Narrative:

I work for contracted maintenance performing on call maintenance on commercial airliners at ZZZ. I was contacted by abc maintenance control; to investigate an oil leak from the #2 engine on aircraft X. I was instructed to open the #2 engine nacelle cowling to facilitate locating the leak. This aircraft had come in the afternoon with a #3 recap main gear tire blistered in 4 places. I took this call and after notifying company of the tire's condition the flight was canceled and a tire assembly and socket was sent to ZZZ to change out the #3 wheel assembly. The next shift crew repositioned the aircraft to a remote pad; received the wheel assembly and completed the change. The crew arrived at the remote pad on the next morning for a non-revenue repositioning flight to ZZZ1 and wrote up the leak he noticed. After opening the #2 engine nacelle cowling I determined that the hydraulic edp (engine driven pump) was leaking hydraulic fluid from its case halves and I notified maintenance control. The controller informed me that they wanted me to remove the hydraulic edp from the #2 engine. That this was coming back to them and they could complete the change in ZZZ1. He stated that all I had to do was pull the pump install a blank-off plate to cover the hole and cap off the hydraulic fittings where the lines were removed that hooked up to the hydraulic edp. I located these larger parts in the fly away kit. While pulling the pump I didn't notice any oil when separating the pump from the gear box. The hydraulic lines had quick disconnect fittings and I used quick disconnect caps at the connectors. After I finished these tasks I informed maintenance control of exactly what I had done and that I was going to close the #2 engine nacelle cowl. I was given the go ahead and I was told next we would complete the logbook write-up. The logbook maintenance discrepancy read: #2 engine; oil leak. The corrective action/deferral that I was instructed to write read: continued operations per MEL. I was told that I had been following the (M) amm task noted in the MEL per maintenance control direction/instructions. The aircraft left ZZZ bound for ZZZ1 but diverted to ZZZ2 with loss of #2 engine oil. I thought that the gear box pad was dry and only needed a blank off plate. It required a spline plug to be inserted in the spline shaft. A part and step that I wasn't informed of. The amm task also called out for an engine run and leak check to be performed before closing the cowling. Another step omitted. I feel the remote pad/location; along with the crew on board waiting to leave. The fact that it was going right to company's maintenance facility; being a non revenue flight. All contributed to allowing myself to be persuaded to only follow the company maintenance control's instructions without having a copy of the amm task on hand during the task.

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Original NASA ASRS Text

Title: A CRJ-900 (CL600-2D24) ACFT #2 ENGINE HYD DRIVEN PUMP WAS REPLACED BY A CONTRACT MAINT PROVIDER UNDER DIRECTION OF CARRIER'S MAINT CONTROL. SUBSEQUENT LOSS OF ENG OIL IN FLIGHT; ACFT DIVERTED.

Narrative: I WORK FOR CONTRACTED MAINT PERFORMING ON CALL MAINT ON COMMERCIAL AIRLINERS AT ZZZ. I WAS CONTACTED BY ABC MAINT CTL; TO INVESTIGATE AN OIL LEAK FROM THE #2 ENG ON ACFT X. I WAS INSTRUCTED TO OPEN THE #2 ENG NACELLE COWLING TO FACILITATE LOCATING THE LEAK. THIS ACFT HAD COME IN THE AFTERNOON WITH A #3 RECAP MAIN GEAR TIRE BLISTERED IN 4 PLACES. I TOOK THIS CALL AND AFTER NOTIFYING COMPANY OF THE TIRE'S CONDITION THE FLT WAS CANCELED AND A TIRE ASSEMBLY AND SOCKET WAS SENT TO ZZZ TO CHANGE OUT THE #3 WHEEL ASSEMBLY. THE NEXT SHIFT CREW REPOSITIONED THE ACFT TO A REMOTE PAD; RECEIVED THE WHEEL ASSEMBLY AND COMPLETED THE CHANGE. THE CREW ARRIVED AT THE REMOTE PAD ON THE NEXT MORNING FOR A NON-REVENUE REPOSITIONING FLT TO ZZZ1 AND WROTE UP THE LEAK HE NOTICED. AFTER OPENING THE #2 ENG NACELLE COWLING I DETERMINED THAT THE HYD EDP (ENG DRIVEN PUMP) WAS LEAKING HYD FLUID FROM ITS CASE HALVES AND I NOTIFIED MAINT CTL. THE CTLR INFORMED ME THAT THEY WANTED ME TO REMOVE THE HYD EDP FROM THE #2 ENG. THAT THIS WAS COMING BACK TO THEM AND THEY COULD COMPLETE THE CHANGE IN ZZZ1. HE STATED THAT ALL I HAD TO DO WAS PULL THE PUMP INSTALL A BLANK-OFF PLATE TO COVER THE HOLE AND CAP OFF THE HYD FITTINGS WHERE THE LINES WERE REMOVED THAT HOOKED UP TO THE HYD EDP. I LOCATED THESE LARGER PARTS IN THE FLY AWAY KIT. WHILE PULLING THE PUMP I DIDN'T NOTICE ANY OIL WHEN SEPARATING THE PUMP FROM THE GEAR BOX. THE HYD LINES HAD QUICK DISCONNECT FITTINGS AND I USED QUICK DISCONNECT CAPS AT THE CONNECTORS. AFTER I FINISHED THESE TASKS I INFORMED MAINT CTL OF EXACTLY WHAT I HAD DONE AND THAT I WAS GOING TO CLOSE THE #2 ENG NACELLE COWL. I WAS GIVEN THE GO AHEAD AND I WAS TOLD NEXT WE WOULD COMPLETE THE LOGBOOK WRITE-UP. THE LOGBOOK MAINT DISCREPANCY READ: #2 ENG; OIL LEAK. THE CORRECTIVE ACTION/DEFERRAL THAT I WAS INSTRUCTED TO WRITE READ: CONTINUED OPS PER MEL. I WAS TOLD THAT I HAD BEEN FOLLOWING THE (M) AMM TASK NOTED IN THE MEL PER MAINT CTL DIRECTION/INSTRUCTIONS. THE ACFT LEFT ZZZ BOUND FOR ZZZ1 BUT DIVERTED TO ZZZ2 WITH LOSS OF #2 ENG OIL. I THOUGHT THAT THE GEAR BOX PAD WAS DRY AND ONLY NEEDED A BLANK OFF PLATE. IT REQUIRED A SPLINE PLUG TO BE INSERTED IN THE SPLINE SHAFT. A PART AND STEP THAT I WASN'T INFORMED OF. THE AMM TASK ALSO CALLED OUT FOR AN ENG RUN AND LEAK CHK TO BE PERFORMED BEFORE CLOSING THE COWLING. ANOTHER STEP OMITTED. I FEEL THE REMOTE PAD/LOCATION; ALONG WITH THE CREW ON BOARD WAITING TO LEAVE. THE FACT THAT IT WAS GOING RIGHT TO COMPANY'S MAINT FACILITY; BEING A NON REVENUE FLT. ALL CONTRIBUTED TO ALLOWING MYSELF TO BE PERSUADED TO ONLY FOLLOW THE COMPANY MAINT CTL'S INSTRUCTIONS WITHOUT HAVING A COPY OF THE AMM TASK ON HAND DURING THE TASK.

Data retrieved from NASA's ASRS site as of January 2009 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.