London's Heathrow airport has started a four-month trial of new mixed-mode operations today (1 November), allowing it to temporarily use both runways for departures or arrivals.
The trial was one of a number of recommendations made by the coalition government's South East Airports Task Force in July, and comes as the main political opposition, the Labour party, abandoned support for a third Heathrow runway - a position already adopted by the government.
Heathrow normally uses one runway for departures and the other for arrivals. Implementation of the new freedom is conditional on certain triggers agreed with the Department for Transport and the Civil Aviation Authority.
If a flight is anticipated to be delayed on arrival or departure by at least 10min, for example, or the headwind component on approach is greater than 20kt (37km/h) at 3,000ft (915m) then the new procedure can apply.
It can also be applied if the arrival or departure flight schedule is anticipated to run later than 30min, if 30% of flights are running outside of the airport's 15min punctuality target, or if the airport needs a period of time to recover from disruption such as snow.
Once operations are running within normal parameters, the trial procedure would be de-activated. Heathrow operator BAA said the trial - due to run until 29 February 2012 - will help it cut delays and reduce the number of night flights. "It's about making Heathrow better not bigger," it said.
Alongside the trial of dual arrivals and dual departures operations, the airport will also test a number of other measures, including landing an Airbus A380 on the runway closest to its stand, reducing the effects of the aircraft's wake vortex on other traffic.
It will also test landing small aircraft on the designated departures runway and using the southern runway for departures and arrivals from Terminal 4, cutting the taxi distance for aircraft. These tests will take place in two four-week periods, 28 November-25 December and 16 January-12 February. A second phase of the main trial will run from 1 July to 30 September.