PA-23-250 Aztec
Flight Crew Instrument; Flight Crew Commercial; Flight Crew Flight Instructor
Flight Crew Last 90 Days 13; Flight Crew Total 255; Flight Crew Type 5
Aircraft Equipment Problem Critical
Flight Crew Inflight Shutdown; Flight Crew Returned To Departure Airport
Aircraft
After completing maneuvers in the practice area; we went to shoot the RNAV Runway XX into ZZZ. This approach was done under the hood with the left engine throttle closed for a simulated engine out approach. This approach was done successfully with a few touch and goes done afterwards. After completing the touch and goes we contacted approach; and went back to the Practice Area. After the engines warmed up to ideal operating temperature; due to the warmer weather we decided we were going to shut down the right engine entirely and feather the engine. Pulling the mixture to idle cutoff; and prop lever to feather; we did just that. After 1-2 minutes we tried to restart the engine. After running the checklist the engine prop turned over a few times but did nothing more. As the prop was turning over the electrical system stopped working and we had no avionics; nor could my instructor and I hear each other in our headsets. We tried to start the engine several more times; but the prop wouldn't turn over; as the battery wasn't charging and what we assumed at the time; the electrical system had failed. We then squawked 7600; ran the engine failure checklist; and my instructor contacted Tower over his phone; for clearance back into the airport; and from there we squawked 7700. On the final approach my instructor and I could talk to each other once again; but after running the descent before landing checklist and turning on the left fuel pump; my instructor and I no longer could hear each other as the electrical system seemed to be overloaded. After landing; around 5-7 minutes our avionics came back on; and we could then talk to the controllers and was able to taxi back to the parking area of the flight school. During the incident the weather was clear; winds were calm; and pressure was roughly 30.35 inches.
PA-23 flight instructor reported electrical failure inflight.