Jet engine sound

Hi all,
I've had this sound related problem for a while and never found out what's causing it.
It's louder on external view, what I'm getting is the sound of a jet engine running whether or not they are and even with no ither
Aircraft there.
I have thought of changing sound files in an attempt to find out what's calling the sound file being played.
Before I do that, does anybody know right away what it could be especially if they have had same problem, does not happen when have prop aircraft loaded.
Fsx is fsx gold version.
Regards
Steve
I've had this sound related problem for a while and never found out what's causing it.
It's louder on external view, what I'm getting is the sound of a jet engine running whether or not they are and even with no ither
Aircraft there.
I have thought of changing sound files in an attempt to find out what's calling the sound file being played.
Before I do that, does anybody know right away what it could be especially if they have had same problem, does not happen when have prop aircraft loaded.
Fsx is fsx gold version.
Regards
Steve