Purpose and definition

This regulation establishes the foundation for Subpart BB, which governs how Part 121 air carriers must maintain their aircraft's airworthiness over time. It requires certificate holders to actively support continued airworthiness rather than simply following an initial maintenance program.

In practical terms, this means airlines must stay current with evolving safety requirements throughout an aircraft's service life. The regulation specifically mentions three key responsibilities: updating maintenance programs as needed, implementing manufacturer-mandated design changes, and incorporating revised maintenance instructions from the aircraft manufacturer.

This matters because aircraft don't remain static—manufacturers discover issues, issue service bulletins, and update maintenance procedures based on fleet experience. This regulation ensures airlines can't simply stick with their original maintenance program but must evolve their practices to reflect new safety information and requirements. It's the legal basis for requiring airlines to implement airworthiness directives, service bulletins, and other continuing airworthiness improvements.

*This is a plain-English summary for study only. The official 14 CFR text on this page is controlling — always read the current regulation and consult a CFI.*