Narrative:

During handoff from madison departure to rockford departure, ATC asked us to recycle the transponder. We did. They said it was dropping out. This was the first sign we were having power problems. After passing the rfd VOR, the radios got 'mushy' sounding and the VOR to/from flog changed with the transmitter. Suspected we were experiencing a power failure. There had been no indication on the ammeter that there was any discharge. Also, the 'low voltage' light never came on! We were just moving from VFR WX over a cloud deck (we were VFR on top) when it became obvious the radios were out, as was the transponder and all our navigation gear. Just prior to this I informed ATC that I suspected voltage failure and would return to rockford. He told me to follow my flight plan. I wilco'ed. When the radios failed I was VFR on top and had just passed rockford a few moments before. I did a 180 degree turn and followed the compass back to the vicinity of rfd. Upon sighting the field, we flew upwind along side of runway 36 (I knew the wind was from the north) expecting to do a midfield crosswind and left traffic to runway 36. As we were along side the approach end of runway 36, the tower gave us a green light. I made a long slow final to assure the gear had been pumped down and locked, I thought the green light for gear lock was glowing dimly. We had no electricity. Landed gently with no flaps. Followed the crash truck to parking area, filled out reports, called tower. Was asked if this was emergency? Said no. Rules specified what to do and it works. The local FBO did repair. Confirmed dead battery and rebuilt alternator. I will learn to watch for other signs of failure, even if instruments don't indicate them. Ammeter and low voltage light were worthless! Passenger was on first small plane ride and panicked some at first. Calmed down when I explained what we would do.

Google
 

Original NASA ASRS Text

Title: GA PLT ON IFR PLEASURE FLT EXPERIENCES ELECTRICAL FAILURE.

Narrative: DURING HDOF FROM MADISON DEP TO ROCKFORD DEP, ATC ASKED US TO RECYCLE THE XPONDER. WE DID. THEY SAID IT WAS DROPPING OUT. THIS WAS THE FIRST SIGN WE WERE HAVING PWR PROBS. AFTER PASSING THE RFD VOR, THE RADIOS GOT 'MUSHY' SOUNDING AND THE VOR TO/FROM FLOG CHANGED WITH THE XMITTER. SUSPECTED WE WERE EXPERIENCING A PWR FAILURE. THERE HAD BEEN NO INDICATION ON THE AMMETER THAT THERE WAS ANY DISCHARGE. ALSO, THE 'LOW VOLTAGE' LIGHT NEVER CAME ON! WE WERE JUST MOVING FROM VFR WX OVER A CLOUD DECK (WE WERE VFR ON TOP) WHEN IT BECAME OBVIOUS THE RADIOS WERE OUT, AS WAS THE XPONDER AND ALL OUR NAV GEAR. JUST PRIOR TO THIS I INFORMED ATC THAT I SUSPECTED VOLTAGE FAILURE AND WOULD RETURN TO ROCKFORD. HE TOLD ME TO FOLLOW MY FLT PLAN. I WILCO'ED. WHEN THE RADIOS FAILED I WAS VFR ON TOP AND HAD JUST PASSED ROCKFORD A FEW MOMENTS BEFORE. I DID A 180 DEG TURN AND FOLLOWED THE COMPASS BACK TO THE VICINITY OF RFD. UPON SIGHTING THE FIELD, WE FLEW UPWIND ALONG SIDE OF RWY 36 (I KNEW THE WIND WAS FROM THE N) EXPECTING TO DO A MIDFIELD XWIND AND L TFC TO RWY 36. AS WE WERE ALONG SIDE THE APCH END OF RWY 36, THE TWR GAVE US A GREEN LIGHT. I MADE A LONG SLOW FINAL TO ASSURE THE GEAR HAD BEEN PUMPED DOWN AND LOCKED, I THOUGHT THE GREEN LIGHT FOR GEAR LOCK WAS GLOWING DIMLY. WE HAD NO ELECTRICITY. LANDED GENTLY WITH NO FLAPS. FOLLOWED THE CRASH TRUCK TO PARKING AREA, FILLED OUT RPTS, CALLED TWR. WAS ASKED IF THIS WAS EMER? SAID NO. RULES SPECIFIED WHAT TO DO AND IT WORKS. THE LCL FBO DID REPAIR. CONFIRMED DEAD BATTERY AND REBUILT ALTERNATOR. I WILL LEARN TO WATCH FOR OTHER SIGNS OF FAILURE, EVEN IF INSTRUMENTS DON'T INDICATE THEM. AMMETER AND LOW VOLTAGE LIGHT WERE WORTHLESS! PAX WAS ON FIRST SMALL PLANE RIDE AND PANICKED SOME AT FIRST. CALMED DOWN WHEN I EXPLAINED WHAT WE WOULD DO.

Data retrieved from NASA's ASRS site as of July 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.