Narrative:

The right alternator dropped off line 3 times within a short time span. After troubleshooting, the right alternator was determined to be at fault and would not reset the last time. Within mins the left alternator dropped off line and would not reset. Annunciators on the glare shield alerted the pilot when the alternators went off line. At this time ZME was alerted of the problem and asked to leave the frequency for a short time. Then load shedding was started on the aircraft. When returning to ZME, pilot asked for vector to little rock adams and advised them of that possibility and ASR and no gyroscope would be needed and permission to turn radio off and call back in 10 mins and was approved. When returning to ZME pilot was advised lit was below ASR minimums. At this time pilot asked to get WX for suitable airport, memphis advised of fsm and vectors was given. Within mins memphis advised fsm would not be suitable. Pilot asked for WX for a VFR landing as battery power was questionable. Memphis advised that fayetteville drake field was reporting VFR conditions and a heading was given and frequency change to razorback approach. Razorback approach give heading and distance information and a clearance to descend to 3000 ft. At 3200 ft aircraft descended below clouds with about 3 mi visibility. Ceiling was about 1700 ft above ground level. A safe landing was made without incident. Just before aircraft was handed off to razorback approach pilot had requested lower altitude (to remain clear of clouds, this was not told to center) and I don't think clearance was ever given from 8000 ft. Pilot went ahead declared an emergency and advised center that descent was being initiated. Quite a few events happened in a very short time so a sketchy at best report has been given. ATC did an excellent job with the situation. Time limits on critical parts such as alternators and gyro pumps would be helpful on small aircraft. Some type of load shedding for aircraft with this much IFR capability that would leave only minimum equipment. A handheld radio was available to pilot but unfamiliarity with it and cockpit workload precluded its use. Requirements for handheld radios and GPS units in the future would be a godsend. I will carry and be familiar with my own in the future. Callback conversation with reporter revealed the following information: when reporter pilot wrote his report, it was still unknown what caused the dual alternator failure. Subsequent investigation revealed that the right alternator had an internal failure and locked up. At first, it was thought that the additional electrical load caused the second alternator to drop off. However, testing the aircraft with just 1 alternator, it was proven that 1 alternator could carry a full load, including all anti-icing. And, the left alternator did reset and was usable just prior to the emergency landing. The only known factor that could have caused the left alternator to drop off could have been attributed to icing. The aircraft was in light icing conditions and, if the chin scoop inlet for alternator cooling had become plugged with ice, thus reducing the cooling airflow, that could explain it. Also, after the aircraft was descended to a lower altitude and out of the clouds, the alternator was reset. Since the pilot declared an emergency, the local FSDO maintenance looked into the event with no action. Reporter wished that he had been more familiar with the cellular telephone which was in the aircraft, but under the circumstances of minimal instruments and using a flashlight to see them, he would have needed more hands to also use a telephone. Reporter praises the controllers for their help in directing him to a suitable airport for landing.

Related reports:

Google
 

Original NASA ASRS Text

Title: DUAL ALTERNATOR FAILURE WITH POOR WX CONDITIONS, ACFT DIVERTED AND VECTORED BY ATC TO SUITABLE ARPT WHERE AN EMER WAS DECLARED, 1 ALTERNATOR WAS RESET, AND THE ACFT LANDED UNEVENTFULLY.

Narrative: THE R ALTERNATOR DROPPED OFF LINE 3 TIMES WITHIN A SHORT TIME SPAN. AFTER TROUBLESHOOTING, THE R ALTERNATOR WAS DETERMINED TO BE AT FAULT AND WOULD NOT RESET THE LAST TIME. WITHIN MINS THE L ALTERNATOR DROPPED OFF LINE AND WOULD NOT RESET. ANNUNCIATORS ON THE GLARE SHIELD ALERTED THE PLT WHEN THE ALTERNATORS WENT OFF LINE. AT THIS TIME ZME WAS ALERTED OF THE PROB AND ASKED TO LEAVE THE FREQ FOR A SHORT TIME. THEN LOAD SHEDDING WAS STARTED ON THE ACFT. WHEN RETURNING TO ZME, PLT ASKED FOR VECTOR TO LITTLE ROCK ADAMS AND ADVISED THEM OF THAT POSSIBILITY AND ASR AND NO GYROSCOPE WOULD BE NEEDED AND PERMISSION TO TURN RADIO OFF AND CALL BACK IN 10 MINS AND WAS APPROVED. WHEN RETURNING TO ZME PLT WAS ADVISED LIT WAS BELOW ASR MINIMUMS. AT THIS TIME PLT ASKED TO GET WX FOR SUITABLE ARPT, MEMPHIS ADVISED OF FSM AND VECTORS WAS GIVEN. WITHIN MINS MEMPHIS ADVISED FSM WOULD NOT BE SUITABLE. PLT ASKED FOR WX FOR A VFR LNDG AS BATTERY PWR WAS QUESTIONABLE. MEMPHIS ADVISED THAT FAYETTEVILLE DRAKE FIELD WAS RPTING VFR CONDITIONS AND A HEADING WAS GIVEN AND FREQ CHANGE TO RAZORBACK APCH. RAZORBACK APCH GIVE HDG AND DISTANCE INFO AND A CLRNC TO DSND TO 3000 FT. AT 3200 FT ACFT DSNDED BELOW CLOUDS WITH ABOUT 3 MI VISIBILITY. CEILING WAS ABOUT 1700 FT ABOVE GND LEVEL. A SAFE LNDG WAS MADE WITHOUT INCIDENT. JUST BEFORE ACFT WAS HANDED OFF TO RAZORBACK APCH PLT HAD REQUESTED LOWER ALT (TO REMAIN CLR OF CLOUDS, THIS WAS NOT TOLD TO CTR) AND I DON'T THINK CLRNC WAS EVER GIVEN FROM 8000 FT. PLT WENT AHEAD DECLARED AN EMER AND ADVISED CTR THAT DSCNT WAS BEING INITIATED. QUITE A FEW EVENTS HAPPENED IN A VERY SHORT TIME SO A SKETCHY AT BEST RPT HAS BEEN GIVEN. ATC DID AN EXCELLENT JOB WITH THE SIT. TIME LIMITS ON CRITICAL PARTS SUCH AS ALTERNATORS AND GYRO PUMPS WOULD BE HELPFUL ON SMALL ACFT. SOME TYPE OF LOAD SHEDDING FOR ACFT WITH THIS MUCH IFR CAPABILITY THAT WOULD LEAVE ONLY MINIMUM EQUIP. A HANDHELD RADIO WAS AVAILABLE TO PLT BUT UNFAMILIARITY WITH IT AND COCKPIT WORKLOAD PRECLUDED ITS USE. REQUIREMENTS FOR HANDHELD RADIOS AND GPS UNITS IN THE FUTURE WOULD BE A GODSEND. I WILL CARRY AND BE FAMILIAR WITH MY OWN IN THE FUTURE. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: WHEN RPTR PLT WROTE HIS RPT, IT WAS STILL UNKNOWN WHAT CAUSED THE DUAL ALTERNATOR FAILURE. SUBSEQUENT INVESTIGATION REVEALED THAT THE R ALTERNATOR HAD AN INTERNAL FAILURE AND LOCKED UP. AT FIRST, IT WAS THOUGHT THAT THE ADDITIONAL ELECTRICAL LOAD CAUSED THE SECOND ALTERNATOR TO DROP OFF. HOWEVER, TESTING THE ACFT WITH JUST 1 ALTERNATOR, IT WAS PROVEN THAT 1 ALTERNATOR COULD CARRY A FULL LOAD, INCLUDING ALL ANTI-ICING. AND, THE L ALTERNATOR DID RESET AND WAS USABLE JUST PRIOR TO THE EMER LNDG. THE ONLY KNOWN FACTOR THAT COULD HAVE CAUSED THE L ALTERNATOR TO DROP OFF COULD HAVE BEEN ATTRIBUTED TO ICING. THE ACFT WAS IN LIGHT ICING CONDITIONS AND, IF THE CHIN SCOOP INLET FOR ALTERNATOR COOLING HAD BECOME PLUGGED WITH ICE, THUS REDUCING THE COOLING AIRFLOW, THAT COULD EXPLAIN IT. ALSO, AFTER THE ACFT WAS DSNDED TO A LOWER ALT AND OUT OF THE CLOUDS, THE ALTERNATOR WAS RESET. SINCE THE PLT DECLARED AN EMER, THE LCL FSDO MAINT LOOKED INTO THE EVENT WITH NO ACTION. RPTR WISHED THAT HE HAD BEEN MORE FAMILIAR WITH THE CELLULAR TELEPHONE WHICH WAS IN THE ACFT, BUT UNDER THE CIRCUMSTANCES OF MINIMAL INSTS AND USING A FLASHLIGHT TO SEE THEM, HE WOULD HAVE NEEDED MORE HANDS TO ALSO USE A TELEPHONE. RPTR PRAISES THE CTLRS FOR THEIR HELP IN DIRECTING HIM TO A SUITABLE ARPT FOR LNDG.

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.