Definition
An air traffic control instruction issued to a pilot conducting an instrument approach when landing must be made on a runway other than the one aligned with the approach being flown. After completing the instrument approach, the pilot maneuvers the aircraft visually around the airport at low altitude to align with the assigned landing runway. ATC issues the instruction in the form 'Circle to runway (number)' when the circling maneuver is not at the pilot's discretion or when the controller wishes to specify the landing runway.
Plain English
After flying the instrument approach, fly a visual loop around the airport and land on the runway the controller named, not the one the approach pointed at.
Context Anchor
Heard in IFR approach clearances when the approach being flown does not line up with the runway that will be used for landing.
Derivation
The word 'circle' here refers to the visual maneuver flown around the airport at low altitude to position for a different runway. It is not a literal circle but a curved path — base leg, downwind, or a wider loop — flown by sight after breaking out of the clouds.
Why Pilots Care
Allows landing when the straight-in runway is unsuitable due to wind, obstacles, or runway length, while still requiring visual contact with the airport throughout the maneuver.
Grounding Statement
The key idea is: fly the approach first, then use visual maneuvering to get to the assigned landing runway.
Intuition Check
Circle does not mean fly a complete circle around the airport. Here it means visually maneuver near the airport after the approach so you can land on the runway ATC specifies.
Example Sentence 1
Tower instructed the pilot, 'Cleared ILS Runway 27 approach, circle to Runway 18.'
Example Sentence 2
Due to a strong crosswind, the flight was cleared to circle to runway 18 instead of landing straight in.