Three Maintenance Controllers report on their involvement with a B737-700 that had previously diverted with an in-flight shutdown due to an oil filter by-pass indication. After oil filter changes and checking chip detectors; aircraft was released; but did not have the AMM Maintenance reference for the chip detectors in the MEL deferral sign-off.
Synopsis
Three Maintenance Controllers report on their involvement with a B737-700 that had previously diverted with an in-flight shutdown due to an oil filter by-pass indication. After oil filter changes and checking chip detectors; aircraft was released; but did not have the AMM Maintenance reference for the chip detectors in the MEL deferral sign-off.
Narrative
Maintenance Control was notified by Dispatch that a B737-700 aircraft had a #2 engine oil filter bypass light illuminated at all power settings and was going to divert. Once landed; Contract Maintenance was called to inspect the oil filter. Minor debris was found in the filter and Engine Engineering was notified by phone. Pictures were then forwarded to them. The Engine Engineer said that the engine had only been installed for 55 days and that the debris was shop debris. They suggested changing the filter and checking the chip detectors. As far as I know the Maintenance Controller had the Contract Mechanic do both. They ran the engine with the new filter and checked them a second time and they were clean from what I was told. I was also told the light remained illuminated the whole time even after the filter was changed. I was the Maintenance Controller Lead and was not involved in the event after the initial information was given to me. The system was MEL'ed and the aircraft released. The aircraft continued to destination with the light still illuminated. Maintenance replaced the oil filter bypass switch and cleared the MEL. They checked the chip detectors again found debris on one of them. The debris was different from the previous debris; but was unidentifiable. Engine Engineering had them send the debris to the Lab for analysis. I was told the next day that they ended up replacing the engine.
Second reporter narrative
Flight experienced in-flight shutdown (ISD) of #2 engine due to oil filter bypass indication. Maintenance personnel were involved in the process. In summary; Contract Maintenance inspected and replaced the scavenge oil filter in preparation for MEL; minor metal was found. Engine Engineering was contacted and sent digital pictures of the metal. He recommended filter replacement and deferral of the Indication system. Maintenance Control went further with troubleshooting. The filter was replaced; the engine run at high power for at least five minutes. The filter was again inspected; along with the chip detectors - they were clean. The Flight departed with the MEL applied. During the confusion of several Controllers being involved; the chip detector AMM reference was possibly not sent. The aircraft arrived after the metal (debris) was sent to a Lab; Engine Engineering determined it was prudent to replace the engine.
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Source: NASA Aviation Safety Reporting System (public domain). Reports are voluntary submissions and are not verified by NASA.