Plain English Meaning
Slices of upper-level airspace that ATC divides up so each controller can manage the high-flying jet traffic in their assigned area.
Full Definition
Air traffic control sectors that handle aircraft operating at or above flight level 240 (24,000 feet MSL), typically used by jets and turboprops on long-distance, high-altitude routes. Each sector is a defined block of airspace assigned to a specific controller responsible for traffic within it.
Context Anchor
Seen in discussions of en route instrument flying and how ATC divides airspace among controllers.
Derivation
Sector comes from a Latin word meaning “cutter” or “section.” That helps here because a sector is a cut-out section of airspace, not just a general area.
Why Pilots Care
Determines which frequency to monitor and which controller to expect handoffs from during high-altitude cruise.
Intuition Check
Do not read “sector” as just a wedge-shaped slice on a chart. In this context, it means a defined three-dimensional block of controlled airspace assigned to a controller.
Example Sentence 1
After climbing through FL240, the controller handed us off to the high altitude sector for the en route portion of the flight.
Example Sentence 2
Clearance for direct routing required coordination across three high altitude sectors.