Definition
The pilot's best estimate of the clock time at which a flight will depart, normally expressed in Coordinated Universal Time (UTC, also called Zulu) on flight plans and weather briefings.
Plain English
The time you expect to take off. It's a planning estimate, not a guaranteed time, and it's usually written in Zulu time on flight plans.
Context Anchor
Seen when requesting a weather briefing, filing a flight plan, or giving basic flight information before departure.
Why Pilots Care
It allows pilots and ATC to coordinate timing, fuel, and current weather information for a safe departure.
Intuition Check
Do not read “estimated” as exact. ETD is your best planned departure time, not a guaranteed takeoff time.
Example Sentence 1
She filed the flight plan with an ETD of 1430 Zulu and called for a standard weather briefing thirty minutes before that.
Example Sentence 2
Weather delayed the ETD by thirty minutes while the pilot waited for updated conditions.