Airplane limitations: Type of route

This regulation sets distance limits from suitable airports for Part 121 airline operations based on aircraft type and engine configuration.

Turbine-powered aircraft must stay within specific flying times (at one-engine-inoperative cruise speed) from an adequate airport: 60 minutes for two-engine planes, or 180 minutes for passenger aircraft with more than two engines. Operations beyond these limits require special approval through ETOPS procedures (Appendix P) and must be authorized in the carrier's operations specifications. These aircraft also cannot operate in North or South Polar Areas without approval.

Reciprocating-engine aircraft are limited to 60 minutes from an adequate airport unless the Administrator grants an exception based on terrain, operation type, or aircraft performance.

Extended overwater operations in land airplanes require the aircraft be certificated for ditching, with specific exceptions for certain older aircraft types like the DC-3 and several others listed in the regulation.

*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.*