During a scheduled inspection, a mechanic removes the magnetic chip detector plug from a turbine engine's oil sump and finds fine gray metallic fuzz adhering to the magnet. What is the appropriate next step?
- AImmediately reject the engine and remove it for teardown
- BClean the detector and compare the debris to the manufacturer's acceptable fuzz/chip criteria before making an airworthiness determination
- CReplace only the oil filter and return the engine to service without further action
- DDisregard the fuzz since chip detectors only detect fuel contamination, not oil debris
Show answer & explanationAnswer & explanation
Correct answer: B. Clean the detector and compare the debris to the manufacturer's acceptable fuzz/chip criteria before making an airworthiness determination
Fine metallic fuzz on a chip detector can be a normal byproduct of break-in wear, while larger chips or flakes indicate abnormal internal wear or impending failure. Manufacturer maintenance manuals provide specific criteria distinguishing acceptable fuzz from actionable chips, so the mechanic must compare findings to those criteria before deciding on further action.
Why the other options are wrong
- A. Immediate teardown is not warranted for normal fine fuzz without manufacturer guidance indicating a problem.
- C. Ignoring the debris and only servicing the filter overlooks a potential early indication of internal engine wear.
- D. Chip detectors are installed in oil systems specifically to catch metallic wear debris, not fuel contamination.
Magnetic Chip Detector
A magnetized plug in the oil system that collects ferrous wear debris, used to monitor internal engine condition; fine fuzz is often normal while larger chips signal a developing problem.
- Located in oil sump/scavenge lines
- Fine fuzz can be normal wear
- Large chips/flakes indicate abnormal wear
- Findings must be compared to manufacturer criteria
Memory trick: Fuzz is fine, flakes are trouble