Jonathan Alvord
Well Known Member
Went for fuel filling trip today and lost all avionics including transponder, EIS, GRT displays. Thankfully had steam gauges for backup. That is the short and sweet. Here comes all the details leading up to it. The plane has roughly 460 hours on it and I am the second owner. Two months ago we replaced the alternator when the displays turn off when coming in to land. No real issues otherwise up until today. Run up normal, flew to Oregon for gas and avionics shut down while on final and rebooted. Filled up, run up good, Voltage 12.9 amps 10 I believe all in the green on the EIS and displays. Half way back in VFR all the avionics turned off, no contact with ATC and I was on flight following, called Flight services on cell to ask them to relay to ATC that I had lost comms and would continue VFR direct to my local airport.
Now why did it fail? It appears the PTT on joystick was pulling power from the avionics, that's my theory. I and two others have looked through the plane most of the day. All the solenoids in the engine compartment appear to working. WE have power at the master switch, we no longer have power to Avionics (GRT, Radio stack) and Fuel pump. I have checked all the fuses and can't find a single one that is bad. We were able to jump the power to the avionics and it still works , just not from the switch. When testing the panel for endurance fuses (fuel pump, manifold pressure, avionics, EIS, and inst lights) we could only get 2.7v, All of the Main fuses were working (nave lights, auto pilot, pitot, strobe, trim ignition, trim switch, landing, pwr source 1, interestingly Power source 2 had no fuse in it).
I am unable to find a wiring diagram, although I know it would help we drew out one and I have a picture but can't post here. I did not pull the floor panels off and have had no problems with the fuel pump in previous 250 hours.
Any ideas? There are no mech or avionic specialist at the airport, this is new territory for me as to how to get it repaired. Any Advice would be greatly appreciated. BTW I am near Yakima/Tri Cities Washington.
Now why did it fail? It appears the PTT on joystick was pulling power from the avionics, that's my theory. I and two others have looked through the plane most of the day. All the solenoids in the engine compartment appear to working. WE have power at the master switch, we no longer have power to Avionics (GRT, Radio stack) and Fuel pump. I have checked all the fuses and can't find a single one that is bad. We were able to jump the power to the avionics and it still works , just not from the switch. When testing the panel for endurance fuses (fuel pump, manifold pressure, avionics, EIS, and inst lights) we could only get 2.7v, All of the Main fuses were working (nave lights, auto pilot, pitot, strobe, trim ignition, trim switch, landing, pwr source 1, interestingly Power source 2 had no fuse in it).
I am unable to find a wiring diagram, although I know it would help we drew out one and I have a picture but can't post here. I did not pull the floor panels off and have had no problems with the fuel pump in previous 250 hours.
Any ideas? There are no mech or avionic specialist at the airport, this is new territory for me as to how to get it repaired. Any Advice would be greatly appreciated. BTW I am near Yakima/Tri Cities Washington.