Which of the following contains approved data for performing a major repair to an aircraft engine?

• A. Airline's manual
• B. Manufacturer's maintenance instructions when FAA approved.
• C. Service bulletins
• D. Operator's manual

Answer: (B)

Approved data are the maintenance instructions that the FAA has reviewed and authorized for use on a specific engine. For a major repair, you must follow data that are FAA-approved, and the most reliable source for that is the engine manufacturer’s maintenance instructions when they have received FAA approval. These documents provide the exact repair procedures, tolerances, and limits tailored to that engine. Other sources like an airline’s manual or an operator’s manual aren’t automatically FAA-approved repair data, and service bulletins are only considered approved data if the FAA has mandated them or they’re incorporated by an AD. So the manufacturer’s maintenance instructions, when FAA approved, are the valid source for performing a major engine repair.