Which of the following are FAA-approved data: service letters, service bulletins, instructions for continued airworthiness, ADs, or TCDSs?

• A. Service letters are FAA-approved data.
• B. Service bulletins are FAA-approved data.
• C. ADs and TCDSs are approved by the FAA.
• D. Instructions for continued airworthiness are FAA-approved data.

Answer: (C)

FAA-approved data are the official, legally enforceable sources that specify how an aircraft must be maintained and operated. Airworthiness Directives are directives issued by the FAA to correct unsafe conditions and they require mandatory compliance within specified time frames. Type Certificate Data Sheets list the design data approved by the FAA for a product (aircraft, engine, propeller) and define the approved configuration and operating limits. These two are the primary FAA-approved data that pilots and mechanics rely on for compliance and airworthiness.

Other documents like service letters and service bulletins are issued by the manufacturer and provide information, recommendations, or procedures, but they do not carry FAA approval or enforceability on their own. Instructions for Continued Airworthiness are guidance from the manufacturer about maintaining the product but are not, by themselves, FAA-approved data in the same way as ADs and TCDSs.