In accordance with Advisory Circular 150/5325-4A, a crosswind runway should have a length of at least 80 percent of the primary runway length.
In accordance with Advisory Circular 150/5325-4A, parallel runways should have a length based on the airplanes that will use the runways and should also be approximately equal in length.
These runway lengths are based on:
- Individual aircraft performance charts
- The elevation
- Average temperature of the airport
- Runway conditions, and
- Operating weight and engine type of the aircraft
- Environmental noise
- Topographical (except for runway gradient), physical, land use, political, and economic factors.
When aircraft operate during periods of high temperatures, the relative increased density altitude decreases an aircraft’s operational performance. Loss in performance requires longer takeoff distances and faster ground speeds during landings, which results in longer runway length requirements.