Definition 1 of 2
Definition
A coordination procedure in which a tower or other air traffic control facility is required to contact the appropriate center or approach control before releasing a departing IFR aircraft into controlled airspace. The release issued by the controlling facility specifies the time window or conditions under which the aircraft may depart.
Plain English
Before letting an IFR flight take off, the local tower must phone the controlling facility and get permission. The aircraft can only leave the ground during the time slot that facility approves.
Context Anchor
Used in air traffic control coordination for departures, especially when traffic flow, spacing, or route restrictions require Center approval before takeoff.
Derivation
“Call” means to make contact, and “release” means to let something go from control or restraint. In this aviation use, the aircraft is not released by the departure controller until the next control facility has accepted it into the traffic flow.
Why Pilots Care
Prevents frequency congestion by letting the pilot initiate contact only when actually ready, ensuring the clearance is timely and current.
Intuition Check
Do not read this as the pilot personally calling to be released. It means one air traffic control facility must contact another facility and get approval before the aircraft is allowed to depart.
Example Sentence 1
Tower advised the pilot of a short delay because the departure was a Call for Release and they were still coordinating with center.
Example Sentence 2
After completing the run-up, the pilot called for release and received the IFR clearance directly from approach control.