Narrative:

Shortly after my lunch break, quality control told me that they were done performing the borescope. Quality control informed me that the left and right side spark igniters and the S18 low pressure turbine stage 1 nozzle borescope plug were ready to go back in and were laying up inside the core cowl with my tools that they had used. So, according to my maintenance manual, I applied graphite grease to the threads of the S18 plug, installed it, then tightened the plug to 60 pound-inches and lock-wired it. I then installed the left and right spark igniters and my lead helped me perform the igniter chkout. My lead then went to inform quality control that the task of installation was complete and therefore ready for their final quality control chkout. Shortly afterwards, my lead then informed me that quality control had completed their final chkout and was ready for me to close the engine cowls and core cowls when I was able to. Then we both went down to close the engine cowls and core cowls. The air carrier non routine card stated: accomplished a one-time borescope inspection of the hpt nozzle leading edges. I performed everything required as an a&P mechanic per that non routine card. The first flight of the day aircraft xyz, #2 engine lost oil pressure and oil quantity. Engine was shut down in-flight and returned. They found the gear box access plate removed.

Google
 

Original NASA ASRS Text

Title: A B737-300 WAS DISPATCHED IN NON COMPLIANCE WITH #2 ENG CORE ENG ROTATION PAD MISSING FROM THE ACCESSORY GEAR BOX INCURRING A LOSS OF OIL AND ENG SHUTDOWN.

Narrative: SHORTLY AFTER MY LUNCH BREAK, QUALITY CTL TOLD ME THAT THEY WERE DONE PERFORMING THE BORESCOPE. QUALITY CTL INFORMED ME THAT THE L AND R SIDE SPARK IGNITERS AND THE S18 LOW PRESSURE TURBINE STAGE 1 NOZZLE BORESCOPE PLUG WERE READY TO GO BACK IN AND WERE LAYING UP INSIDE THE CORE COWL WITH MY TOOLS THAT THEY HAD USED. SO, ACCORDING TO MY MAINT MANUAL, I APPLIED GRAPHITE GREASE TO THE THREADS OF THE S18 PLUG, INSTALLED IT, THEN TIGHTENED THE PLUG TO 60 LB-INCHES AND LOCK-WIRED IT. I THEN INSTALLED THE L AND R SPARK IGNITERS AND MY LEAD HELPED ME PERFORM THE IGNITER CHKOUT. MY LEAD THEN WENT TO INFORM QUALITY CTL THAT THE TASK OF INSTALLATION WAS COMPLETE AND THEREFORE READY FOR THEIR FINAL QUALITY CTL CHKOUT. SHORTLY AFTERWARDS, MY LEAD THEN INFORMED ME THAT QUALITY CTL HAD COMPLETED THEIR FINAL CHKOUT AND WAS READY FOR ME TO CLOSE THE ENG COWLS AND CORE COWLS WHEN I WAS ABLE TO. THEN WE BOTH WENT DOWN TO CLOSE THE ENG COWLS AND CORE COWLS. THE ACR NON ROUTINE CARD STATED: ACCOMPLISHED A ONE-TIME BORESCOPE INSPECTION OF THE HPT NOZZLE LEADING EDGES. I PERFORMED EVERYTHING REQUIRED AS AN A&P MECH PER THAT NON ROUTINE CARD. THE FIRST FLT OF THE DAY ACFT XYZ, #2 ENG LOST OIL PRESSURE AND OIL QUANTITY. ENG WAS SHUT DOWN INFLT AND RETURNED. THEY FOUND THE GEAR BOX ACCESS PLATE REMOVED.

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.