Wherever possible, aircraft take-off and land into the wind or with minimal tail wind. Runway selection is monitored at all times as weather conditions can quickly change. The decision to use a particular runway has an impact on the amount of aircraft noise that will be experienced by residents around airports.
In many Australian cities, prevailing winds vary by season. This means that one runway may get used more in one season than in another. As a result, some communities may be affected predominantly by noise from arriving aircraft in one season, and by departing aircraft in another.
Other factors that air traffic control take into consideration when deciding which runway to use include:
- the number and type of aircraft programmed for the airport
- length of runway(s)
- weather conditions (both present and forecast); including wind velocity and gradient, wind shear, wake turbulence effects and position of the sun
- availability of approach aids in poor visibility conditions
- location of other aircraft
- taxiing distances, including availability of taxiways
- braking conditions.
Some airports also have ‘preferred runway’ systems. This means that if wind conditions, workload and traffic conditions permit, a particular runway will be used to move traffic as efficiently as possible to reduce the noise impact over residential areas.
Airservices has produced a factsheet on runway selection.