Fuel supply: Turbine-engine powered airplanes, other than turbo propeller: Flag and supplemental operations

This regulation sets fuel requirements for turbine-engine jets (not turboprops) operating under Part 121 flag and supplemental rules.

For operations within the lower 48 states and DC, flag operators may use the domestic fuel rules (§121.639), and supplemental operators use §121.643.

For international operations (outside the lower 48 and DC), jets must carry enough fuel to:

• Reach the destination airport
• Fly an additional 10% of the total flight time
• Reach the farthest alternate airport (if required)
• Hold for 30 minutes at 1,500 feet above the alternate (or destination if no alternate required)

If no alternate airport is required for the destination, the aircraft must carry enough fuel to reach the destination plus two hours at normal cruise consumption.

The FAA may require additional fuel for specific routes when safety demands it.

*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.*