Date: 202104
Local time of day: 1201-1800
Location: ZZZ.TRACON, US
Flight conditions: IMC
Weather elements / visibility: Cloudy; Turbulence; 10
Light: Daylight
Aircraft: M-20 F Executive 21
Operator: Personal
Operating under: Part 91
Flight plan: IFR
Mission: Personal
Flight phase: Descent; Cruise
Airspace: Class E ZZZ
ATC / advisory: TRACON ZZZ
Aircraft component: AC Generator/Alternator
Component problem: Malfunctioning
Reporter organization: Personal
Reporter function: Instructor; Pilot Flying
Reporter qualification: Flight Crew Instrument; Flight Crew Flight Instructor; Flight Crew Air Transport Pilot (ATP); Flight Crew Multiengine
Human factors: Troubleshooting; Communication Breakdown
Anomaly: Aircraft Equipment Problem Critical; Deviation / Discrepancy - Procedural Published Material / Policy
Detector: Person Flight Crew
When detected: In-flight
Result: Air Traffic Control Provided Assistance; Flight Crew Diverted; Flight Crew Overcame Equipment Problem; Flight Crew Requested ATC Assistance / Clarification; Flight Crew Landed in Emergency Condition; General Flight Cancelled / Delayed; General Maintenance Action
Contributing factors: Aircraft
Primary problem: Aircraft

Narrative: While on an IFR Flight from ZZZ to ZZZ1 in cruise flight in IMC conditions; the aircraft experienced a total loss of electrical power. Aircraft was being piloted by a Private Pilot receiving instrument instruction from me. The STEC 60 autopilot was engaged and managing the both navigation and altitude control. When the electrical failure occurred; the autopilot disengaged and aircraft began a descending turn that was recognized by the avionics powering down and the airspeed starting to increase. As the Instructor; I announced that I had the controls and initiated partial panel IMC operations. Focusing on the principals of Aviate; Navigate and Communicate; I began controlling the airspeed to maintain level flight and shallowed the angle of bank until I achieved what appeared to be level flight after approximately 150 degrees of heading change.The Pilot (Instrument Student) asked if he should get the iPad and the AHRS up from ForeFlight which I agreed was the right next step. We confirmed that we were in level flight and executed a shallow bank to reestablish the desired easterly course using the partial panel information and continued to backup with ForeFlight. Next; I called for the pilot to turn off the Master switch and then turn it back on to reestablish the main power. Then I called for him to activate the Avionics Master switch which reestablished all of the avionics. The alternator was not restored so we shed the electrical load and choose not to change anything else since we had the flight instruments and the communications/transponder operational. We confirmed that all of circuit breakers were in and none were popped.We were able to update ATC on the situation and we entered VMC conditions after about 5 minutes. All systems were operational except the alternator. We worked with ATC to change the clearance to ZZZ2 for support and did not feel that we needed emergency equipment when they asked. I also asked for a phone number to ZZZ3 Center for ATC in case we lost communication or electrical again. The weather at ZZZ2 was:[Date] XA:53 METAR ZZZ2 [Date]XA53Z 20008KT 10SM OVC032 11/07 A2988 [Date] XA:53 METAR ZZZ2 [Date]XA53Z 19006KT 10SM FEW022 SCT036 OVC044 12/07 A2987 We maintained visual flight control for the rest of the flight to ZZZ2 in case we lost electrical again. We had been cleared direct to ZZZZZ for the approach to Runway XX. We did lose electrical/communication again due to the battery discharging just before we arrived at ZZZ1. We called ZZZ3 Center on the cell phone; they helped manage us and gave us a phone number to the ZZZ2 Tower. We advised ZZZ2 we had the field in sight and asked for clearance to land. The rest of the flight was uneventful and ATC gave us progressive instructions to the FBO via the cell phone. At the FBO; the I removed the cowling; visually inspected the major electrical components and verified that there were no loose wires or indicated damage to the components. Maintenance was called but none was readily available and no one seemed to have a 12V Auxiliary Power Unit. I powered up the aircraft to see if all of the systems would come back online - all systems came back online including the alternator. An assessment was made that all systems were operational and the next two legs of the flight would be performed in Visual Flight Conditions. Additional Info: The aircraft was just purchased and was being flown by the new owner and the instructor back from ZZZ4 to ZZZ5. The pre-buy inspection had been completed the week prior at a Mooney Service Center in [name removed] State. There were no known or observed issues with the electrical system. ATC was outstanding in their assistance; handling and communication.




Synopsis: Flight Instructor reported that the loss of all electrical power resulted in a diversion; and a precautionary emergency landing.