Definition
Spacing between aircraft, levels, or tracks established and maintained by air traffic control to keep aircraft a safe distance apart.
Plain English
Keeping aircraft far enough apart from each other — sideways, lengthways, or by altitude — so there is no risk of collision. ATC arranges this spacing.
Context Anchor
Seen in air traffic control procedures, especially in international operations and controlled airspace discussions.
Derivation
From the Latin separare, meaning 'to set apart.' In ATC use, it keeps the everyday sense — keeping things apart — but applied specifically to aircraft positions in three dimensions.
Why Pilots Care
Maintaining proper separation is essential to avoid mid-air collisions and is enforced by air traffic control.
Intuition Check
Do not read separation as just any distance between two things. In this context, it means enough approved spacing to keep aircraft safely apart.
Example Sentence 1
ATC turned the inbound traffic 20 degrees right to maintain separation from the departing jet.
Example Sentence 2
The flight maintained 1,000 feet of vertical separation while climbing through the airway.