A ‘one in 15 million’ computer failure in Britain’s air traffic control system was to blame for the Bank Holiday meltdown in UK flight operations.
A software update is due to take place this week to prevent a repeat of the mayhem, it has emerged.
The system failure at National Air Traffic Services (NATS) saw the cancellation of more than 2,000 flights and disrupted the travel plans of more than 300,000 people.
Families were stranded across the world with many forced to sleep on airport floors and facing massive bills, running to thousands of pounds, to find accommodation and alternative routes home.
At the time of the crisis, two sets of NATS computer engineers, one on-site at the Swanwick Air Traffic Control Centre, Hampshire, and a second team working remotely were unable to fix the problem.
A ‘one in 15 million’ computer failure in Britain’s air traffic control system was to blame for the Bank Holiday meltdown in UK flight operations. Pictured: Passengers waiting at Stansted Airport on August 29 after flights were delayed
A software update is due to take place this week to prevent a repeat of the mayhem, it has emerged. The system failure at National Air Traffic Services saw the cancellation of more than 2,000 flights and disrupted the travel plans of more than 300,000 people. Pictured: Travellers whose flights were cancelled/delayed at Stansted Airport last month
It was only resolved after a technical design team and the manufacturer of the computer system were contacted.
NATS chief executive Martin Rolfe, who took home £1.3million this year, said one of its systems failed after it ‘didn’t process (a) flight plan properly’.
He added it was a ‘one in 15 million’ event that caused hundreds of thousands of people to be stranded abroad, some for up to a week.
The subsequent switch to manual processing meant the average number of plans it could handle dropped from around 400 per hour to as few as 60, leading to restrictions on flights to and from UK airports.
More than a quarter of flights were cancelled that day, affecting around 250,000 people.
Cancellations continued for two more days as planes and crews were out of position.
Asked what the odds of this happening were, Mr Rolfe replied: ‘We know it’s at least one in 15 million, because we’ve had 15 million flight plans through this system and we can be absolutely certain that we’ve never seen this set of circumstances before.’
In a preliminary report shared with Transport Secretary Mark Harper, NATS did not identify the route of the flight plan which led to the chaos but stated the aircraft was scheduled to enter UK airspace during an 11-hour journey.
Airlines’ flight plans feature waypoints, which represent locations and are identified by a combination of letters and numbers.
The flight plan which caused last week’s disruption was submitted to Eurocontrol – which oversees ATC across Europe – before being passed on to NATS.
The process led to the plan featuring two waypoints around 4,000 nautical miles apart but with identical names.
This meant Nats’ software was unable to extract a valid UK portion of the flight plan and reacted by shutting down.
A back-up system followed the same steps and also stopped working.
Nats said an ‘operating instruction’ has been put in place to allow the ‘prompt recovery’ of the system if there is a repeat of these circumstances. A ‘permanent software change’ to prevent it shutting down in such an event is expected to be implemented in the coming days.
Mr Rolfe said: ‘I’m very confident that the changes we’re making here will prevent this incident from happening ever again.’
The CAA is today triggering an independent inquiry – expected to take three months – into what it has called ‘an improbable data anomaly’.
An initial investigation by NATS points to a software glitch linked to the flight plan of a single long-haul flight passing through UK airspace.
The flight was due to take off 4am on Bank Holiday Monday and then fly over the UK before going on to land at its destination at 3pm on the same day.
A problem identifying the entry and exit points through UK airspace meant both the main computer system and its back-up went into ‘critical exemption’ mode and effectively stopped working ‘to preserve safety’.
As a result, air traffic controllers were reduced to manually plotting the comings and goings of aircraft, which dramatically reduced the number of flights that could be handled.
The former BA boss and head the international airlines body, IATA, Willie Walsh, has estimated the cost of cleaning up the mess for carriers, including paying refunds and covering the expenses of passengers, could be as much as £100 million.
He has called for a change in the compensation regime to make NATS responsible for any losses caused by its failures.
The details of the airline and flight plan linked to the computer failure have not been revealed, however there are indications it was a transatlantic flight between North America and France.
CAA sources say the details of the flight are not relevant as ‘a correct flight plan was entered’ and this was entirely a ‘downstream systems issue’.
The NATS investigation states that this was the first time the problem had occurred in the five years the computer system has been operating, handling more than 15 million flights. One person close to the inquiry suggested that this was a ‘one in 15m’ event. Pictured: Disrupted travellers at Stansted Airport on August 29
The NATS investigation states that this was the first time the problem had occurred in the five years the computer system has been operating, handling more than 15 million flights. One person close to the inquiry suggested that, as a result, this was a ‘one in 15m’ event.
NATS said an imminent change to the system software should prevent any repeat.
It said: ‘A permanent software change by the manufacturer… will prevent the critical exception from recurring for any flight plan that triggers the conditions that led to the incident.’ On the issue of whether NATS should pay up for the disruption, it said: ‘It is not within NATS’ remit to address any wider questions arising from the incident such as cost reimbursement and compensation for the associated disruption.’ There is no evidence of any cyber and the CAA is satisfied there was no risk to the safety of travellers.
It said: ‘This technical event is now understood and should it reoccur would be fixed quickly with no effect to the aviation system.
‘A software adaptation is planned to be implemented by the manufacturer this week once testing is complete and change process assessed, this will mean it will not reoccur.’
Source: | This article originally belongs to Dailymail.co.uk