Narrative:

Leveled off at FL350 over rod VOR. Got a radio fan, GPWS and flight recorder fail light. A min or so later #1 VHF and #1 VOR failed, and 3 fuel boost pump circuit breakers popped. Told ZID we had electrical problems and needed to return to dtw. Then the captain's ADI and CDI failed. Declared an emergency. On descent into dtw found 1 left AC bus circuit breaker popped, reset circuit breaker and got captain's instruments and #1 radios back, did not reset any other circuit breakers. Radio fan, GPWS, and flight recorder fail lights remained on. Never got any electrical fail lights (ie, generator off, AC bus off, etc). Generator voltage and frequencys were normal, though we surmised we had a left generator or left bus failure of some sort. Returned to dtw, landing normal. Did not require emergency equipment as flight instrument were back to normal. At the gate when aircraft's engines were shut down and APU accepted power, 11 more circuit breakers popped. Maintenance thought it might be a single phase problem with the left generator and that might be why the generator never tripped off and we never got any electrical fail indications. Callback conversation with reporter revealed the following information: the captain added that the maintenance supervisor said that the generators are 3 phase motors and with one phase defective the circuit breakers may not have sensed any fault. It might not affect any proper reading on the voltage or frequency meters either. The captain called maintenance the next morning and was told by someone else that it might have been a bad circuit breaker, location or function not mentioned. Captain felt it was more than that. This captain had another case of an electrical failure on a DC9 3 yrs ago wherein a left generator fault affected the entire aircraft's electrical system when the xtie operation shut down the entire system. Captain was not clear on when the checklist was performed. Since there was no AC/dc busses off the only thing to accomplish was to check for popped circuit breakers and to insure that the xtie switch is in the automatic position. This was an insidious, creeping loss of electrical circuits that started with the loss of one of the engine EPR gauges at leveloff. The captain reported this latest event to his company who in turn reports to the FAA. A copy was sent to the union safety department. He didn't know if the aircraft manufacturer was keyed into this latest scenario.

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Original NASA ASRS Text

Title: A DC9-30 IS MANDATED TO RETURN TO DTW AFTER LOSING A SERIES OF CRITICAL ITEMS INCLUDING THE CAPT'S #1 VHF, #1 VOR, HIS ADI AND HIS CDI. DURING DSCNT ONE LEFT AC BUS CIRCUIT BREAKER WAS RESET WHICH RESTORED THE CAPT'S INSTS AND RADIOS.

Narrative: LEVELED OFF AT FL350 OVER ROD VOR. GOT A RADIO FAN, GPWS AND FLT RECORDER FAIL LIGHT. A MIN OR SO LATER #1 VHF AND #1 VOR FAILED, AND 3 FUEL BOOST PUMP CIRCUIT BREAKERS POPPED. TOLD ZID WE HAD ELECTRICAL PROBS AND NEEDED TO RETURN TO DTW. THEN THE CAPT'S ADI AND CDI FAILED. DECLARED AN EMER. ON DSCNT INTO DTW FOUND 1 L AC BUS CIRCUIT BREAKER POPPED, RESET CIRCUIT BREAKER AND GOT CAPT'S INSTS AND #1 RADIOS BACK, DID NOT RESET ANY OTHER CIRCUIT BREAKERS. RADIO FAN, GPWS, AND FLT RECORDER FAIL LIGHTS REMAINED ON. NEVER GOT ANY ELECTRICAL FAIL LIGHTS (IE, GENERATOR OFF, AC BUS OFF, ETC). GENERATOR VOLTAGE AND FREQS WERE NORMAL, THOUGH WE SURMISED WE HAD A L GENERATOR OR L BUS FAILURE OF SOME SORT. RETURNED TO DTW, LNDG NORMAL. DID NOT REQUIRE EMER EQUIP AS FLT INST WERE BACK TO NORMAL. AT THE GATE WHEN ACFT'S ENGS WERE SHUT DOWN AND APU ACCEPTED PWR, 11 MORE CIRCUIT BREAKERS POPPED. MAINT THOUGHT IT MIGHT BE A SINGLE PHASE PROB WITH THE L GENERATOR AND THAT MIGHT BE WHY THE GENERATOR NEVER TRIPPED OFF AND WE NEVER GOT ANY ELECTRICAL FAIL INDICATIONS. CALLBACK CONVERSATION WITH RPTR REVEALED THE FOLLOWING INFO: THE CAPT ADDED THAT THE MAINT SUPVR SAID THAT THE GENERATORS ARE 3 PHASE MOTORS AND WITH ONE PHASE DEFECTIVE THE CIRCUIT BREAKERS MAY NOT HAVE SENSED ANY FAULT. IT MIGHT NOT AFFECT ANY PROPER READING ON THE VOLTAGE OR FREQ METERS EITHER. THE CAPT CALLED MAINT THE NEXT MORNING AND WAS TOLD BY SOMEONE ELSE THAT IT MIGHT HAVE BEEN A BAD CIRCUIT BREAKER, LOCATION OR FUNCTION NOT MENTIONED. CAPT FELT IT WAS MORE THAN THAT. THIS CAPT HAD ANOTHER CASE OF AN ELECTRICAL FAILURE ON A DC9 3 YRS AGO WHEREIN A L GENERATOR FAULT AFFECTED THE ENTIRE ACFT'S ELECTRICAL SYS WHEN THE XTIE OP SHUT DOWN THE ENTIRE SYS. CAPT WAS NOT CLR ON WHEN THE CHKLIST WAS PERFORMED. SINCE THERE WAS NO AC/DC BUSSES OFF THE ONLY THING TO ACCOMPLISH WAS TO CHK FOR POPPED CIRCUIT BREAKERS AND TO INSURE THAT THE XTIE SWITCH IS IN THE AUTO POS. THIS WAS AN INSIDIOUS, CREEPING LOSS OF ELECTRICAL CIRCUITS THAT STARTED WITH THE LOSS OF ONE OF THE ENG EPR GAUGES AT LEVELOFF. THE CAPT RPTED THIS LATEST EVENT TO HIS COMPANY WHO IN TURN RPTS TO THE FAA. A COPY WAS SENT TO THE UNION SAFETY DEPT. HE DIDN'T KNOW IF THE ACFT MANUFACTURER WAS KEYED INTO THIS LATEST SCENARIO.

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.