Definition
An ATC procedure used to request that a pilot adjust aircraft speed to a specific value, or to a value within a specified range, for the purpose of providing required spacing between aircraft.
Plain English
Air traffic control asks you to fly at a specific speed, or within a specific speed range, so they can keep the right distance between you and other aircraft.
Context Anchor
Commonly heard on the radio during departure, arrival, approach, and other traffic sequencing.
Why Pilots Care
Following the instruction keeps aircraft properly separated and prevents both mid-air conflicts and the need for last-minute go-arounds.
Intuition Check
A speed adjustment is not just a casual change in speed. In ATC use, it is a traffic-management instruction or request, and the pilot should comply unless unable or unsafe.
Example Sentence 1
Approach control issued a speed adjustment of 210 knots to maintain spacing behind the traffic ahead.
Example Sentence 2
We received a speed adjustment of 180 knots so the tower could sequence us between two departures.