Narrative:

Flight was a personal flight on an IFR flight plan. On taxi from parking to runway; safety pilot had connected handheld GPS device to aircraft electrical system using available socket. Low voltage light illuminated and GPS was disconnected prior to takeoff. Low voltage light flickered and went out. Amp meter indicated a discharge situation but seemed to correct itself. In the air; the low voltage light came back on and almost immediately thereafter internal cockpit lights started to flicker. Pilot was in contact with ATC throughout the flight and was in the process of informing ATC of electrical power problems when the garmin 430 (primary radio) failed and tried to re-boot. Cabin lighting was also lost at that time. Pilot shut down all electrical systems (master switch; external lights; etc.) to conserve any battery power. Both pilot and safety pilot had handheld transceivers which were stowed; but in back seat. Ultimately they were retrieved and pilot was able to make contact with tower (destination airport). Tower gave clearance to land about 10 miles north of field. On approach to airport; master switch was turned on and contact was made with tower using garmin 430 radio. Aircraft landed safely and all electrical power was lost on taxi to hangar. Lessons learned: - believe the low voltage indicator; don't take off if there is any question about efficacy of electrical system. - 'Aviate' and navigate; then communicate. - Have flashlights and handheld transceiver immediately available to limit inability to 'aviate' and other distractions. - Ensure handheld transceiver is fully powered (safety pilot's unit was not powering up and had to switch to pilot's unit).

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Original NASA ASRS Text

Title: A C172 low voltage light illuminated before takeoff but the pilots continued anyway. Enroute the aircraft lost all electrical power but the pilot had hand held radio to talk with ATC on.

Narrative: Flight was a personal flight on an IFR flight plan. On taxi from parking to runway; Safety Pilot had connected handheld GPS device to aircraft electrical system using available socket. Low voltage light illuminated and GPS was disconnected prior to takeoff. Low voltage light flickered and went out. Amp meter indicated a discharge situation but seemed to correct itself. In the air; the low voltage light came back on and almost immediately thereafter internal cockpit lights started to flicker. Pilot was in contact with ATC throughout the flight and was in the process of informing ATC of electrical power problems when the Garmin 430 (primary radio) failed and tried to re-boot. Cabin lighting was also lost at that time. Pilot shut down all electrical systems (master switch; external lights; etc.) to conserve any battery power. Both Pilot and Safety Pilot had handheld transceivers which were stowed; but in back seat. Ultimately they were retrieved and Pilot was able to make contact with tower (destination airport). Tower gave clearance to land about 10 miles north of field. On approach to airport; master switch was turned on and contact was made with Tower using Garmin 430 radio. Aircraft landed safely and all electrical power was lost on taxi to hangar. Lessons Learned: - Believe the low voltage indicator; don't take off if there is any question about efficacy of electrical system. - 'Aviate' and navigate; then communicate. - Have flashlights and handheld transceiver immediately available to limit inability to 'aviate' and other distractions. - Ensure handheld transceiver is fully powered (safety pilot's unit was not powering up and had to switch to pilot's unit).

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.