Narrative:

This is an oversight associated with applying an MEL after a generator failure at the ramp prior to departure. While taxiing away from the parking spot on the ramp, the flight engineer placed all 3 generators on line. #2 generator failed to come on line, but in this process also tripped the generator and field breakers and illuminated the 'differential fault' light on the flight engineer's auxiliary annunciator panel. Since this was an indication of a possible short or merely a transient glitch due to placing the generator on line, I returned to the ramp without accomplishing all abnormal checklist items. At the ramp parking place we shut down engines and reviewed the MEL. Determining that MEL 'generators and constant speed drive units' was most appropriate for this malfunction. The MEL showed maintenance and operational, (M) (O), items to be accomplished. I reviewed the block section at the beginning of the section and briefly, the accompanying 2 pages of verbiage. The contract mechanic had left the area when we were pushed back, so I contacted maintenance control for our company by phone. Without the MEL book in hand I asked them to verify that I could be dispatched 2 generators and with all busses powered with placards applied to generator breaker and airconditioning pack cooling fan circuit breaker pulled (a high electric load item). I was not informed nor did I notice that the MEL calls for disconnecting the constant speed drive (CSD) for the generator or checking constant speed drive oil level prior to continuing. I did enter the discrepancy and entered appropriate maintenance control reference numbers to logbook as dictated by policy. At the next stop a company mechanic determined it was a transient fault and reset the generator to normal operation.

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Original NASA ASRS Text

Title: A B727 FREIGHTER RETURNS TO THE RAMP WITH A #2 GENERATOR PROB. ACFT LEAVES AFTER IMPROPER ANALYSIS OF PROB AND FAILURE TO COMPLY WITH ALL OF THE PROVISIONS OF THE MEL.

Narrative: THIS IS AN OVERSIGHT ASSOCIATED WITH APPLYING AN MEL AFTER A GENERATOR FAILURE AT THE RAMP PRIOR TO DEP. WHILE TAXIING AWAY FROM THE PARKING SPOT ON THE RAMP, THE FE PLACED ALL 3 GENERATORS ON LINE. #2 GENERATOR FAILED TO COME ON LINE, BUT IN THIS PROCESS ALSO TRIPPED THE GENERATOR AND FIELD BREAKERS AND ILLUMINATED THE 'DIFFERENTIAL FAULT' LIGHT ON THE FE'S AUX ANNUNCIATOR PANEL. SINCE THIS WAS AN INDICATION OF A POSSIBLE SHORT OR MERELY A TRANSIENT GLITCH DUE TO PLACING THE GENERATOR ON LINE, I RETURNED TO THE RAMP WITHOUT ACCOMPLISHING ALL ABNORMAL CHKLIST ITEMS. AT THE RAMP PARKING PLACE WE SHUT DOWN ENGS AND REVIEWED THE MEL. DETERMINING THAT MEL 'GENERATORS AND CONSTANT SPD DRIVE UNITS' WAS MOST APPROPRIATE FOR THIS MALFUNCTION. THE MEL SHOWED MAINT AND OPERATIONAL, (M) (O), ITEMS TO BE ACCOMPLISHED. I REVIEWED THE BLOCK SECTION AT THE BEGINNING OF THE SECTION AND BRIEFLY, THE ACCOMPANYING 2 PAGES OF VERBIAGE. THE CONTRACT MECH HAD LEFT THE AREA WHEN WE WERE PUSHED BACK, SO I CONTACTED MAINT CTL FOR OUR COMPANY BY PHONE. WITHOUT THE MEL BOOK IN HAND I ASKED THEM TO VERIFY THAT I COULD BE DISPATCHED 2 GENERATORS AND WITH ALL BUSSES POWERED WITH PLACARDS APPLIED TO GENERATOR BREAKER AND AIRCONDITIONING PACK COOLING FAN CIRCUIT BREAKER PULLED (A HIGH ELECTRIC LOAD ITEM). I WAS NOT INFORMED NOR DID I NOTICE THAT THE MEL CALLS FOR DISCONNECTING THE CONSTANT SPD DRIVE (CSD) FOR THE GENERATOR OR CHKING CONSTANT SPD DRIVE OIL LEVEL PRIOR TO CONTINUING. I DID ENTER THE DISCREPANCY AND ENTERED APPROPRIATE MAINT CTL REF NUMBERS TO LOGBOOK AS DICTATED BY POLICY. AT THE NEXT STOP A COMPANY MECH DETERMINED IT WAS A TRANSIENT FAULT AND RESET THE GENERATOR TO NORMAL OP.

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.