Airport chaos made worse by homeworking - report

More than 2,000 flights were grounded in August 2023

Allowing an engineer to work from home delayed efforts to resolve Bank Holiday airport chaos caused by a flight data fault, a report has said.

More than 700,000 passengers suffered cancellations and delays in August 2023 due to the computer shutdown at NATS, the UK's air traffic control service.

The engineer was unable to reset the system from home and arrived at work more than three hours after the incident began, the Civil Aviation Authority (CAA) said.

NATS said it would review its resilience plans and had ensured the fault could not happen again.

A single flight from Los Angeles to Paris triggered the failure on Monday 28 August, the CAA report confirmed.

Air traffic control systems handling the flight were confused by a duplicate code - DVL - representing both Deauville in France and Devil's Lake in North Dakota, USA.

The failure was detected at 08:30 BST at NATS headquarters in Swanwick, Hampshire, which contacted the engineer 30 minutes later, the report added.

Unable to resolve the issue after logging on, the engineer arrived at work shortly before 12:00, it said.

The system was eventually restored at 14:30 after its manufacturer Frequentis Comsoft identified the fault.

More than 2,000 flights were cancelled on 28 and 29 August, causing "chaotic conditions" at overcrowded airports, the CAA reported.

It said the total cost of the incident to passengers and air operators was between £75m and £100m.

In a list of recommendations, it said NATS should review its arrangements to manage significant disruption as well as its communication with airlines, remote working policies and software.

Passengers at Belfast International Airport were among those left in limbo

EasyJet chief executive Johan Lundgren said: "The report makes clear once again that airlines and passengers were severely let down by NATS due to its failure of resilience and lack of planning.

"Airlines were then left picking up the pieces and costs, which ran into millions."

The air traffic control system had previously processed more than 15 million flight plans without the scenario being seen.

A NATS spokesman said: "We would like to apologise again for the inconvenience passengers suffered because of this very unusual technical incident.

"Our own internal investigation made 48 recommendations, most of which we have already implemented; these include improving our engagement with our airline and airport customers, our wider contingency and crisis response, and our engineering support processes.

"We fixed the specific issue that caused the problem last year as our first priority and it cannot reoccur."

Transport Secretary Louise Haigh said: "The NATS IT failure last year was an unprecedented event that we all hope never happens again.

"My department will look to introduce reforms, when we can, to provide air travellers with the highest level of protection possible."

Under the Conservative government, in June last year the Department for Transport set out plans to give the CAA "stronger enforcement powers", but no legislation on the issue was introduced to Parliament.

This story was updated on November 22, 2024, to add in more context provided by the CAA.