Flight time limitations: Other commercial flying

If you're employed as a pilot by an airline conducting flag operations (generally long-distance international flights), you must count all your commercial flying toward the flight time limits in Part 121. This means if you do any other commercial flying—such as charter flights, cargo operations, or flight instruction for hire—those hours combine with your airline flying hours when calculating whether you've exceeded Part 121's limits.

In practice, this prevents you from maxing out your flight time at your airline job and then taking on additional commercial flying work that would push you beyond safe limits. The regulation ensures that all your commercial flying, regardless of who employs you or what type of operation it is, stays within the cumulative flight time restrictions designed to prevent pilot fatigue. You cannot compartmentalize different commercial flying jobs to work around these safety limits.

*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.*