Definition
A flight crewmember assigned to flight duty for the purpose of relieving another flight crewmember from duty at an onboard rest facility during the cruise portion of a flight. Reserve flight crewmembers are used on long-haul operations to allow primary crewmembers scheduled in-flight rest while the aircraft remains under the control of fully qualified pilots.
Plain English
An extra qualified pilot carried on long flights so that one of the regular pilots can leave the controls and rest while the extra pilot takes their seat.
Context Anchor
Seen in airline, commuter, and charter scheduling, especially in duty-time, rest, and crew assignment rules.
Derivation
Reserve' comes from the Latin 'reservare,' meaning 'to keep back' or 'to hold in store.' The reserve crewmember is held back from primary duty and brought into the seat when needed, exactly matching the original sense of the word.
Why Pilots Care
Understanding reserve status affects how pilots plan rest, duty times, and availability for unexpected flights.
Analogy
Similar to an on-call doctor who waits to be summoned if a regular staff member cannot work.
Intuition Check
Reserve does not mean the crewmember is off duty or free for personal use. In this context, it means the crewmember is being held available for a possible flight assignment.
Example Sentence 1
The 14-hour flight to Tokyo was scheduled with two reserve flight crewmembers so the captain and first officer could each take a rest break in cruise.
Example Sentence 2
As a reserve flight crewmember, she had to stay within a certain distance from the airport in case she was needed.