Narrative:

I was informed that aircraft had an oil leak caused by an adapter left in the N2 drive pad. This is what happened to the best of my recollection. While performing a repair on the #1 engine egt trends which included a #1 engine borescope; technician #1; technician #2 and myself were complying with multiple tasks on the engine along with other workload items on the aircraft. The aircraft arrived and was moved to the hangar. While I was complying with other tasks; I loaned technician #2 my ratchet; extension and 3/4 inch adaptor (black in color) to rotate the motor. While I was complying with an egt test on the same motor; I saw my ratchet in my tool box and did not notice the adapter missing; or paid much attention to it while doing the egt test. Upon completion of the borescope; the borescope plugs and N2 rotor rotation pad cover was being installed referencing the issued work card and applicable maintenance manual. The N2 rotor rotation cover was installed by technician #2 and apparently inadvertently leaving the 3/4 inch drive adapter installed in the drive pad. The time at this point was approximately XA00. After all other tasks were complete; the aircraft was taken and an idle power leak check was performed with no leaks and no visible faults; a power run was completed as well to complete the repair. On a subsequent flight; the subject engine experienced a loss of oil quantity and pressure. Investigation determined the cause to be a whole worn through the N2 rotor pad cover consistent with the drive tool used to rotate the engine when a borescope inspection is performed. Callback conversation with reporter revealed the following information: the reporter stated there had never been a dedicated N2 pad drive socket and most technicians just used a .75 inch socket. The socket and short extension were used to drive the N2 rotor for borescoping. The job card has the drive pad cover installation as an inspection item after the borescoping is complete. This socket remained on the drive spline and with the engine running damaged the drive pad cover causing the loss of oil. The company has now changed the job card that requires a special tool that must be checked out of the tool crib that is long enough to prevent installing the cover plate if not removed. The card also changed the inspection procedure that requires the inspector to check the drive spline before the cover is installed and check the cover plate after installation.

Related reports:

Google
 

Original NASA ASRS Text

Title: A B737-500 HAD AN ENGINEERING ORDER FOR AL ENG BORESCOPE. N2 DRIVE PAD HAD AN IMPROPER TOOL INSERTED AND NEVER REMOVED. CAUSED LOSS OF ENG OIL PRESSURE AND QUANTITY.

Narrative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

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.