The chaos that grounded flights in the UK on Bank Holiday Monday was caused by a technical issue involving incoming flight data, it has been confirmed by air traffic control bosses.

Thousands of passengers were left stranded abroad due to cancellations and needing to either seek alternative routes home, or in many cases sleep in airport lounges.

The situation, led to a knock-on effect with on-going disruption which means many travellers are still stuck and unsure of exactly when they will be able to get themselves back.

The National Air Traffic Services (NATS) had already said there were no signs that the failure was caused by a cyber-attack.

The incident will be investigated by the Civil Aviation Authority (CAA).

Systems unable to deal with data

NATS say a flight plan which its systems could not process was the reason for all the problems. The Chief Executive Martin Rolfe explained that a particular piece of flight data received by its systems was behind the issue: “Our systems, both primary and the back-ups, didn’t handle the data and responded by suspending automatic processing to ensure that no incorrect safety-related information could be presented to an air traffic controller, or impact the rest of the air traffic system.”

He added that this was “incredibly rare” and he was confident it would not arise again as procedures had immediately been put in place to make sure if it were to occur ever again it would be resolved very quickly.

French connection?

There is a suggestion, which Mr Rolfe said he would not want to speculate upon, which seemed to point the finger towards a flight plan submitted by a French airline as being behind the problem.

He did confirm however, that NATS was working with the CCA to provide a preliminary report to the transport secretary, Mark Harper, and that the report’s conclusion would be made public.

Night flights to help backlog

In an effort to alleviate the growing backlog of flights, the Department of Transport has said it has approved night flying to all the UK airports that it regulates, hoping to end the misery being suffered by those holidaymakers and travellers still stranded and desperate to return home.

Airlines to suffer

Willie Walsh, who is the head of the International Air Transport Association, called the failure “unacceptable” and said he felt for passengers who continue to suffer “huge inconvenience” and airline staff put under “considerable additional stress”.

He added that airlines would “bear significant sums in care and assistance charges” on top of the costs of disruption to crew and aircraft schedules.

Hundreds of cancellations

Analysis of flight data websites showed at least 281 flights – including departures and arrivals – were cancelled on Tuesday 29 August, at the UK’s six busiest airports, consisting of 75 at Gatwick, 74 at Heathrow, 63 at Manchester, 28 at Stansted, 23 at Luton and 18 at Edinburgh.

The Balearic islands of Majorca and Ibiza appear to be amongst the worst affected.

Bad summer for the industry

Passengers are being advised to check their airline before travelling to their departure airport, although reports indicate that mixed messages are being received. It is another huge blow to the industry, following on from the issues experienced with regards to the terrible wildfires that brought problems only a matter of weeks ago.