Narrative:

After leveloff at FL350 we started to get several unrelated system failures. Circuit breakers started popping and after 2-3 mins the left side of the aircraft lost most of its electrical power. Lost the captain's VOR and radio and soon thereafter, the attitude indicator. The electrical abnormalities checklist was ran but no system failures were indicated. We deduced we had a problem with the left AC bus but had no 'bus' failure lights and the bus did not automatic switch to the right side as it should have. It was VFR and we returned to dtw uneventfully. It may have been a different case had it been IFR. The DC9 is getting old and electrical failures are more common. What is disturbing is the warning and automatic switching system are not working as they should. Callback conversation with reporter revealed the following information: reporter stated that the flight instruments on the captain's side began to fail without indications of any electrical power loss, such as the xfer bus illuminating or any other red lights. When the decision was made to return to point of departure, an emergency was declared. Only instruments on the right side kept working. There was only 1 circuit breaker that had tripped, which was a circuit breaker for a single phase of a 3 phase generator. After the aircraft landed and taxied to the gate and parked, as the engines were being shut down, many other circuit breakers tripped to the open position. The aircraft was a DC9-30, and the fault was only 1 single phase circuit breaker that had failed. No other fault light or bus xfer lights illuminated. No automatic xfer of electrical power occurred. There was no warning as it was a partial failure, even though most instruments on the left side had failed. The left AC bus failed, but only 1 phase circuit breaker failed. When that circuit breaker was replaced, the aircraft operated normally.

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Original NASA ASRS Text

Title: A DC9-30 FLYING IN ZID AIRSPACE, SUFFERS A PARTIAL ELECTRICAL FAILURE WITH NO INDICATIONS OF PWR LOSS. EMER IS DECLARED BECAUSE THE CAPT LOSES MOST OF HIS FLT INSTS.

Narrative: AFTER LEVELOFF AT FL350 WE STARTED TO GET SEVERAL UNRELATED SYS FAILURES. CIRCUIT BREAKERS STARTED POPPING AND AFTER 2-3 MINS THE L SIDE OF THE ACFT LOST MOST OF ITS ELECTRICAL PWR. LOST THE CAPT'S VOR AND RADIO AND SOON THEREAFTER, THE ATTITUDE INDICATOR. THE ELECTRICAL ABNORMALITIES CHKLIST WAS RAN BUT NO SYS FAILURES WERE INDICATED. WE DEDUCED WE HAD A PROB WITH THE L AC BUS BUT HAD NO 'BUS' FAILURE LIGHTS AND THE BUS DID NOT AUTO SWITCH TO THE R SIDE AS IT SHOULD HAVE. IT WAS VFR AND WE RETURNED TO DTW UNEVENTFULLY. IT MAY HAVE BEEN A DIFFERENT CASE HAD IT BEEN IFR. THE DC9 IS GETTING OLD AND ELECTRICAL FAILURES ARE MORE COMMON. WHAT IS DISTURBING IS THE WARNING AND AUTO SWITCHING SYS ARE NOT WORKING AS THEY SHOULD. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: RPTR STATED THAT THE FLT INSTS ON THE CAPT'S SIDE BEGAN TO FAIL WITHOUT INDICATIONS OF ANY ELECTRICAL PWR LOSS, SUCH AS THE XFER BUS ILLUMINATING OR ANY OTHER RED LIGHTS. WHEN THE DECISION WAS MADE TO RETURN TO POINT OF DEP, AN EMER WAS DECLARED. ONLY INSTS ON THE R SIDE KEPT WORKING. THERE WAS ONLY 1 CIRCUIT BREAKER THAT HAD TRIPPED, WHICH WAS A CIRCUIT BREAKER FOR A SINGLE PHASE OF A 3 PHASE GENERATOR. AFTER THE ACFT LANDED AND TAXIED TO THE GATE AND PARKED, AS THE ENGS WERE BEING SHUT DOWN, MANY OTHER CIRCUIT BREAKERS TRIPPED TO THE OPEN POS. THE ACFT WAS A DC9-30, AND THE FAULT WAS ONLY 1 SINGLE PHASE CIRCUIT BREAKER THAT HAD FAILED. NO OTHER FAULT LIGHT OR BUS XFER LIGHTS ILLUMINATED. NO AUTO XFER OF ELECTRICAL PWR OCCURRED. THERE WAS NO WARNING AS IT WAS A PARTIAL FAILURE, EVEN THOUGH MOST INSTS ON THE L SIDE HAD FAILED. THE L AC BUS FAILED, BUT ONLY 1 PHASE CIRCUIT BREAKER FAILED. WHEN THAT CIRCUIT BREAKER WAS REPLACED, THE ACFT OPERATED NORMALLY.

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.