Which document specifies the type of fuel that should be used in an airplane?

• A. The TCDS for that airplane.
• B. The aircraft registration certificate.
• C. The maintenance manual.
• D. The airworthiness directive.

Answer: (A)

Fuel type is defined by the aircraft’s official certification documentation. The Type Certificate Data Sheet lists the approved fuels for the engine installations and is the authoritative reference for what can be used in that airplane. It ties directly to the certification basis and limitations established when the aircraft was certified, so it’s the correct source to determine permitted fuels.

The other documents serve different roles. The registration certificate confirms ownership and nationality but not operating limits. The maintenance manual covers how to perform maintenance and may include fuel handling procedures, but it’s not the primary source for which fuels are approved. An airworthiness directive addresses a safety issue and required actions; it does not specify which fuel is allowed.