Definition
A defined volume of airspace centered above the runway and the runway approach and departure surfaces, kept clear of taxiing, holding, or parked aircraft and of fixed obstacles (other than frangible navigational aids) during arrival and departure operations. The OFZ protects aircraft from collision hazards in the critical phases close to the runway.
Plain English
An invisible protected box of air around the runway that must be kept clear of aircraft and obstacles during takeoffs and landings, so arriving and departing planes have a safe, unobstructed path near the ground.
Context Anchor
Seen in airport design, runway safety, approach procedures, and air traffic control discussions about keeping the runway environment clear.
Derivation
From 'obstacle' (Latin obstaculum, something standing in the way), 'free' (clear of), and 'zone' (a defined area). The name describes exactly what the airspace is: a defined area kept clear of obstacles.
Why Pilots Care
Ensures pilots understand the protected airspace needed for safe operations on precision approaches and departures.
Intuition Check
Obstacle Free Zone does not mean the entire airport area is clear. It refers to a specific, defined volume of air immediately around and above the runway and its approach and departure paths.
Example Sentence 1
Ground hold the Cessna short of the taxiway intersection until the arrival has cleared, so the OFZ remains protected.
Example Sentence 2
Approach charts specify the OFZ dimensions to confirm obstacle clearance on the ILS.