Maintenance technicians reported incomplete information in aircraft engine repair job cards as well as a breakdown in mechanic communication between shifts.
Synopsis
Maintenance technicians reported incomplete information in aircraft engine repair job cards as well as a breakdown in mechanic communication between shifts.
Narrative
Came into shift on Day 0 at XA:00; turn over from swing shift was that the aircraft was down to engine runs for fuel nozzle replacement on the number one engine. Went through paperwork to see what was left and proceeded. Sprayed down ducts in the core section with leak detectant. Aircraft was pushed outside and I proceeded with engine runs. Person A was in the cockpit with me and the other mechanics were downstairs watching the motor and looking it over between runs. Performed all tasks per job card and Aircraft Maintenance Manual (AMM); no abnormal readings inside the cockpit and the motor even passed the engine idle test and pneumatic engine on test performed through the Multi-function Flight Display (MFD). Mechanics downstairs did not see any leaks either so the engine was closed up and we started finalizing paperwork while the plane was towed to the line. At around XH:00 Day 1 we realized opposite side pressure (OSP) had not been done yet. Person A and I made our way down to the line to run both engines. During runs there was again no abnormal readings and both engines were operating in similar tolerances. The rest of shift proceeded as normal; clocked out at XK:30. At around XW:00 that night I was informed by a coworker that Aircraft X had an engine fire at takeoff around XL:33 that morning and did an in air return to field. Suggestion: I believe high power runs need to be added back into the job card for fuel nozzle changes. This may have been detected with high power runs that were previously removed from the job card.
Second reporter narrative
I arrived at work for my Day 0 shift at XA:00. Person B was the acting shift manager; Person C was the shift supervisor; Person D was my Crew Chief (CC); and Person A; Person E and Person F and Person G were my team mates assigned to work Aircraft X for the night. We were initially told by our CC Person D that swing was buttoning up some of the non-routines and overnight maintenance items but the Nozzle change was down to engine runs/operations checks. When we walked to the aircraft; the winglet changed was being buttoned up and swing shift was still working some seats in the interior. While those were happening; I took it upon myself to do a general visual inspection (GVI) of the engine to look for obvious signs of missing parts; loose parts and tight B-nuts. Even though there is a stamp for the installation of each component/part; and even a buyback from a different mechanic to verify the work; it is VERY common for me to find loose bolts; brackets; missing brackets; and even loose or uninstalled B-nuts after getting turn over from swings that the engine is 'completed and ready for runs'. In this particular instance all stamps were previously bought off; and the engine appeared to be complete. At the time I was not familiar with the components that are removed or installed on the RH side of Leap 1B engines for fuel nozzle changes. I did not look at the tube that was not installed correctly because of it hard to see mounting location; and was not aware that it gets removed/installed during its shop visit. Everything appeared normal; so we cleaned up the area and verified paperwork. We had a meeting to discuss who would be doing what role that night. I usually run the engines on the planes; but Person E was in that night and offered to run the engines. I volunteered to drive the TUG and push the plane back to the pad. I drove the tug over and my other team mates hooked up the tow bar and got everything ready. The steering bypass pin was missed and the towbar sheered its pin when we were half way out of the hangar. The manager Person B was next to the plane when this occurred. We immediately stopped; disconnected the towbar and printed the NLG inspection after shearpin. We completed the inspection with no findings. We then went on the hunt to find a tow bar because the one we sheared is the only one at the hangar. We eventually grabbed one from the line; after which we pushed the plane back to the pad without incident. Person F was going to accomplish the runs; Person E was the signalman/ Person A was in the right seat observing; and I was standing on the stairs at the L1 door to verbally notify Person F to cut the fuel when the motor was going to fog for the Leak check. After wet motor shut down; myself and Person E verified there were no fuel leaks. I looked at the left hand side of the motor and Person E looked at the right hand side of the motor. We then closed the engine thrust reversers (TRs) and fan cowls in prep for runs. I stood in the doorway of the cockpit to observe the engine indications during the runs. I observed no abnormal indications at any point. All tests were normal. Myself; Person A and Person E opened the TRs and looked for pneumatic leaks. I inspected the left side and Person E inspected the right side. When we were closing the cowls I briefly looked at Person E's side for obvious signs of leaks. The were no abnormal conditions or signs of leaks or overheating. I was not originally intending on doing the pneumatic checks myself as I am usually running the engines so I did not prep the motor myself for those checks. There was developer on the motor when I verified the leak check after runs; but I am not sure who put it on there. After closing out the nozzle maintenance; we towed the aircraft to the gate. There were still open overnight maintenance items/non-routines that were going to be turned over to days. After moving Aircraft X to the gate; we were told to bring back Aircraft Y to the hangar and startthe overnight maintenance on that plane. A culture of non-accountability exists in ZZZ which allows frequent escapes like this to go unchecked. Often times there are poor turnovers; paperwork errors; parts incorrectly installed or not at all. When things like this happen; it is often caught by other mechanics and corrected without being reported or the offending individual being aware that a mistake was made. Jobcards for the LEAP 1B engine can be confusing at times; and is very inconsistent in how it directs you to do maintenance. Sometimes bouncing you to an Aircraft Maintenance Manual (AMM) and back to a figure within the job card. Grave shift is often pushed to extremes to finish these fuel nozzle planes; or other planes after days and swings seems unable to accomplish maintenance within a reasonable time period. Even with Days/Swings working at a slower pace; graves shift consistently receives turnovers of planes that have been signed off up to engine runs; and are not fully assembled. Suggestions: Make job cards clear and concise. If AMTs are making suggestions to have job cards modified to be more clear or improved; those recommendations should be reviewed and adopted in a timely matter. When preparing to end a shift and get ready for turn over; a job should not be stopped halfway through a removal or an installation. Steps need to be completed to a stopping point. for example: if you're going to stab fuel nozzles; they need to be completely torqued and installed before the next shift. If you cannot get all the B nuts connected; or all the mounting bolts final torqued; do not start that process. A culture of accountability needs to be created that ensures when a stamp is missed the stamping individual is made aware of the issue. If a part is not installed correctly or missed the mechanic is made aware. From CC to mechanic and mechanic to mechanic.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.