Originally Posted by
B2N2
Turn off then turn on the transponder, while waiting to recycle check for a possible electrical issue. Ammeter or volt indicator.
Check circuit breaker. Reset after appropriate cooling down period.
Call ATC and request to proceed without transponder. If denied climb or descent out of said Airspace.
That was exactly what I did. When I checked the ammeter it was indicating a discharge so I told ATC that I had lost my charging system but as I was only 30 minutes from home I would reduce my electrical load and continue. If I lost comms I would phone him on my cel. ATC was OK with that and the radio was fine all the way
The alternator had failed due to a broken wire. The engineer figured that the wire was broken when the cowl was replaced after the mag repair.
So overall not a very big deal but there are a few take aways
1) The older style transponders with a cavity tube like the King KT76, Cessna 300, and Narco AT50 are very sensitive to voltage so they will be the first thing to fail after a charging system failure.
2) Early recognition of the failure gave me plenty of time to deal with it. If I had not checked the a ammeter I probably would have had the radio die just as I was entering the very busy control zone of my destination airport
3) I have terminal and my home base tower phone numbers saved in my cel phone
4) It is a good idea to be extra alert on the first flight after significant maintenance as other problems may have been inadvertently introduced