Two C180 pilots report complete electrical failure after avionics repairs were performed on the airc...

Narrative:

There had been a radio upgrade performed recently (installation of a garmin 430W and a garmin 696). After the upgrade the autopilot showed a fault so the avionics shop (avionics shop #1) sent it out to avionics shop #2 for repair. After a sending the components back and forth a couple of times; without a favorable outcome; it was decided to take the aircraft up to avionics shop #2 for repair. It was determined that there was a broken wire; in a harness behind the panel; which avionics shop #2 said they had repaired. After a through preflight and autopilot ground check we took off. We had set the autopilot for climb in the heading mode (assigned heading) then over to navigation mode once we were told to go direct. We then noticed the autopilot did not capture the course; the autopilots lights dimmed; so we disconnected the autopilot. Sometime after leveling off we lost the radio and then progressively lost all electrics. We were on top of a broken overcast so we squawked 7600 and proceeded to diagnose the problem. The alternator circuit breaker had popped. We turned off the alternator master; reset the circuit breaker; waited a few minutes; and then turned the master back on. It again popped with in a few seconds. We turned off all non essential electrical to conserve power. We had hand held radio that would not allow us to transmit so we monitored 121.5. We continued and proceeded on the assigned course and altitude. We had a garmin 696 (this unit has its own power supply) that was cross programmed with the garmin 430W. We proceeded as assigned until we thought we had a good opening to descend and proceeded to our destination. The transponder appeared to be operating until we were approximately 6-10 miles south of our destination. We over flew our destination's airspace at 3;000. Determined the active runway and started our descent into the traffic pattern. At 2;500 MSL we received a green light for landing. Once established on a downwind we again received the steady green light for landing. Once off the runway the tower gave the signal to proceed to taxi. The following day it was determined by local maintenance that a direct short in a wiring harness had caused the problem and was repaired.

Original NASA ASRS Text

Title: Two C180 pilots report complete electrical failure after avionics repairs were performed on the aircraft. Reporters continued on their IFR flight plan in VMC and landed at their destination with a green light from the Tower.

Narrative: There had been a radio upgrade performed recently (installation of a Garmin 430W and a Garmin 696). After the upgrade the autopilot showed a fault so the avionics shop (Avionics Shop #1) sent it out to Avionics Shop #2 for repair. After a sending the components back and forth a couple of times; without a favorable outcome; it was decided to take the aircraft up to Avionics Shop #2 for repair. It was determined that there was a broken wire; in a harness behind the panel; which Avionics Shop #2 said they had repaired. After a through preflight and autopilot ground check we took off. We had set the autopilot for climb in the heading mode (assigned heading) then over to NAV mode once we were told to go direct. We then noticed the autopilot did not capture the course; the autopilots lights dimmed; so we disconnected the autopilot. Sometime after leveling off we lost the radio and then progressively lost all electrics. We were on top of a broken overcast so we squawked 7600 and proceeded to diagnose the problem. The alternator circuit breaker had popped. We turned off the alternator master; reset the circuit breaker; waited a few minutes; and then turned the master back on. It again popped with in a few seconds. We turned off all non essential electrical to conserve power. We had hand held radio that would not allow us to transmit so we monitored 121.5. We continued and proceeded on the assigned course and altitude. We had a Garmin 696 (this unit has its own power supply) that was cross programmed with the Garmin 430W. We proceeded as assigned until we thought we had a good opening to descend and proceeded to our destination. The transponder appeared to be operating until we were approximately 6-10 miles south of our destination. We over flew our destination's airspace at 3;000. Determined the active runway and started our descent into the traffic pattern. At 2;500 MSL we received a green light for landing. Once established on a downwind we again received the steady green light for landing. Once off the runway the Tower gave the signal to proceed to taxi. The following day it was determined by Local Maintenance that a direct short in a wiring harness had caused the problem and was repaired.

Data retrieved from NASA's ASRS site as of April 2012 and automatically converted to unabbreviated mixed upper/lowercase text. This report is for informational purposes with no guarantee of accuracy. See NASA's ASRS site for official report.

Attributes
ACN	902551
Time
Date	201008
Local Time Of Day	1201-1800
Place
Locale Reference	ZZZ.TRACON
State Reference	US
Environment
Flight Conditions	Mixed
Light	Daylight
Aircraft 1
Make Model Name	Cessna 180 Skywagon
Operating Under FAR Part	Part 91
Flight Phase	Cruise
Flight Plan	IFR
Component
Aircraft Component	Electrical Wiring & Connectors
Person 1
Function	Pilot Not Flying
Qualification	Flight Crew Commercial Flight Crew Flight Instructor Flight Crew Multiengine Flight Crew Instrument
Experience	Flight Crew Last 90 Days 120 Flight Crew Total 2350 Flight Crew Type 500
Person 2
Function	Pilot Flying
Qualification	Flight Crew Private
Experience	Flight Crew Last 90 Days 50 Flight Crew Total 550 Flight Crew Type 220
Events
Anomaly	Aircraft Equipment Problem Critical

Two C180 pilots report complete electrical failure after avionics repairs were performed on the aircraft. Reporters continued on their IFR flight plan in VMC and landed at their destination with a green light from the tower.