Alternator offline. Both front and rear
 

On a flight from KAKH to Ocean City MD about 2 hours in, both alternator's went offline. She'd power till landing, put gear down early on to ensure it would work. Anyhow, what is interesting is that on landing both came back online, again. Not sure what could cause this.

Flying back Monday, had a mechanic look things over, but no apparent issues. Looking for ideas to look at.

Thanks for any help!

There was this one time
 

I had my alternators go offline once with a small pop over the headsets. rest, then never again.

What I subsequently discovered was the regulators get their reference from the bus. But, the voltage drop across 50 year old alternator switches and master would allow the regulator jump to high and shutoff.

I was measuring 1+volts across the switch contacts.

My high tech solution was, pop the switches out, still wired in, and soak the suckers 'through' the switchs to get the contacts cleaned with corrosion X, then turn switches on and off about 800 thousand times.

Voltage drop became negligible, been fine ever since.