Narrative:

I was flying a C310Q from 3KM to hys. The evening briefing indicated the conditions at rsl were 1300 ft scattered, 1500 ft broken with 5 mi visibility-fog and winds 340 degrees at 6 KTS. Gbd and hys conditions were similar. A flight plan was filed for 3KM direct hys at 8000 ft, 45 mins en route. The airplane was retrieved from the hangar and was preflted. No abnormalities were idented (specifically both the left and right alternator belts were present and normal). The aircraft was started and the preflight checklist was completed. All system were functioning normally. An IFR clearance was obtained and the airplane departed 3KM. The departure and initial climb phases were uneventful and I was cleared on course (300 degrees) and up to 8000 ft MSL. The first 20 mins of the flight were normal. While climbing through 6000 ft MSL the right alternator failure light came on. The left alternator was operating normally as indicated by both the voltmeter and non lighted left alternator failure light. As the aircraft was IMC, initial action of decreasing the electrical load was accomplished. The pitot heat and cabin heater were maintained in the 'on' position as the outside air temperature indicated 35 degrees. After leveling and trimming the airplane at 8000 ft MSL, the procedure list was consulted. The right alternator did not regain function and the right failure light continued to be lighted. During the procedure it was noted that the right alternator circuit breaker was open. The right alternator was selected 'off,' 2 mins were allowed for cooling and the circuit breaker was reset and the right alternator was selected to the 'on' position. The panel lights transiently dimmed and the right alternator failure light did not go out. The left alternator appeared to remain functional as the left failure light came on during, but went out after, the attempt to reset the right alternator. Approximately 10-15 mins after this string of events started it became apparent that the electrical system was not operating as expected. Although the left alternator failure light was not on, it was suspected that the system was not charging the battery. The push to test showed that the left alternator failure light was not burned out. The circuit breakers were re- inspected and it was found that both the right and left alternator circuit breakers were now open. An emergency was declared to ZKC. Radio contact was poor at best. An initial turn towards sln was started from the hys 120 degree radial at about 50 NM. Both alternators were selected 'off,' allowed to cool. It was found that neither circuit breakers would reset. As there were several airports in the near and adjacent areas the landing gear were extended. As it was obvious that the communication/navigation radios were failed I decided to re-evaluate the situation, options and plan an action. The wichita VFR sectional map was also opened and confirmed that while great bend gbd and hutchinson hut airports were near, there were too many tall radio towers near them to attempt to go there. Lyons lyo was very close but had 6 radio towers near the airport. To continue towards sln was not a good choice as both restr areas R3601A and B were between the current position and sln. 9k7 was the best option. It was almost due north of the current position and only 23 mi away. I had been into the airport many times and was familiar with the local terrain. The runway is almost 4000 ft long and the south end lines up with a correctional facility that has numerous very high intensity lights that are bright orange and visible from many mi away. As I crossed over what I believed to be lyons lyo the diffuse glow of light could be seen through the clouds. A garmin GPS 95 xl was turned on and confirmed the current position and ground speed and heading and distance to 9k7. The GPS had been loaned to another pilot the day before and had very low batteries and was expected to work for only a short period of time at best. A stabilized descent of 400-500 FPM was established that allowed the airplane to be at 2500 ft MSL when at a distance of about 3 mi sse of 9k7. The sectional chart indicated the maximum elevation figure to be 2300 ft MSL near 9k7. The city of ellsworth and the prison lights were visible as the airplane crossed the navigation point and a visual approach and landing were made in VFR conditions from that navigation point. The mechanic has started inspecting the system and so far has found that the right alternator belt broke. The left alternator circuit breaker opens at about 1/10 the intended current flow and will not reset until the right side is operating normal. Also the left circuit breaker does not completely do its job and allows some voltage to pass which is sufficient to keep the failure light from coming on.

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Original NASA ASRS Text

Title: PLT OF C310 EXPERIENCES R ALTERNATOR FAILURE THEN L RESULTING IN COMPLETE ELECTRICAL FAILURE IN IMC. GPS ABOARD AND VFR CHARTS USED TO FIND SUITABLE EMER ARPT.

Narrative: I WAS FLYING A C310Q FROM 3KM TO HYS. THE EVENING BRIEFING INDICATED THE CONDITIONS AT RSL WERE 1300 FT SCATTERED, 1500 FT BROKEN WITH 5 MI VISIBILITY-FOG AND WINDS 340 DEGS AT 6 KTS. GBD AND HYS CONDITIONS WERE SIMILAR. A FLT PLAN WAS FILED FOR 3KM DIRECT HYS AT 8000 FT, 45 MINS ENRTE. THE AIRPLANE WAS RETRIEVED FROM THE HANGAR AND WAS PREFLTED. NO ABNORMALITIES WERE IDENTED (SPECIFICALLY BOTH THE L AND R ALTERNATOR BELTS WERE PRESENT AND NORMAL). THE ACFT WAS STARTED AND THE PREFLT CHKLIST WAS COMPLETED. ALL SYS WERE FUNCTIONING NORMALLY. AN IFR CLRNC WAS OBTAINED AND THE AIRPLANE DEPARTED 3KM. THE DEP AND INITIAL CLB PHASES WERE UNEVENTFUL AND I WAS CLRED ON COURSE (300 DEGS) AND UP TO 8000 FT MSL. THE FIRST 20 MINS OF THE FLT WERE NORMAL. WHILE CLBING THROUGH 6000 FT MSL THE R ALTERNATOR FAILURE LIGHT CAME ON. THE L ALTERNATOR WAS OPERATING NORMALLY AS INDICATED BY BOTH THE VOLTMETER AND NON LIGHTED L ALTERNATOR FAILURE LIGHT. AS THE ACFT WAS IMC, INITIAL ACTION OF DECREASING THE ELECTRICAL LOAD WAS ACCOMPLISHED. THE PITOT HEAT AND CABIN HEATER WERE MAINTAINED IN THE 'ON' POS AS THE OUTSIDE AIR TEMP INDICATED 35 DEGS. AFTER LEVELING AND TRIMMING THE AIRPLANE AT 8000 FT MSL, THE PROC LIST WAS CONSULTED. THE R ALTERNATOR DID NOT REGAIN FUNCTION AND THE R FAILURE LIGHT CONTINUED TO BE LIGHTED. DURING THE PROC IT WAS NOTED THAT THE R ALTERNATOR CIRCUIT BREAKER WAS OPEN. THE R ALTERNATOR WAS SELECTED 'OFF,' 2 MINS WERE ALLOWED FOR COOLING AND THE CIRCUIT BREAKER WAS RESET AND THE R ALTERNATOR WAS SELECTED TO THE 'ON' POS. THE PANEL LIGHTS TRANSIENTLY DIMMED AND THE R ALTERNATOR FAILURE LIGHT DID NOT GO OUT. THE L ALTERNATOR APPEARED TO REMAIN FUNCTIONAL AS THE L FAILURE LIGHT CAME ON DURING, BUT WENT OUT AFTER, THE ATTEMPT TO RESET THE R ALTERNATOR. APPROX 10-15 MINS AFTER THIS STRING OF EVENTS STARTED IT BECAME APPARENT THAT THE ELECTRICAL SYS WAS NOT OPERATING AS EXPECTED. ALTHOUGH THE L ALTERNATOR FAILURE LIGHT WAS NOT ON, IT WAS SUSPECTED THAT THE SYS WAS NOT CHARGING THE BATTERY. THE PUSH TO TEST SHOWED THAT THE L ALTERNATOR FAILURE LIGHT WAS NOT BURNED OUT. THE CIRCUIT BREAKERS WERE RE- INSPECTED AND IT WAS FOUND THAT BOTH THE R AND L ALTERNATOR CIRCUIT BREAKERS WERE NOW OPEN. AN EMER WAS DECLARED TO ZKC. RADIO CONTACT WAS POOR AT BEST. AN INITIAL TURN TOWARDS SLN WAS STARTED FROM THE HYS 120 DEG RADIAL AT ABOUT 50 NM. BOTH ALTERNATORS WERE SELECTED 'OFF,' ALLOWED TO COOL. IT WAS FOUND THAT NEITHER CIRCUIT BREAKERS WOULD RESET. AS THERE WERE SEVERAL ARPTS IN THE NEAR AND ADJACENT AREAS THE LNDG GEAR WERE EXTENDED. AS IT WAS OBVIOUS THAT THE COM/NAV RADIOS WERE FAILED I DECIDED TO RE-EVALUATE THE SIT, OPTIONS AND PLAN AN ACTION. THE WICHITA VFR SECTIONAL MAP WAS ALSO OPENED AND CONFIRMED THAT WHILE GREAT BEND GBD AND HUTCHINSON HUT ARPTS WERE NEAR, THERE WERE TOO MANY TALL RADIO TWRS NEAR THEM TO ATTEMPT TO GO THERE. LYONS LYO WAS VERY CLOSE BUT HAD 6 RADIO TWRS NEAR THE ARPT. TO CONTINUE TOWARDS SLN WAS NOT A GOOD CHOICE AS BOTH RESTR AREAS R3601A AND B WERE BTWN THE CURRENT POS AND SLN. 9K7 WAS THE BEST OPTION. IT WAS ALMOST DUE N OF THE CURRENT POS AND ONLY 23 MI AWAY. I HAD BEEN INTO THE ARPT MANY TIMES AND WAS FAMILIAR WITH THE LCL TERRAIN. THE RWY IS ALMOST 4000 FT LONG AND THE S END LINES UP WITH A CORRECTIONAL FACILITY THAT HAS NUMEROUS VERY HIGH INTENSITY LIGHTS THAT ARE BRIGHT ORANGE AND VISIBLE FROM MANY MI AWAY. AS I CROSSED OVER WHAT I BELIEVED TO BE LYONS LYO THE DIFFUSE GLOW OF LIGHT COULD BE SEEN THROUGH THE CLOUDS. A GARMIN GPS 95 XL WAS TURNED ON AND CONFIRMED THE CURRENT POS AND GND SPD AND HEADING AND DISTANCE TO 9K7. THE GPS HAD BEEN LOANED TO ANOTHER PLT THE DAY BEFORE AND HAD VERY LOW BATTERIES AND WAS EXPECTED TO WORK FOR ONLY A SHORT PERIOD OF TIME AT BEST. A STABILIZED DSCNT OF 400-500 FPM WAS ESTABLISHED THAT ALLOWED THE AIRPLANE TO BE AT 2500 FT MSL WHEN AT A DISTANCE OF ABOUT 3 MI SSE OF 9K7. THE SECTIONAL CHART INDICATED THE MAX ELEVATION FIGURE TO BE 2300 FT MSL NEAR 9K7. THE CITY OF ELLSWORTH AND THE PRISON LIGHTS WERE VISIBLE AS THE AIRPLANE CROSSED THE NAV POINT AND A VISUAL APCH AND LNDG WERE MADE IN VFR CONDITIONS FROM THAT NAV POINT. THE MECH HAS STARTED INSPECTING THE SYS AND SO FAR HAS FOUND THAT THE R ALTERNATOR BELT BROKE. THE L ALTERNATOR CIRCUIT BREAKER OPENS AT ABOUT 1/10 THE INTENDED CURRENT FLOW AND WILL NOT RESET UNTIL THE R SIDE IS OPERATING NORMAL. ALSO THE L CIRCUIT BREAKER DOES NOT COMPLETELY DO ITS JOB AND ALLOWS SOME VOLTAGE TO PASS WHICH IS SUFFICIENT TO KEEP THE FAILURE LIGHT FROM COMING ON.

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.