Definition 1 of 2
Definition
The time an aircraft is expected to depart, as filed by the pilot on an IFR flight plan. For airports with a clearance delivery procedure, the proposed departure time is the time the pilot expects to be ready for taxi. For airports without clearance delivery, it is the time at which the flight plan becomes active and clearance can be issued.
Plain English
The takeoff time the pilot writes on their flight plan. It tells ATC roughly when to expect the flight to get going so they can have a clearance ready.
Context Anchor
Seen when filing or updating flight plan information and when coordinating expected departure timing with ATC or flight operations.
Derivation
“Proposed” comes from a Latin-rooted word meaning “put forward.” That helps here because the time is being put forward as the expected departure time, not treated as a guaranteed or already-approved time.
Why Pilots Care
ATC relies on this time to sequence departures, manage traffic flow, and decide when to issue or hold a clearance.
Intuition Check
“Proposed” does not mean approved or guaranteed; it means expected or planned. “Departure time” here means when the aircraft is expected to become airborne, not when it starts taxiing or leaves the ramp.
Example Sentence 1
He filed an IFR flight plan with a proposed departure time of 1400Z so the clearance would be ready when he called ground.
Example Sentence 2
Clearance delivery asked whether the proposed departure time was still accurate before issuing the clearance.