I'm having the strangest problem now. I can ask ATC for an ALT change but get no response. They just ignore me and continue on with everything else as usual. If I don't fly to the clearing Altitude, ATC will just nag me for the rest of the flight without canceling my flight plane. What in the world is going on??? :-hmmm

Yes, I've had that problem recently.I think it must be some combination of circumstances such as:Setting your flightplan cruise to FL300, then going up to FL320 (say to avoid another aircraft) and then wanting to go back to FL300.Or setting your flightplan cruise to FL360, then finding that your FMC says FL320 is the optimum, so that you are trying to reduce from an altitude you haven't reached yet, or something like that, may be to do with what altitude you have been cleared to. There is some combination of flight level changes ATC can't handle I think.Does any of that ring a bell?The only way around it I've found is: 1)make a note of your next waypoint, 2)go go back into FS Flight Planner and reload your flightplan,3)edit cruise altitude to the one you want, 4)delete all waypoints occurring BEFORE the one you are approaching (except for your departure airport), 5)save the edited plan under a new name (temp.pln will do)6)say "No" when asked if you want to relocate your aircraft,7)return to your flight and request a new IFR destinationYou'll then have to climb or descend to the altitude you set and everything should be OK. You'll probably also be told to make a course correction (because FS now thinks you flying direct from departure airport to next waypoint, rather than via your old flightplan), but provided you are pretty close to the next waypoint, the deviation is small and you can probably ignore that. This is a bit longwinded (not as bad as it sounds, 2 or 3 minutes?), but better than losing half a flight across the Atlantic or something!

I think it started after the fs9.1 patch. Usually I am in fact following fmc recommended current altitude (lower than fp cruise).Usually I do EVENTUALLY get cleared to my current lower altitude though.regards,MarkXPHomeSP2/FS9.1/3.2HT/1GIG/X700pro256

Ailchim your post is right on the money as to what I've been seeing on my system, thanks for the post. I too wonder did this start with the FS9.1 patch. Thanks guys for the feedback...