A Line Mechanic reports ongoing maintenance practice by his Air Carrier of having mechanics run out to their ERJ-140 aircraft and wipe down any engine cowling with oil leakage residue; instead of properly trouble shooting the cause of the leak.
Synopsis
A Line Mechanic reports ongoing maintenance practice by his Air Carrier of having mechanics run out to their ERJ-140 aircraft and wipe down any engine cowling with oil leakage residue; instead of properly trouble shooting the cause of the leak.
Narrative
Company ERJ-140 aircraft X was given a special request work callout by [Maintenance] Planning (Maintenance Operations Control) to Remove and Replace (R/R) fuel pump metering unit (FPMU) carbon seal. I was given the task of running the engines after installation of carbon seal to ensure that there were no leaks found. We (the Inspector and I) found residual leakage and attributed the oil dripping from the thrust reverser panels afterwards; to be poor cleaning of cowling prior to the runs. I signed the logbook and the Inspector signed the Airworthiness Release.I started to watch the oil leaks on said cowling on subsequent flights of Aircraft X for the next few days. I noticed on several days since the runs that my fellow mechanics would rush out to the aircraft upon its arrival to wipe down the cowling as soon as possible to remove any trace of oil leaks. Consequently; the crew never saw anything and did not report any discrepancies in the logbook. I voiced my concern and objection to my fellow co-workers but received a deaf ear. NO ONE wanted to ground the aircraft and NO ONE wanted to open the cowling to investigate the ongoing UNCORRECTED and UNDOCUMENTED discrepancy. A fellow co-worker then shared with me that the line crews are doing the same with Aircraft Y. Needless to say; words fail to express my disbelief and disappointment at this situation. Today; I was determined to ground Aircraft X upon an inspection finding but did not get a chance to do so due to [aircraft] routing.
NASA callback
Reporter stated they were so frustrated and upset watching other mechanics run out and wipe down the engine cowlings of any oil leakage that he and another Mechanic decided to run #1 engine again on aircraft X several days later. They isolated the source of the continuing oil leakage to come from the starter mount by 'bagging' the component drain lines. He has noticed their Rolls Royce (Allison) engines seem to leak a lot at the air turbine starter magnetic carbon seal mount to the accessory gearbox. The fuel pump metering units (FPMU) also leak oil from a slightly different carbon seal at the FPMU to gearbox mount.Reporter stated carbon seals are installed on the accessory gearbox side where components are attached to the gearbox; on the air turbine starter and FPMU. The carbon seal he changed on # 1 engine starter stopped the oil leakage on the cowling. Carbon seals can only be changed one or two times and then the #4 main bearing has to be boroscoped for condition with the engine generally having to be removed.
Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.