WHY WAS LONDON AIRSPACE CLOSED FOR HOURS

[Anthea]

BBC News UK

Flights disrupted after computer failure at UK control centre

WHY WAS LONDON AIRSPACE CLOSED FOR HOURS

Certainly NOT because of computer problems

Passengers are facing widespread flight disruption after a computer failure at the UK's air traffic control centre.

Nats said it was in the process of returning to normal operations after a "technical problem" at its Swanwick control centre caused delays and grounded some flights.

Problems were reported around the UK.

The government said the scale of the disruption was "unacceptable" and said it had asked for a "full explanation" of what had gone wrong.

This included delays at Heathrow and Gatwick, where departing flights were grounded for a time. Other UK airports reported knock-on effects.

It comes a year after a telephone glitch at the Hampshire control room caused huge disruption - one of a number of technical hitches to hit the part-privatised Nation Air Traffic Services since the centre opened in 2002.

Reported problems around the country include:

Heathrow: Fifty flights cancelled. Others delayed but planes now landing and taking off
Gatwick: Flights are now departing but still subject to delays
Stansted: Flights still landing, no flights departing
London City: Cancellations and delays
Luton: All flights experiencing delays
Bristol: Limited departures reported
Luton: All flights experiencing delays but planes now leaving
Edinburgh: No queues but passengers being advised to check with their airlines
Glasgow: Some delays to departures
Southampton: Experiencing ''problems''
Oxford: Experiencing "some delays", mainly to services arriving from overseas
Leeds Bradford: All flights out and most flights in suspended until 1900
Birmingham: Some departures are being re-routed to avoid flying through London airspace
East Midlands: Departures and arrivals delayed but passengers advised to turn up as normal

One source told the BBC the problem was caused by a computer glitch that co-ordinates the flights coming into London and puts the flights in sequence as they come into land or take off.

He described it as a "flight planning tool problem".

Travel body Abta encouraged passengers expecting to take a flight to contact their airline.

Vicky Lane, a passenger on a grounded London to Dublin plane at Gatwick said: "We've been stuck on a Ryanair flight... for over an hour.

"The doors are open and we're really cold. I'm not sure when we will be leaving."

Another passenger, on a flight to Paris, said his plane had "circled around the Lake District for half an hour before turning back to Edinburgh".

Ed Bott told the BBC he was: "Currently sitting on the tarmac. None the wiser. Waiting for news as to what's happening."

Swanwick controls the 200,000 square miles of airspace above England and Wales, cost £623m to build, and employs about 1,300 controllers.

But the facility, which handles 5,000 flights every 24 hours, has had a troubled history.

It opened in 2002, six years after its planned commissioning date - a delay which National Air Traffic Services (Nats) said was due to problems with the software used to power its systems.

Almost a year after it opened, a senior air traffic controller raised concerns with the BBC about health and safety standards and complications with radio communications - which he said cut out erratically.

Technical problems and computer faults hit flights in 2008 and again last summer. And, in December 2013, problems with the internal telephone system then caused further delays.

Aviation journalist David Learmount said the IT problem would cause "major disruption" but would be resolved by Saturday.

"This impacts not just people within the UK, it impacts flights heading here from anywhere - anything heading this way will be told some of them can't be accepted, and they will have to go back to where they flew from or consider diverting to other countries," he told the BBC.

The RAF - which has its own air traffic control systems - said the UK military was unaffected.

By Ben Ando, BBC News

As soon as air traffic control has a problem, nothing is allowed to take off that might add to the problem.

This is unlikely to be power problem as there are duplicate and back-up systems - including even diesel generators at a push.

It is more likely to be software, which caused the last major problem when the incoming morning crew could not switch over from night-time control system.

With aircraft out of position, or flight crews out of hours, there are likely to be knock-on problems for many flights.

http://www.bbc.co.uk/news/uk-30454240

Anthea: The different air traffic control systems are NOT interconnected

At any given time there are 100s of planes in the air in and around London

The air traffic control system is specifically designed to run in independent sections so that should one section have problems another section could take over

Were it not designed in such a way it would put all the air traffic and souls in extreme danger

Also if the entire system had closed down - planes would have been falling out of the sky all over the place

WHY WAS LONDON AIRSPACE CLOSED FOR HOURS