Definition
A runway whose magnetic heading, when aligned for takeoff or landing, is approximately 330 degrees. Runways are numbered using the first two digits of their magnetic alignment rounded to the nearest ten, so Runway 33 points roughly toward 330° on the compass (slightly west of due north).
Plain English
A runway you line up on while pointing about 330 degrees on the compass — that is, mostly north with a bit of west.
Context Anchor
Seen on airport signs, airport diagrams, radio calls, and in takeoff or landing instructions.
Derivation
The number is simply the runway's magnetic heading divided by ten and rounded. A heading of 330° becomes '33'. The trailing zero is dropped to keep the painted number short and readable from the air.
Why Pilots Care
Knowing the runway number allows pilots to select the correct runway aligned with the wind and navigate properly during takeoff and landing.
Intuition Check
Do not read “Runway 33” as a runway count or a gate number. In aviation, the number tells you the runway’s compass direction.
Example Sentence 1
The tower cleared us to land on Runway 33, so we turned to a heading of about 330 degrees on final.
Example Sentence 2
ATC cleared the aircraft to land on Runway 33 at the airport.