FLIGHT problems across the south on Friday were caused by an unprecedented systems failure.
Airports were forced to delay and cancel flights after a technical problem occurred at Swanwick-based National Air Traffic Services (Nats).
The problems started Friday afternoon and affected Heathrow, Gatwick, Southampton and other airports across the country.
The company revealed that the problem happened when one of their computer systems failed while switching between on and off.
A statement said: ‘In normal operations the number of workstations in use versus in standby fluctuates with the demands of the traffic being controlled.
‘In this instance a transition between the two states caused a failure in the system which has not been seen before.
‘The failure meant that the controllers were unable to access all of the data regarding individual flight plans which significantly increases their workload.
‘Our priority is to maintain a safe operation for the flying public; consequently when the failure occurred we immediately took steps to reduce the traffic into and out of the UK network.’
Over the weekend, Heathrow had 38 flights cancelled before 9.30am yesterday and many flights Friday evening were delayed for several hours.
Chief executive of Nats, Richard Deakin, said: ‘The air traffic control systems used by Nats are robust and have contingency built in to them so that if a problem occurs, it can be identified quickly and resolved.
‘Our contingency plans worked as they should have done on Friday and allowed our complex systems to be fully back up and running after 45 minutes.
‘Failures like this are extremely rare, but when they occur it is because they are unique and have not been seen before.
‘If they do occur, root causes are identified and corrections made to prevent them happening again.’