Four Corner Concept
The four corner concept begins with a blank slate allowing the design team to start from scratch and build up a system of arrival and departure routes and procedures that are new to the metro area. The idea starts with placing a square over the TRACON airspace as the basic structure. Arriving aircraft enter the TRACON airspace at any of the 4 corners of the square. Arriving aircraft can go to any of the four corners for entry, depending on the current air traffic. This reduces delays further out from the terminal airspace. Once aircraft overfly the corner fix, they can either:
- Go to another corner
- Enter the square and go directly to the intended airport to land
- Enter a large overhead circular pattern to await final sequencing into their destination airport
Controllers will stack aircraft in the circular pattern at different altitudes to accommodate large quantities of aircraft in the metro area. See the diagram below for a conceptual idea of the traffic flows.
By bringing aircraft into the TRACON airspace, controllers can put aircraft into one large containment area directly over the metro airports. Today holding occurs farther from the airports; limiting the number of aircraft controllers can fit into a holding pattern. As these far out holding patterns fill up, it creates more patterns farther out until the whole system backs up to the original airports, grounding flights.
This system can reach all airports and controllers can bring in arriving flights from any direction. This concept will increase the efficiency of air traffic flows into the metro TRACON airspace.
Departing flights will exit the box on any of the sides. This concept allows controllers to utilize Terminal Control Procedures to a far greater extent. These procedures maximize the use of all available airspace in the metro area and will reduce current ‘bottle necks”.
