Narrative:

Approximately 40 mi outside huntsville, al, center stated they had lost my transponder. Turned me over to huntsville approach, who cleared me down to 4000. They also were not picking up my transponder. I then noticed my alternator needle indicated a discharge condition. I tried to reset the alternator by turning the master switch off and on with no results. I then notified huntsville approach and would like an expedited approach due to loss of alternator. They cleared me for the VOR approach and vectored me toward the approach. I shut down the transponder, 1 radio, and DME to save power and then discovered the alternator must have shorted as it now indicated a major discharge and the remaining radio went dead. I was at 3000 ft at this time. In trying to deal with aircraft system, I had lost track of where I was and had let heading get off. I saw some light spots below so I dropped down to 1500 which was below assigned altitude of huntsville approach. After descending, I turned off the alternator and regained use of my #1 radio off battery only. I called huntsville approach asked where I was. They directed me toward the huntsville airport but at that point I saw the decatur airport below me so I cancelled IFR and landed at decatur. Battery was down to the point I had no flaps and had to manually pump down the gear. Future thoughts -- I had a portable radio which had a dead battery (part of my distraction). Next time -- monitor headings and altitudes while timing the approach. My DME was working until alternator discharge. It would have given me a better idea of how long to hold altitude before descending. Make sure equipment is charged and take an alkaline battery pack. Monitor system better. I had approach plates in a holder which obscured the alternator gauge.

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Original NASA ASRS Text

Title: SMA PLT HAS ALTERNATOR FAILURE ON IFR FLT PLAN IN IMC WX. DISORIENTED, HE DSNDS BELOW ASSIGNED. BECOMES VISUAL, CANCELS IFR, LANDS.

Narrative: APPROX 40 MI OUTSIDE HUNTSVILLE, AL, CTR STATED THEY HAD LOST MY TRANSPONDER. TURNED ME OVER TO HUNTSVILLE APCH, WHO CLRED ME DOWN TO 4000. THEY ALSO WERE NOT PICKING UP MY TRANSPONDER. I THEN NOTICED MY ALTERNATOR NEEDLE INDICATED A DISCHARGE CONDITION. I TRIED TO RESET THE ALTERNATOR BY TURNING THE MASTER SWITCH OFF AND ON WITH NO RESULTS. I THEN NOTIFIED HUNTSVILLE APCH AND WOULD LIKE AN EXPEDITED APCH DUE TO LOSS OF ALTERNATOR. THEY CLRED ME FOR THE VOR APCH AND VECTORED ME TOWARD THE APCH. I SHUT DOWN THE TRANSPONDER, 1 RADIO, AND DME TO SAVE PWR AND THEN DISCOVERED THE ALTERNATOR MUST HAVE SHORTED AS IT NOW INDICATED A MAJOR DISCHARGE AND THE REMAINING RADIO WENT DEAD. I WAS AT 3000 FT AT THIS TIME. IN TRYING TO DEAL WITH ACFT SYS, I HAD LOST TRACK OF WHERE I WAS AND HAD LET HDG GET OFF. I SAW SOME LIGHT SPOTS BELOW SO I DROPPED DOWN TO 1500 WHICH WAS BELOW ASSIGNED ALT OF HUNTSVILLE APCH. AFTER DSNDING, I TURNED OFF THE ALTERNATOR AND REGAINED USE OF MY #1 RADIO OFF BATTERY ONLY. I CALLED HUNTSVILLE APCH ASKED WHERE I WAS. THEY DIRECTED ME TOWARD THE HUNTSVILLE ARPT BUT AT THAT POINT I SAW THE DECATUR ARPT BELOW ME SO I CANCELLED IFR AND LANDED AT DECATUR. BATTERY WAS DOWN TO THE POINT I HAD NO FLAPS AND HAD TO MANUALLY PUMP DOWN THE GEAR. FUTURE THOUGHTS -- I HAD A PORTABLE RADIO WHICH HAD A DEAD BATTERY (PART OF MY DISTR). NEXT TIME -- MONITOR HDGS AND ALTS WHILE TIMING THE APCH. MY DME WAS WORKING UNTIL ALTERNATOR DISCHARGE. IT WOULD HAVE GIVEN ME A BETTER IDEA OF HOW LONG TO HOLD ALT BEFORE DSNDING. MAKE SURE EQUIP IS CHARGED AND TAKE AN ALKALINE BATTERY PACK. MONITOR SYS BETTER. I HAD APCH PLATES IN A HOLDER WHICH OBSCURED THE ALTERNATOR GAUGE.

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.