Question about when to contact ATC for clearance if avionics are turned on after engine start in the Bonanza

[toby23]

I just completed my first flight in the Turbo Bonanza and when I heard the sound change when the seals inflate - mind blown...

One thing I am unsure about, not being a real pilot, is when you would contact ATC for clearance if the avionics don't go on until after engine start (per checklist).

Thanks for any real world advice.
Toby

[SadBucket]

I generally ask after my run up irl. obviously I'd get taxi clearance to a place to runup if needed.

[toby23]

Thank you SadBucket. That sounds like the procedure at a small GA airport? What about at a larger airport? Would the avionics ever be turned on for clearance and then off again before engine start?

[SadBucket]

@toby23 I do this at halifax international. you generally never run avionics with the engine off in small piston aircraft (without external power and even then that's usually for trouble shooting)

[toby23]

Thanks for confirming. Appreciate your help.

[Woolies]

Interesting. What if you need startup clearance? Guess different rules in US?