Responsibility for airworthiness

This regulation establishes that Part 121 air carriers (airlines) are ultimately responsible for keeping their aircraft airworthy and ensuring all maintenance is done properly according to their maintenance manual and FAA regulations. This covers everything from the airframe and engines to propellers, appliances, emergency equipment, and individual parts.

Importantly, while airlines can contract out maintenance work to repair stations or other organizations, they cannot contract away their responsibility. The airline remains accountable even when someone else turns the wrenches. If contracted maintenance is done incorrectly or an aircraft flies in an unairworthy condition, the FAA holds the certificate holder responsible, not just the maintenance provider.

In practice, this means airlines must carefully oversee any maintenance they outsource, maintain proper documentation, and ensure all work meets regulatory standards. The buck stops with the certificate holder's management.

*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.*