What type of aircraft are subject to the minimum equipment list regulations?

The minimum equipment list (MEL) regulations apply specifically to certain types of aircraft operated under specific parts of the Federal Aviation Regulations (FAR). In this case, those are Part 121 and Part 135 operators. Part 121 typically governs scheduled air carriers while Part 135 applies to commuter and on-demand operations, including charter flights.

These regulations are designed to ensure that commercial operations can continue safely even if certain equipment is inoperative, provided that the operators comply with the MEL. The MEL details what equipment may remain inoperative and under what conditions the aircraft may still be operated.

In contrast, not all commercial aircraft are required to follow the MEL regulations; they primarily apply to those under Parts 121 and 135. Single-engine aircraft, gliders, and ultralights do not fall under these specific regulatory frameworks and, as such, do not have the same requirements regarding minimum equipment lists.