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A B747-400 in cruise diverted due to loss of #2 engine oil caused by the incomplete and improper accomplishment of the MEL special procedures for an engine driven hydraulic pump deferral.
| Attributes | |
| ACN | 397093 |
| Time | |
| Date | 199803 |
| Day | Sat |
| Local Time Of Day | 0001 To 0600 |
| Place | |
| Locale Reference | airport : zzz |
| State Reference | US |
| Altitude | agl bound lower : 0 agl bound upper : 0 |
| Environment | |
| Light | Night |
| Aircraft 1 | |
| Controlling Facilities | tracon : ont |
| Operator | common carrier : air carrier |
| Make Model Name | B747-400 |
| Operating Under FAR Part | Part 121 |
| Navigation In Use | Other Other |
| Flight Phase | other |
| Flight Plan | None |
| Person 1 | |
| Affiliation | company : air carrier |
| Function | other personnel other |
| Qualification | other other : other |
| ASRS Report | 397093 |
| Person 2 | |
| Affiliation | company : air carrier |
| Function | other personnel other |
| Qualification | other other : other |
| Events | |
| Anomaly | aircraft equipment problem : critical non adherence : published procedure non adherence : far |
| Independent Detector | aircraft equipment other aircraft equipment : unspecified other flight crewa other other : unspecified |
| Resolutory Action | none taken : detected after the fact |
| Consequence | Other |
| Supplementary | |
| Primary Problem | Aircraft |
| Air Traffic Incident | other |
Narrative:
I was given a job to inoperative the #2 hydraulic system. This included removing the #2 hydraulic pump. Using a kit is necessary to complete the job. I worked job using an MEL instruction sheet. Removed pump and separated lines to pump. Using kit supplied, I discovered either kit was incomplete or I had obtained wrong kit. Only 2 pieces of kit were usable. I obtained what I felt were the remaining caps and plugs to complete job. I didn't notice 2 lines in paperwork that said disconnect this line and use appropriate tees and caps. These lines didn't need to be broken to get the pump and lines disconnected. With kit being incomplete, I didn't see these 2 plugs. This MEL had no 'safety net' factors involved. I motored engine per MEL and found no leaks. Apparently, engine will not leak when motored, but did leak at altitude and under power and pressure. I'm not 100% sure about this, but have been told, 'might happen.' I failed to cap line, which would have prevented a leak.
Original NASA ASRS Text
Title: A B747-400 IN CRUISE DIVERTED DUE TO LOSS OF #2 ENG OIL CAUSED BY THE INCOMPLETE AND IMPROPER ACCOMPLISHMENT OF THE MEL SPECIAL PROCS FOR AN ENG DRIVEN HYD PUMP DEFERRAL.
Narrative: I WAS GIVEN A JOB TO INOP THE #2 HYD SYS. THIS INCLUDED REMOVING THE #2 HYD PUMP. USING A KIT IS NECESSARY TO COMPLETE THE JOB. I WORKED JOB USING AN MEL INSTRUCTION SHEET. REMOVED PUMP AND SEPARATED LINES TO PUMP. USING KIT SUPPLIED, I DISCOVERED EITHER KIT WAS INCOMPLETE OR I HAD OBTAINED WRONG KIT. ONLY 2 PIECES OF KIT WERE USABLE. I OBTAINED WHAT I FELT WERE THE REMAINING CAPS AND PLUGS TO COMPLETE JOB. I DIDN'T NOTICE 2 LINES IN PAPERWORK THAT SAID DISCONNECT THIS LINE AND USE APPROPRIATE TEES AND CAPS. THESE LINES DIDN'T NEED TO BE BROKEN TO GET THE PUMP AND LINES DISCONNECTED. WITH KIT BEING INCOMPLETE, I DIDN'T SEE THESE 2 PLUGS. THIS MEL HAD NO 'SAFETY NET' FACTORS INVOLVED. I MOTORED ENG PER MEL AND FOUND NO LEAKS. APPARENTLY, ENG WILL NOT LEAK WHEN MOTORED, BUT DID LEAK AT ALT AND UNDER PWR AND PRESSURE. I'M NOT 100% SURE ABOUT THIS, BUT HAVE BEEN TOLD, 'MIGHT HAPPEN.' I FAILED TO CAP LINE, WHICH WOULD HAVE PREVENTED A LEAK.
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.