Narrative:

Departed franklin, va en route to birmingham, al. Picked up clearance with ZDC. Approximately 1 hour into the flight the left alternator inoperative light came on. Upon 3 attempts to reset circuit breaker (1-PUSH lt volt regulator C/B back in, popped out. 2-TURN lt half of master switch off, reset lt volt regulation C/B master switch on, popped out. 3-WAITED 30 min and tried #2 again, popped out). I contacted greensboro approach and notified them of my situation. Upon each change I notified each controller of my situation. During this time I had shredded down to 1 communication, 1 navigation and compass system and transponder. At approximately 1 hour and 45 min into the flight the right alternator amp reading went to 0, but no altitude failure light came on. Upon assessing the situation atlanta center notified me that my transponder signal was lost and that I was a primary target. As each minute passed the radio signal got weaker. I requested from center the nearest airport. After several attempts I understood that there was an airport 15 mi away on a heading to 270, which was blairsville, GA airport. Another aircraft was transmitting to me the phone # to call after landing. Center had told this other aircraft that he (center) was working an emergency. (I had not requested nor confirmed that I was an emergency.) I notified center that I had blairsville in sight and had begun my descent. After landing I called atlanta center and told him that we were on the ground. After several more questions he told me nothing further was needed. After losing the left alternator I felt that being good VFR and continuing the flight was safe. Alternator output on the right side was good, 20 amps. At 1 hour 45 min I turned on the fuel boost pumps to change tanks. It was at this time the right alternator amps went to 0 and no warning light came on. It was at this time that the best thing was to land as soon as possible while there was still daylight. The cause of the failure was left voltage regulator and alternator were both bad and had failed. There has been no determination as to why my right side went off line but yet showed no emergency light.

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Original NASA ASRS Text

Title: GA SMT CPR ACFT LOST BOTH ALTERNATORS AT CRUISE ALT. DIVERTED TO ALTERNATE.

Narrative: DEPARTED FRANKLIN, VA ENRTE TO BIRMINGHAM, AL. PICKED UP CLRNC WITH ZDC. APPROX 1 HR INTO THE FLT THE LEFT ALTERNATOR INOP LIGHT CAME ON. UPON 3 ATTEMPTS TO RESET CIRCUIT BREAKER (1-PUSH LT VOLT REGULATOR C/B BACK IN, POPPED OUT. 2-TURN LT HALF OF MASTER SWITCH OFF, RESET LT VOLT REG C/B MASTER SWITCH ON, POPPED OUT. 3-WAITED 30 MIN AND TRIED #2 AGAIN, POPPED OUT). I CONTACTED GREENSBORO APCH AND NOTIFIED THEM OF MY SITUATION. UPON EACH CHANGE I NOTIFIED EACH CTLR OF MY SITUATION. DURING THIS TIME I HAD SHREDDED DOWN TO 1 COM, 1 NAV AND COMPASS SYSTEM AND XPONDER. AT APPROX 1 HR AND 45 MIN INTO THE FLT THE RIGHT ALTERNATOR AMP READING WENT TO 0, BUT NO ALT FAILURE LIGHT CAME ON. UPON ASSESSING THE SITUATION ATLANTA CENTER NOTIFIED ME THAT MY XPONDER SIGNAL WAS LOST AND THAT I WAS A PRIMARY TARGET. AS EACH MINUTE PASSED THE RADIO SIGNAL GOT WEAKER. I REQUESTED FROM CENTER THE NEAREST ARPT. AFTER SEVERAL ATTEMPTS I UNDERSTOOD THAT THERE WAS AN ARPT 15 MI AWAY ON A HDG TO 270, WHICH WAS BLAIRSVILLE, GA ARPT. ANOTHER ACFT WAS TRANSMITTING TO ME THE PHONE # TO CALL AFTER LNDG. CENTER HAD TOLD THIS OTHER ACFT THAT HE (CENTER) WAS WORKING AN EMER. (I HAD NOT REQUESTED NOR CONFIRMED THAT I WAS AN EMER.) I NOTIFIED CENTER THAT I HAD BLAIRSVILLE IN SIGHT AND HAD BEGUN MY DSCNT. AFTER LNDG I CALLED ATLANTA CENTER AND TOLD HIM THAT WE WERE ON THE GND. AFTER SEVERAL MORE QUESTIONS HE TOLD ME NOTHING FURTHER WAS NEEDED. AFTER LOSING THE LEFT ALTERNATOR I FELT THAT BEING GOOD VFR AND CONTINUING THE FLT WAS SAFE. ALTERNATOR OUTPUT ON THE RIGHT SIDE WAS GOOD, 20 AMPS. AT 1 HR 45 MIN I TURNED ON THE FUEL BOOST PUMPS TO CHANGE TANKS. IT WAS AT THIS TIME THE RIGHT ALTERNATOR AMPS WENT TO 0 AND NO WARNING LIGHT CAME ON. IT WAS AT THIS TIME THAT THE BEST THING WAS TO LAND AS SOON AS POSSIBLE WHILE THERE WAS STILL DAYLIGHT. THE CAUSE OF THE FAILURE WAS LEFT VOLTAGE REGULATOR AND ALTERNATOR WERE BOTH BAD AND HAD FAILED. THERE HAS BEEN NO DETERMINATION AS TO WHY MY RIGHT SIDE WENT OFF LINE BUT YET SHOWED NO EMER LIGHT.

Data retrieved from NASA's ASRS site as of August 2007 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.