Plain English Meaning

Anyone with an official job to do on the aircraft while it's flying — the pilots and anyone else assigned to operate or serve the flight. Passengers are not crewmembers.

Full Definition

A person assigned to perform duties in an aircraft during flight time. In FAA usage, this includes flight crewmembers (pilots, flight engineers, flight navigators) and other crewmembers such as flight attendants or aircraft loadmasters. A crewmember is on duty for the operation of the aircraft, not simply a passenger riding along.

Context Anchor

Seen in medical certificate rules when deciding whether a person may legally serve in a required role on a flight.

Derivation

From 'crew' (a group assigned to a shared task, originally a ship's working company) and 'member' (one of a group). The aviation use carries over directly from usage, where the crew were the people working the vessel as to being carried.