Definition
An air traffic control arrival and departure design used at busy airports in which arrival and departure routes are separated into four distinct corridors positioned at the four corners of the terminal area. Arrivals are funneled through two opposing corner posts, while departures are channeled through the other two, allowing simultaneous high-volume traffic flow without route conflicts.
Plain English
A way of organizing the airspace around a busy airport so that aircraft arriving and aircraft leaving use four separate gateways at the corners of the airport area, instead of crossing each other's paths.
Context Anchor
Seen in hot-air balloon equipment descriptions, preflight inspection discussions, and basket design references.
Derivation
The name comes from the geometric layout: four 'posts' or fixed gateways set at the corners of the airport's terminal airspace, like the four corner posts of a fence marking the entry and exit points.
Why Pilots Care
It raises hourly arrival capacity and reduces delays by keeping multiple approach paths independent.
Analogy
Picture a small canopy held up by four poles, one at each corner. In this balloon arrangement, the posts serve a similar purpose for the burner frame above the basket.
Intuition Check
Post does not mean “after” here. It means an upright support, like a pole, located at a corner of the basket.
Example Sentence 1
Atlanta's terminal airspace uses a four-corner post configuration, so arrivals from the west are funneled through a fixed gateway northwest of the field.
Example Sentence 2
Pilots on the north arrival were sequenced behind traffic using the east post in the four-corner post configuration.