Flight engineer

This regulation determines when Part 121 air carriers must have a flight engineer as part of the flight crew.

For older aircraft with type certificates issued before January 2, 1964, a flight engineer is required if the airplane's maximum certificated takeoff weight exceeds 80,000 pounds. This affects legacy aircraft like early Boeing 707s and Douglas DC-8s that were designed with flight engineer stations.

For newer aircraft type certificated after January 1, 1964, whether a flight engineer is required depends on the aircraft's type certification under § 25.1523. Modern aircraft are typically certificated for two-pilot operation without a flight engineer, as improved automation and cockpit design eliminated the need for this crew position.

In practice, this regulation primarily affects operators of vintage heavy aircraft, as most modern Part 121 airplanes are certificated for two-crew operation.

*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.*