If approached to replace an engine with a different make and horsepower rating, what document should you first consult?

When considering replacing an engine with a different make and horsepower rating, the first document to consult is the type certificate data sheet (TCDS). The TCDS provides crucial information regarding the aircraft's design and its approved modifications, including specifics about the engines that are certified for use with that particular aircraft model.

The TCDS outlines the engine makes and models that have been tested and found to operate safely with the airframe, ensuring that any replacement engine complies with necessary standards and regulations. If a new engine is not listed in the TCDS, it may not be approved for use, which can lead to legal and safety concerns.

Other documents, like the manufacturer's maintenance manual or supplemental type certificates summary, are useful in their own right but do not specifically address the certification status of alternative engines for the aircraft. The maintenance advisory guide, while informative, also does not hold the regulatory authority of the TCDS when it comes to engine compatibility and safety. Therefore, for engine replacement considerations, the TCDS is the essential document to review first.