Definition
The runway, or runways, currently being used at an airport for takeoffs and landings. At a controlled airport, the runway in use is assigned by the tower or other ATC facility. At an uncontrolled airport, pilots select the runway in use based on wind, traffic, and local procedures. The three terms — runway in use, active runway, and duty runway — all refer to the same thing and are used interchangeably.
Plain English
The runway pilots are taking off from and landing on right now. There can be more than one at a busy airport, but only the ones currently in use count.
Context Anchor
You will hear or use this term in airport traffic discussions, tower instructions, airport information broadcasts, and radio calls at airports without a control tower.
Derivation
‘Duty runway’ comes from British and military usage, where a person or thing ‘on duty’ is the one currently assigned to work. The duty runway is the runway on the job at that moment. ‘Active’ has the same idea — the one in action right now, as opposed to the others sitting idle.
Why Pilots Care
Using the correct runway ensures adequate headwind for performance, avoids tailwind or excessive crosswind, and prevents runway incursions or conflicts with other traffic.
Intuition Check
Do not assume “active runway” means there is only one runway involved, or that an aircraft is physically on it at that moment. It means the runway is presently assigned or commonly being used for takeoffs and landings.
Example Sentence 1
The ATIS reported the runway in use as 27, so we planned our pattern entry for a left downwind to that runway.
Example Sentence 2
After checking the ATIS, the pilot requested takeoff on the duty runway and received immediate clearance.