Determining the Circle-to-land Radius

September, 28, 2020 by

The size of the protected airspace while circling to land is determined by a standard radius from the ends of the runways. The radius can be found based on the aircraft’s speed and altitude.

There are five speed categories:

Category A: up to 90 knots
Category B: 91 to 120 knots
Category C: 121 to 140 knots
Category D: 141 to 165 knots
Category E: 166 knots or greater

The category can be plugged into this chart to find the radius:

New Circling Area Radii

The pilot should extend their radius from the end of each runway to find the protected airspace, as shown here.

References: Wikipedia,, CFI Notebook

Luca Caviness is an editor for the IFATC Education Group and an IFATC Supervisor. He is also a real-world student pilot.