找到了一个官方的说法：Known Problems Within FSX
PMDG 747-400 fails to reload

FSX has a problem in the way it loads custom animations for the visual models. PMDG relies heavily on custom animations in order to do everything from flaps and slats to allowing users to de-select the winglets or open and close the cargo nose of the 747-400F. For this reason, the PMDG 747-400 is susceptible to a quirky fault within FSX that is generally relatively easy to avoid:

If you have selected a PMDG 747-400X, then re-enter the aircraft selection menu and select a PMDG 747-400X of the same engine type, you MIGHT trigger this quirky little bug in FSX, and the PMDG 747-400 will fail to load properly and be unflyable within the simulator. If this happens, simply close the sim and start over again.

We identified this failing to Microsoft but there simply wasn’t sufficient time for them to address the issue, although they were able to find the cause of the problem. Hopefully for a future update we will see a fix!

Sometimes it is not obvious that you have been bitten by this bug- so here are a few things that are SURE signs that it has happened:

* The cockpit backlighting is ON and the displays are blank
* The cockpit switches won’t animate correctly
* The visual model appears rigid and is not animated correctly
* There is smoke pouring from the engines and the model won’t animate.

This bug should rarely affect you- and can be avoided by one simple rule: Don’t reload the same engine type airplane. (You can switch between engine types with no problems.)

刚试了一下，飞完一圈儿后调入别的飞机飞一下，然后再选PMDG的飞机，貌似有时候可以消除这个问题。

上面说的二进宫的问题如果直接退出FSX再重新进入，就恢复正常了，但是还是只有第一次。