Oil Debris MEL

[punkalouver]

An interesting MEL. Never heard of this one before.....

"an XXX Airlines A220-300, was conducting flight Flight 774 from AAA to BBB
The aircraft was being operated with a deferred MEL for the oil debris above limits on the right- hand engine. After departure, the advisory message ''oil debris'' for the right-hand engine illuminated on the EICAS. While in cruise flight at FL350, the flight crew received a repeated but intermittent, right-hand ''engine vibration'' caution message, along with a right-hand ''Fan VIB'' indication. The flight crew completed the abnormal checklist, discussed the situation with dispatch and maintenance control and elected to continue the flight towards BBB. In the vicinity of CCC, the right-hand engine failed and shut down automatically. The system attempted an auto-relight as designed but failed. The flight crew completed the checklist, declared a MAYDAY with ATC and elected to divert to CCC where it landed without further incident. Maintenance at CCC is investigating."

[alf5071h]

Never heard of this one before.....

Chip detector ?
Allowable particle count - keep monitoring.
Language is a wonderful tool, except where it is distorted (misused) by national culture, education, etc.

[Tom Sawyer]

Can also have the message due to a fault with Electrical Master Chip Detector and/or indication system giving a false indication which is in the MEL for dispatch with conditions. Hopefully before the deferral was raised an inspection of the EMCD had been carried out, but even so the debris found may have been within AMM limits, particularly if the engine was relatively new?

[ShyTorque]

I was once faced with a similar situation on a twin engined helicopter. Maintenance had told me they had done extensive diagnostic checks on one of its engines, which had thrown up repeated “chip” warnings on a previous flight. I was briefed by the duty engineering manager that they now suspected it to be a wiring fault causing spurious warnings because there had been no sign of any debris found on the detector and not to be unduly concerned if it recurred. They had carried out an oil drain and flush and extensive ground runs then it was put back on the line. Sure enough, during my flight it put up a chip light. As I was unable to divert anywhere for a single engined running landing I put it to idle and returned to base, bringing it up again a few minutes later for the landing.

I reported the chip light. Two days later I was issued with a formal written warning for not shutting the engine down because it had made a lot of metal in a very short time. The a$$#@/e duty engineering manager took very large steps backwards, refusing to back me up at all.

One of life’s lessons learned.