Equipment interchange: Domestic and flag operations

This regulation governs equipment interchange agreements, where one Part 121 carrier operates aircraft owned or leased by another carrier. Before beginning such operations, the operating certificate holder must demonstrate several things to the FAA:

All crew, dispatchers, and maintenance personnel must be properly trained on the specific aircraft and equipment they'll be working with, including communications, dispatch, and maintenance procedures. Flight crews and dispatchers must meet route and airport qualifications for the operations they'll conduct.

Critically, the interchanged aircraft must have essentially similar cockpit layouts—particularly flight instruments and safety-critical controls—to what the crews normally fly. If there are significant differences, the FAA must approve special training programs to safely address them.

Finally, all relevant procedures from the interchange agreement must be incorporated into the certificate holder's operations manuals, ensuring standardized guidance for personnel involved in these operations.

*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.*