Narrative:

Flight departed pfn on IFR flight plan to mgm. Aircraft cleared on course and to 6000 ft (final). Intermittent IMC during uneventful climb. Leveled at 6000 ft, completed post-climb/cruise checklist, still on pam departure frequency. Master caution illuminated, caution panel indicated low voltage alarm, ammeter at -10A, then alarm off and ammeter normal. Approximately 3 mins later, symptoms reappeared and remained. Aircraft in VMC conditions. Contacted pam, advised I needed to return to airport immediately. Decided to declare emergency. Pam responded with clearance: present position, pfn direct. I turned heading bug to new heading (aircraft autoplt engaged at reaching 6000 ft) and began emergency checklist. At some point, I inadvertently disengaged altitude hold and allowed aircraft to descend to 5000 ft. (Didn't notice it until pam approach inquired regarding altitude, then cleared me to maintain 5000 ft and 'don't do this to me.' I apologized (for being stupid). Pam approach then cleared me to 3000 ft and the VOR-a approach to pfn, which was uneventful. Basically, the reason for this report is that I failed to do what I drill into my students -- fly the airplane, first, last and always. I was engrossed in the checklist and didn't notice altitude hold was no longer engaged until pam questioned me. Mitigating factor is relative unfamiliarity with this airplane as opposed to the 67F I'd owned and flown for 20 yrs (it has mechanical gear/flaps). This airplane is basically an electric airplane, and I devoted undue attention to a (relatively) minor problem to the exclusion of commanding the flight. In retrospect, I should have declared an emergency, just to get the additional help. Electrical problem was broken alternator field ground, caused by inadequate repair at some earlier date.

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Original NASA ASRS Text

Title: ALTDEV DURING A RETURN AND LAND MANDATED BY AN ELECTRICAL PWR LOSS IN AN SMA, 27 MI NW OF PFN.

Narrative: FLT DEPARTED PFN ON IFR FLT PLAN TO MGM. ACFT CLRED ON COURSE AND TO 6000 FT (FINAL). INTERMITTENT IMC DURING UNEVENTFUL CLB. LEVELED AT 6000 FT, COMPLETED POST-CLB/CRUISE CHKLIST, STILL ON PAM DEP FREQ. MASTER CAUTION ILLUMINATED, CAUTION PANEL INDICATED LOW VOLTAGE ALARM, AMMETER AT -10A, THEN ALARM OFF AND AMMETER NORMAL. APPROX 3 MINS LATER, SYMPTOMS REAPPEARED AND REMAINED. ACFT IN VMC CONDITIONS. CONTACTED PAM, ADVISED I NEEDED TO RETURN TO ARPT IMMEDIATELY. DECIDED TO DECLARE EMER. PAM RESPONDED WITH CLRNC: PRESENT POS, PFN DIRECT. I TURNED HDG BUG TO NEW HDG (ACFT AUTOPLT ENGAGED AT REACHING 6000 FT) AND BEGAN EMER CHKLIST. AT SOME POINT, I INADVERTENTLY DISENGAGED ALT HOLD AND ALLOWED ACFT TO DSND TO 5000 FT. (DIDN'T NOTICE IT UNTIL PAM APCH INQUIRED REGARDING ALT, THEN CLRED ME TO MAINTAIN 5000 FT AND 'DON'T DO THIS TO ME.' I APOLOGIZED (FOR BEING STUPID). PAM APCH THEN CLRED ME TO 3000 FT AND THE VOR-A APCH TO PFN, WHICH WAS UNEVENTFUL. BASICALLY, THE REASON FOR THIS RPT IS THAT I FAILED TO DO WHAT I DRILL INTO MY STUDENTS -- FLY THE AIRPLANE, FIRST, LAST AND ALWAYS. I WAS ENGROSSED IN THE CHKLIST AND DIDN'T NOTICE ALT HOLD WAS NO LONGER ENGAGED UNTIL PAM QUESTIONED ME. MITIGATING FACTOR IS RELATIVE UNFAMILIARITY WITH THIS AIRPLANE AS OPPOSED TO THE 67F I'D OWNED AND FLOWN FOR 20 YRS (IT HAS MECHANICAL GEAR/FLAPS). THIS AIRPLANE IS BASICALLY AN ELECTRIC AIRPLANE, AND I DEVOTED UNDUE ATTN TO A (RELATIVELY) MINOR PROB TO THE EXCLUSION OF COMMANDING THE FLT. IN RETROSPECT, I SHOULD HAVE DECLARED AN EMER, JUST TO GET THE ADDITIONAL HELP. ELECTRICAL PROB WAS BROKEN ALTERNATOR FIELD GND, CAUSED BY INADEQUATE REPAIR AT SOME EARLIER DATE.

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.