For overhaul maintenance, who publishes engine inspection procedures?

• A. Airframe manufacturer
• B. The airline operator
• C. Engine manufacturer
• D. Independent inspector

Answer: (C)

Engine overhaul inspection procedures come from the engine manufacturer because they own the engine’s design data and know the exact wear limits, inspection methods, and acceptance criteria that ensure the engine remains airworthy after being rebuilt. The OEM provides the authoritative manuals—like the Engine Maintenance Manual—that specify how to disassemble, inspect (including borescope and non-destructive testing methods), measure tolerances, and determine when parts must be repaired or replaced. Following these procedures ensures consistency across shops and compatibility with certification requirements. The airframe manufacturer handles procedures related to the aircraft structure, the airline operator may set operator-specific maintenance schedules, and independent inspectors verify compliance, but they do not publish the official engine-specific inspection procedures.