Narrative:

Flying along at 2500 ft inbound to ZZZ1. For touch and go noticed low volt light came on. Abandoned approach. Changed course to ZZZ (aircraft's home base). At about 10-12 NM northeast of ZZZ radios failed completely; after getting clearance from tower saying 'proceed direct runway 19.' kept on current course and when entering traffic pattern at ZZZ turned avionics on and the radio worked just long enough to hear tower say 'cleared to land runway 21.' after verifying our clearance; I landed the aircraft with no incidence. After taxiing clear of runway 21; all electrical equipment was dead; so I called tower from cell phone to get taxi clearance to the ramp. They approved. I taxied; shut aircraft down and secured it. Callback conversation with reporter revealed the following information: on the approach the low voltage light illuminated and when transmitting; the lighting dimmed. On returning to the departure airport the radios failed completely. Maintenance found alternator was not reset after emergency power check on preflight cockpit check. No emergency was declared due to paperwork concern. The reporter stated he has now completed 2 hours of flight school on C172 electrical system and preflight checks.

Google
 

Original NASA ASRS Text

Title: A C172 ON APCH AT 2500 FT RETURNED TO DEP ARPT DUE TO LOW VOLTAGE WARNING LIGHT ILLUMINATED. 10 NM FROM ARPT RADIOS FAILED COMPLETELY.

Narrative: FLYING ALONG AT 2500 FT INBOUND TO ZZZ1. FOR TOUCH AND GO NOTICED LOW VOLT LIGHT CAME ON. ABANDONED APCH. CHANGED COURSE TO ZZZ (ACFT'S HOME BASE). AT ABOUT 10-12 NM NE OF ZZZ RADIOS FAILED COMPLETELY; AFTER GETTING CLRNC FROM TWR SAYING 'PROCEED DIRECT RWY 19.' KEPT ON CURRENT COURSE AND WHEN ENTERING TFC PATTERN AT ZZZ TURNED AVIONICS ON AND THE RADIO WORKED JUST LONG ENOUGH TO HEAR TWR SAY 'CLRED TO LAND RWY 21.' AFTER VERIFYING OUR CLRNC; I LANDED THE ACFT WITH NO INCIDENCE. AFTER TAXIING CLR OF RWY 21; ALL ELECTRICAL EQUIP WAS DEAD; SO I CALLED TWR FROM CELL PHONE TO GET TAXI CLRNC TO THE RAMP. THEY APPROVED. I TAXIED; SHUT ACFT DOWN AND SECURED IT. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: ON THE APCH THE LOW VOLTAGE LIGHT ILLUMINATED AND WHEN XMITTING; THE LIGHTING DIMMED. ON RETURNING TO THE DEP ARPT THE RADIOS FAILED COMPLETELY. MAINT FOUND ALTERNATOR WAS NOT RESET AFTER EMER PWR CHK ON PREFLT COCKPIT CHK. NO EMER WAS DECLARED DUE TO PAPERWORK CONCERN. THE RPTR STATED HE HAS NOW COMPLETED 2 HRS OF FLT SCHOOL ON C172 ELECTRICAL SYS AND PREFLT CHKS.

Data retrieved from NASA's ASRS site as of January 2009 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.