Actually I already have Audacity and I know you can do lots of cool stuff like adding effects and so on but what you mean is to simply replace the origional sound files with new ones containing your own sounds?
If taking that approach couldn't I use almost any application capable of saving wav files?
One other thing, if my memory serves me the original boarding and deboarding sounds are different depending if you're in the cockpit or in external view. Does that mean there's both internal and external sound sets?
Well, guess I'll have a look at it myself tomorrow. Must admit it would be cool if I was able to come up with my own custom sounds and especially if they are from real life! I do have ESSA only some 15 minutes drive from where I live so that wouldn't be a problem. Not sure though what sounds I would record that would suite as realistic boarding and deboarding sounds without actually board an aircraft since I need a flight attendant welcoming people aboard