This is not something that I think is a large enough issue for PMDG to worry about when they are working to get people flying. My experience so far has been great. I have had no CTD's or frame rate issues. Bird runs great with REX, UTX, UT2, and custom airports. However sometimes on approach, when work load is getting high, I will slow down the simulation rate to slowest while I get my charts together and get the FMC programmed for approach. If the AP is engaged in any mode, the plane will roll drastically. The roll will continue until the plane enters a dive and will not recover on its own. disengaging the auto pilot the roll stops and is recoverable. I have duplicated this in LNAV, HDG, LOC, and CWS R modes. Haven't tried in APP mode, too close to the ground for that kind of fun. This does not really affect my gameplay, but I thought that if resolvable, could be worth fixing in an upcoming service pack.

HiThis is just a thought, I don't know for sure. There used to be a restriction on sim rate with autopilot use when going faster. In FS2004 it used to be limited to 8 X I think & with FSX it was increased to 16X. I'm guessing but I would say that the problem could be related to FSX & not NGX.

Definitely not an FSX problem, I've used this option before with other AC.

This may be the reason -- just guessing ! With the FSX standard aircarft, and most other addon aircraft, the dynamics of items such as the autopilot, are calculated by Microsoft routines in FSX, which knows about the Sim rate, and thus, can account for the time compression in doing calculations that depend of time, (ie delays, smoothing, time constants). The PMDG does its own far more sophisticated calculations. If these calculations are not taking into account alterable SIM Rate from X1, , then they will calculate incorrectly, and result in very unstable, or overly stable dynamics. Rather than change Sim Rates, have you tried pausing instead ? That may work for you better, if you need additional time during a time critical operation. If PMDG is not making use of "Sim Rate" in their calculations, it could be that adding that would make things overly complex and complicated, and time consuming to re-design and develop. ? NOT FOR ME TO SAY ... ask them. I really don't think one is expected to fly the PMDG 737NG at anything bit a realistic X1. All I am doing, in the absence of any other response, is offering a "very simplified" explanation of what may possibly be happening. Geoff

Geoff, I had figured that it had to do with the processes running outside FSX. The only problem with pausing is that you cannot operate all systems in the bird.