Airplanes: Reciprocating engine-powered: Weight limitations

This regulation sets weight limits for Part 121 operations using reciprocating (piston) engine airplanes based on airport elevation.

You cannot take off from an airport whose elevation falls outside the range your airplane's performance data covers for maximum takeoff weights. The same restriction applies to your destination and alternate airports—they must be within the elevation range for which maximum landing weights are determined.

You must not exceed the maximum authorized takeoff weight for your departure airport's elevation, and you must ensure your airplane's weight upon arrival won't exceed the maximum authorized landing weight for the destination's elevation (accounting for normal fuel and oil burn).

These requirements ensure the airplane can perform safely at different elevations where air density affects engine performance and aerodynamic efficiency. The regulation doesn't apply to large nontransport category airplanes operated under the special provisions of §121.173(c).

*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.*