needs a bit more thrust and the EICAS Thrust Limit function is well, limiting.Why might this happen? Check out your Vnav page and make sure you are at the OPT altitude. At MAX you are hanging by a thread. Don't go there unless you must for some emergency. Next bump up EICAS thrust limit to CLB. That will give the AT a bit more elbow room if it needed it.(Ahh just like the old days . . . I think those tutorals really helped.)

Couple things to check:1. Make sure the two boxes under Controls Override are NOT checked in the PMDG Options menu. If they are, this problem is almost certainly being cause by the position of your physical throttle interfering with the A/T...2. What kind of weight are you taking off with. Check the FMC VNAV CRUZ page and make sure you aren't trying to exceed the maximum cruise altitude or something close to it. You want to fly at the Optimum altitude or slightly below, then step climb according to the FMC schedule as you burn off fuel if the flight is long enough... (if the flight isn't long enough to generate S/C points on the route, you're carrying way too much fuel anyway.)

This is a weird issue which is popping up on the forum on a regular basis. I have experienced it once -that was before the 744F update-, exactly the same way Connor Levens describes.Very heavy plane (YSSY-FAJS) loaded with +250.000lbs of fuel, and about 30 minutes after top of climb, slow speed decrease untill stall. Everything was OK on the plane configuration.I thought by then that could have been a FMC coding issue, since the VNAV page was claiming max FL was 340, when I think it should had not exceed FL310 (given the TOW that day).The speed/power loss occured when I was at FL340.And I was flying with FS default weather engine.

Have another quick look. Thrust should never touch the EICAS thrust limit in cruise. If it ever does, a slowdown and then stall (just as described here) will occur. Part of the max altitude calculation will use full, EICAS CRZ limit thrust. It there is the slightest hickup (or maybe even sim > airplane interface mismatch), thrust will not be able to adjust upward and you'll start to slow down. In this case, bump EICAS limit up to CLB. It's what a RW pilot might do too. To monitor this situation in the future, watch thrust like a hawk. The airplane's working fine. And of course like Matts said, make sure that you don't have your joy sticks interfering with the airplane's autopilot. BYW, Why is this blue?!!