Flights to Heathrow and Gatwick airport could be delayed over the next three weeks as air traffic controllers update the technology that they use.
The National Air Traffic Services (Nats) are switching between paper flight information strips and a new digital system at their control centre in Swanwick, Hampshire.
The affected airspace includes the approach for Heathrow and Gatwick as well as flight paths to Luton, Stansted and London City.
As the new system is introduced, and controllers adjust to using it, the number of flights allowed to land at London’s two main air travel hubs will be strategically reduced.
For the next ten days, arrivals at Heathrow will be limited to 80% of maximum capacity, and average delays of 20 minutes are expected.
Arrivals will then operate at 90% of capacity for the following ten days before returning to normal levels.
The need to land planes slightly earlier or later normal will also mean there is increased noise pollution for those living under flight paths at night.
However, Nats has said that it expects delays to be minimal, and asks passengers not to change travel plans or the time they arrive at the affected airports.
The move to a new digital system to manage traffic at Britain’s main airports is part of a £700 million programme designed to cater for increasing amounts of air travel.
The news of planned disruption at Heathrow and Gatwick comes at the same time as a shock announcement that a system failure will temporarily reduce the capacity of flights across the European network by 10%.
Eurocontrol, the air navigation safety body for Europe, issued a statement this afternoon saying that the Enhanced Tactical Flow Management System had experienced an unexpected failure.
A statement from Eurocontrol said:
Today 29,500 flights were expected in the European network. Approximately half of those could have some delay as a result of the system outage.
The system regulates the flow of flights around Europe and arranges slots for aeroplanes taking off and landing.
Eurocontrol said that contingency measures have been put in place, and that air traffic control and air safety have not been compromised.