Heathrow flights 'back to normal'

British airports were forced to delay and cancel flights

British Airways says flights to and from Heathrow are back to normal after a computer glitch at the UK's main air traffic control centre on Thursday.

Some short-haul flights were cancelled on Friday morning, but by lunchtime BA said everything was back on schedule.

Airports were hit by delays in flights across south-east England airspace.

The problems at the air traffic control centre at Swanwick, Hampshire, interrupted the flow of information to controllers at their work stations.

Other UK airports, including Belfast, Cardiff, Luton and Edinburgh reported flights were back to normal on Friday morning.

'Fully operational'

A BA spokesman said the further cancellations at Heathrow were the result of a knock-on effect of 35 cancelled domestic and European flights on Thursday.

But he said the last cancellation was mid-morning and the airline was trying wherever possible to re-book flights for passengers affected.

A Heathrow spokeswoman said it was only BA flights that had been affected.

LONDON AIR TRAFFIC CONTROL The London air traffic control centre at Swanwick, Hampshire, has two parts with different responsibilities: The London Area Control Centre (LACC) is responsible for aircraft flying over England and Wales The London Terminal Control Centre (LTCC) handles aircraft approaching and departing south-east England airports Both centres are run by National Air Traffic Services (Nats), which is part-owned by the government and a consortium of airlines Why Swanwick hit the headlines Swanwick's troubled history

A spokesman for National Air Traffic Services (Nats), which runs the air traffic control centre at Swanwick, told BBC News: "It was restored by 1900 BST last night and we've been fully operational since then."

He said that due to the fault that blocked the flow of information to controllers at their work stations, the controllers had operated manual systems at reduced capacity.

An investigation was being carried out, he added.

Passengers at airports across the UK, including Heathrow, Cardiff, Belfast and Glasgow, had faced delays.

But by early Friday morning, Luton, Cardiff and Belfast airports all said their services had returned to normal.

A BAA spokeswoman for Aberdeen, Edinburgh and Glasgow airports said services were back to normal, save for "minimal" delays of 10 to 15 minutes.

'Reduced capacity'

On Thursday National Air Traffic Services (Nats) said engineers were called in to investigate the cause of the computer fault at the London Area Control Centre, which deals with planes flying over south-east England.

The London Terminal Control Centre, also based in Swanwick, which is responsible for landing and departing aircraft, continued to operate fully but it had been restricting departures due to the additional workload.

Nats said restrictions on take-offs and landings were introduced to ensure passenger safety while controllers operated manual systems at reduced capacity.

BBC transport correspondent Tom Symonds said the problems stemmed from a glitch with computers which deal with information about flights when they are at higher altitude.

Air traffic controllers could still see where planes were, but were finding it difficult to identify them, he said.

This resulted in a reduced flow of aircraft from airports, with planes at Heathrow leaving every two minutes rather than every 90 seconds.

Airport authorities have advised passengers to contact their airlines before travelling.