Static with some Acft.

I have the Fokker 70/100 and Milton Shupes -7 in FS2002 and have had no problems. When I install these two planes in FS9 however, I often (not always) get a lot of static when I fly them. Sometimes it is so loud that it drowns out the engine noise. Seems to happen mostly when changing to tower or spot views. At other times it doesn't happen at all. Any clue as to what's happening here. I always fly using headphones and when the static occurs, I can't get them off fast enough - really loud. Thanks for any help.Jim