Small Aircraft
Flight Crew Commercial; Flight Crew Multiengine; Flight Crew Instrument; Flight Crew Flight Instructor
Flight Crew Last 90 Days 120; Flight Crew Total 2200; Flight Crew Type 1591
Confusion; Troubleshooting; Workload; Communication Breakdown
Aircraft Equipment Problem Less Severe
Flight Crew Diverted; Flight Crew Landed in Emergency Condition
Aircraft; Human Factors; Environment - Non Weather Related
During dual flight with Instrument student; we had a total electric/avionics failure.  The failure we suspect stems from a short in the right seat's headset jacks (possibly due to the Push-to-talk).  There was loud static sound on the intercom; exacerbated when trying to adjust right seat's headset jacks.  Soon after leaving hold at ZZZZZ; on vector 360 at 3;000 feet; Com1 flashed and went dark.  Student set approach frequency in Com2.  Then Com2 went dark also. When student was about to squawk 7600; transponder turned off. Then GPS and entire Avionics Stack turned off. Ammeter appeared to be stable zero. We checked circuit breakers; none popped.  Com 1; Com 2; Transponder flashed on and off intermittent.  Tried to restart Transponder; it read Transponder failure when on.  Turned Avionics Master off and on. Still on vector 360; I decided to continue VFR straight ahead to ZZZ and descended to be 500 feet below broken cloud layer. We could hear ATC trying to contact us; even when the entire stack was dark. Both the Student and I tried transmitting that we had full electrical failure and going to ZZZ; with no recognition.  We circled to enter 45 to the left downwind XX; with extreme caution scanning for traffic.  At that moment I decided to take my headset jacks out.  When I did; Com1; 2; and transponder turned on.  I'm trying to communicate vocally with Student in loud cockpit.  I tell him to tell ATC we are landing at ZZZ.  I dial in CTAF on standby.  I tell student to announce our position. Windsock Shows direct crosswind. Abeam the numbers I see an aircraft departing Runway XY.  I point out the aircraft and tell student to turn right; to depart the pattern.  With no indication that he understood; I yell and gesture 'My Controls.' Turn right to the East then South and see the other aircraft turning right downwind XY. I turn left to reenter 45 to the right downwind; cautiously scanning for traffic. Reenter pattern right downwind XY. I give controls back to student. Student lands.  We are greeted at the FBO by 2 staff members.  I learned that my student was successful on last transmission with ATC.  They inform us that they called ATC back when we were on the ground.  Student called national hotline to close the flight plan.  After a moment to reflect; I did not try removing the Push-to-talk; and reinserting my headphones.  So the malfunction could have been due to the Push-to-talk.  After reflection on the difficulty of vocal communication; I realized that I was wearing a mask due to COVID-19.  When I was trying to communication the student could not see my lips moving and my voice was muffled; which probably led to the student's confusion.  My reason for diverting to ZZZ; was because ZZZ1 is frequented by corporate jets and many GA aircraft; to avoid high traffic and interference. And because when we couldn't figure out what had happened; we were just to the south of ZZZ and landing was the priority.
Flight Instructor reported experiencing an electrical and avionics failure while conducting a training flight. While attempting to speak to the student without using a headset; the instructor noted it was difficult to communicate because the COVID-19 mask muffled the voice.