I just had a weird flight with my 737-800. It was a flight from EBBR to LEBL. At FL360 the NGX suddenly started losing speed. It fell from 260 to 210, MPC showed BUFFET ALERT and the plane started descending rapidly. I disconnected the A/P and A/T and floored it. After a brief struggle I managed to get the plane leveled and the speed climbed up a bit. I engaged A/T, but when I tried to engage A/P, it wouldn't start. There were no failures present. Also, it was almost unflyable by hand, almost like the plane is caught in a microburst. My hardware setup (X52PRO) is working flawlessly. I tried to download new weather in FSX since sometimes it helps resolve these types of problems, but it didn't help. The slightest yoke move resulted in vertical speeds ranging from +4500 or -5000 and high bank angles.
I tried the same flight again. This time, however, the speed suddenly went up from 260 to 360! Of course, I got overspeed warning. Again, I paused the FSX, downloaded new weather and it this time it worked. I applied speed brakes and let the plane slow down. For some reason it didn't disintegrate in the air since it took me at least a minute to slow down. And now, while I'm writing, the plane started losing speed again, but not too much.
So, my questions are:
1. Why didn't the A/P start after my brief struggle in the first flight? I am sure that there are some limitations when A/P will not engage. What are they?
2. I am aware that using FSX weather is not the best option and I know that losing speed and overspeed are FSX related issues. But can the weather engine in FSX be tweaked somehow so it doesn't happen again? I am not using any add-ons because my computer is not quite capable of running add-ons smoothly.
Thanks!
Jakov J.