Around Heathrow the wind usually blows from the west. Because aircraft must land into the wind, the majority of aircraft therefore arrive from the east (over London) and take off towards the west (over Berkshire/Surrey). This is known as westerly operations. Westerly operations occur for about 70% of the year.
When the wind blows from the east, the reverse happens. Aircraft arrive from the west (over Berkshire) and depart towards London. This is called easterly operations and we are ‘on easterlies’ for about 30% of the year.
The percentage of westerlies and easterly operations varies from week to week and month to month. It is also affected by our ‘westerly preference’. We provide live updates on the direction Heathrow is operating via our website and twitter feed (follow us @HeathrowNoise).
The direction of operation is determined by air traffic controllers in relation to the wind speed and direction on the airfield at 1,000ft and 2,000ft. The position is constantly kept under review. The weather forecast made by the Met Office is not always a reliable indicator of what is happening at Heathrow since the Met Office forecast for the public relates to ground level.
Due to the direction of operation determined by the wind, the operation can change direction more than once in a day. We therefore are unable to control or predict which direction the airport will be operating in.