Airplanes: Reciprocating engine-powered: En route limitations: All engines operating

This regulation sets minimum climb performance requirements for reciprocating engine-powered airplanes operating under Part 121, with all engines running normally.

The airplane must be able to climb at a rate of at least 6.90 times its stall speed (VSo) in knots, expressed as feet per minute. This climb rate must be achievable at 1,000 feet above the highest terrain or obstruction within 10 miles either side of the planned route, accounting for normal fuel and oil consumption during flight.

For example, if an airplane's VSo is 60 knots, it must maintain at least a 414 feet-per-minute climb rate (60 × 6.90) at the specified altitude.

This ensures the aircraft has adequate performance margins for safe en route operations over varying terrain. The rule doesn't apply to certain older certificated airplanes under Part 4a of the Civil Air Regulations or large nontransport category airplanes operated under specific 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.*