Little "whistles" in c172?

So when the avionics are powered on (even with the engine off), I hear what I can only describe as an occasional very quick whistle sound. Like - very shot, higher pitched whistle that lasts like 1/2 of a second. It happens maybe randomly? Every several seconds or so? It’s also pretty faint volume wise.

It “feel” like this is something being simulated (like it’s supposed to be there). But what on earth is that?

Voltage. Circuits coming to life. Have you ever listened to your graphics card? And no, I am not talking of its fan. :stuck_out_tongue_winking_eye:

It would be cool is if they simulated the sound of the avionics fans for avionics bus 1 and 2. Something we check during pre-flight.

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Huh, ok. I didn’t mean the sound happens at the moment when I turn on avionics, it’s pretty much always happening, several times a minute. I meant to say that it only happens when the avionics are on. It does seem to be electronics related though since it only happens when they’re on. Strange.

Is it wind?

It may be the turn coordinator gyro spooling up

Morse ID from a navaid?

Yeah, I’m not sure. Maybe I’m crazy (especially if no one else hears it lol). It’s not a one time thing (like something spinning up). It happens maybe 15 - 20 times per minute, as long as the avionics are powered up.

It basically sounds like this: https://voca.ro/1gXIEKBq4yjS (volume is pretty low though).

Is any NAV, ADF or DME audio receiver turned on? If yes, deselect it.

couldn’t reproduce what you heard. funny thing is when I tried to test, it ended up being a 2.5 hour scenic flight haha.

OK! It is the radio :slight_smile: If I switch to com2, it goes away. It also goes away if I turn down the volume on com1. Thanks for the ideas all. It doesn’t bother me, it was more of a “hey, what the heck is that!?” sort of thing.

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