Alex,

Thanks for your reply.
I made some more long flights and few short flights. Majority of time I am still getting flashing,
I have sufficient Video memory in  my systems. FSX high settings with 707 ,still 1485MB memory available. GTX480

ACE is not working. I am keep checking  Flight Deck only and  clicking save, it goes gray, but my check mark disappears. Still Exterior attached to 707.

Some flights flashing disappears, I enjoy the flight. Most of the days it is back. :(
BTW, Doppler and INS are working perfect
If I am an  only member is experiencing with this problem. Then forget it. You do it when you have a spare time. :'(
Sanal