Definition
The order in which air traffic control releases departing aircraft from an airport, taking into account aircraft type, requested route, wake turbulence separation, traffic flow, and any flow control restrictions imposed by ATC.
Plain English
The lineup ATC builds for which aircraft takes off first, second, third, and so on. It is not always the order pilots arrived at the runway.
Context Anchor
Used at towered airports before takeoff, especially while aircraft are waiting near the runway for instructions from the tower.
Derivation
Departure comes from an older word meaning to go away or leave. Sequence comes from a Latin word meaning to follow. Together, the phrase means the order in which aircraft follow one another as they leave the airport.
Why Pilots Care
Determines your position in the takeoff lineup and affects how long you wait before receiving a clearance.
Intuition Check
Departure sequence does not mean the route you will fly after takeoff. It means the order ATC is using for aircraft waiting to take off.
Example Sentence 1
Tower advised, 'Cessna 7321X, you are number three in the departure sequence behind the Citation and the King Air.'
Example Sentence 2
With heavy traffic, the controller adjusted the departure sequence to prioritize IFR aircraft.