As the title of the topic indicates, after an initial normal flight with vers 1.0, I upgraded to vers. 1.1 and immediately after the oxygen check, my background "wind/AC sound" changes to an ugly sound reminiscent of a prop. Every time I initiate a flight, the sound is normal when the APU comes on, it is only after a few more minutes that it goes bad. Anybody else experiencing this, and what would be the cure?Thank you.Jean-Claude

Reason found. For some unknown factor, my radio nav receiver squelch after a few minutes (and without my intervention) start to be full blast. Hance this sound. Problem solved.