Powerplant Inspection, Maintenance, Troubleshooting, and Testing
Domain 8 tests planned inspection, condition monitoring, troubleshooting, and return-to-service testing.
Inspection and testing
- Required inspections include annual and 100-hour inspections, progressive inspections, and AD-mandated inspections.
- A differential compression test compares leakage at TDC; listen at exhaust, intake, crankcase, and adjacent cylinders.
- Oil analysis, borescope, filter cutting, and engine monitor data support condition-based maintenance.
- Run-up checks magnetos, prop cycle, idle, acceleration, and power; record findings.
Troubleshooting
- Use system knowledge and a logical sequence: verify symptom, isolate by test, inspect, repair, retest.
- Do not replace parts without evidence; use wiring diagrams and maintenance manuals.
- After maintenance, a return-to-service test may include leak checks and operational checks.
Worked example
A cylinder checks 58/80 with air escaping at the exhaust. The reading is below the common 60/80 minimum, and exhaust leakage points to the exhaust valve or seat. The reasoning is to locate the leak path before condemning the cylinder; intake leakage points to the intake valve, crankcase leakage to rings, and adjacent-cylinder leakage to a head gasket or crack.
Traps
Passing an engine because it runs smoothly; confusing AD compliance with a service bulletin recommendation; signing off without an operational check; ignoring repetitive squawks; using automotive test equipment.