... but I'm looking for more detail on what specifically on the Audio Panel works and doesn't... e.g. it's not clear from the Supplement whether the Intercom continues to work or not.
For us old-timey steam-gauge types with the 340 audio panel, the intercom should work because:
1. The intercom is entirely driven by the 340
2. There is only one power lead to the 340, so it has no way to detect whether it's on essential bus or not.
Marker beacons (as useless as they have now become) should also work for the same reason.
Anything that depends on an external module that is NOT powered by the ess. bus (such as nav/com 2) won't work.
I suspect it's the same for the G1000 planes, also. For the same reasons.
waynemcc999 wrote:Thx, Ben. Just what I was looking for. I've been reluctant during flight to turn Master Off and Essential Bus On.
No problem. Actually you don't even have to turn off the master switch. Hitting the ESS bus will disconnect all of the other stuff anyway. If you don't want to try it in flight, then give it a try while on the ground
Mystery solved. The audio panel isn't ON the essential bus at all. But it has a no-power mode that lets the pilot use Nav/Comm1 when there is no power to the audio panel. It just becomes a passive device between the two.