Weather can significantly affect aircraft operations. Low cloud, fog and rain may impede visibility at or around an airport while thunderstorms and lightning can cause serious disruption to flight schedules.
Thunderstorms, and the rapidly rising or falling air currents which usually accompany them, can make air travel uncomfortable for passengers and difficult for pilots in control of aircraft. Aircraft are unable to take-off or land during a storm and will often be re-routed around storm cells or diverted from their destinations. Thunderstorms and lightning strikes near airports may also stop ground operations until they pass.
Airservices National Operations Centre in Canberra works closely with the Bureau of Meteorology (BoM) and air traffic controllers nationally to minimise disruptions caused by weather. Air traffic controllers will adjust the number of aircraft movements per hour to match the operating conditions at each airport.
Airservices does not have the authority or ability to close an airport. Airport operators are the only authority able to close an airport and this decision would only be taken in extreme circumstances. For example, the Queensland floods in 2011 closed Rockhampton Airport for several weeks.
Impact on runway selection
Weather, particularly wind speed and direction, is generally the major factor to determine which runways to use at an airport, in which direction aircraft will take off and land and which flight paths are used.
Aircraft must take off and land into the wind or with minimal tail wind. This means current and forecast wind direction dictates the selection of runway/s in use at any time. Wind direction can change with short notice and this may affect the flight paths and runways used.
Wind blowing across the runway is called a cross wind. Generally, aircraft can take off or land where there is only a low cross wind, usually up to a speed of about 15 knots (28 km/h). Cross winds above that speed may force aircraft to use another runway or divert to an alternative airport.
More information on runway selection.
Windshear is a sudden change in wind direction or speed and is usually associated with thunderstorm activity. Windshear can be either vertical or horizontal and can have a significant impact on the control of aircraft during take-off and landing.
A condensation trail, or contrail, is a thin trail of condensed water vapour sometimes seen trailing behind aircraft flying at high altitudes. Due to their unusual behaviour, they can sometimes be mistaken for a UFO.
Airservices works closely with the BoM’s Darwin-based Volcanic Ash Advisory Centre (VAAC) to monitor volcanic ash in the Asia-Pacific region.
Airservices cannot close or restrict airspace as a result of volcanic ash but provides advice to airlines on the likelihood of encountering ash. Airlines make individual decisions on whether or not to fly in, or around, ash-affected airspace or to suspend operations.