Cascading Critical Infrastructures: Swanwick Air Traffic Control Center

On December 12, 2014, various media outlets reported on the failure at the Swanwick air traffic control center, south of London, which affected thousands of flights in the United Kingdom and caused delays and cancellations for several days.

What Exactly Happened?

A power outage affected the National Air Traffic Control System (NATS). That is, the organization that manages the information system that provides air traffic controllers with information on each flight.

The unavailability of the system forced controllers to update it manually at London airports. The problem not only left the main system inoperative, but also the emergency systems.

The incident was officially announced by Eurocontrol, the European air safety agency, at 3:30 a.m. local time (4:30 a.m. in Spain). At that time, London’s airspace was practically closed as landings could not be sequenced.

What is the Cascade Effect and how Does it Affect Critical Infrastructures?

A critical infrastructure, such as an air traffic control center, is one whose operation is indispensable and does not allow for alternative solutions, so its disruption or destruction has a serious impact on essential services. These infrastructures are characterized by:

• Having adopted a high level of automation for its operation and/or control.
• Being exposed to a high number and types of threats.
• Being, in most cases, geographically distributed, even in different nations.
• There is a high degree of interrelation between them all. That is, as we have seen, the failure in the power supply to the system caused its collapse, generating chaos in London airports. This type of dependency is what is known as the cascade effect, which specifically affects critical infrastructures.

What Type of Technology Has been Deployed in NATS?

The NATS organization is currently using a cloud computing-based platform with Citrix Desktop and XenApp, in addition to other virtualization tools. However, these systems have not been linked to such a fall.

What Consequences Has the System Failure Had?

• The problem forced the partial closure of London’s airspace.
• At the airports of Gatwick, Luton, Heathrow and Stanstead, takeoffs were also temporarily suspended as a precaution.
• London’s fifth airport, City, the closest to the city, basically suspended activity on its runways for two hours.
• In Leeds, all flights were suspended for three hours. Bristol, Southampton and Oxford were initially the most affected.
• The effects were felt even in the Scottish airports of Edinburgh and Aberdeen.

What is Being Done in Spain to Try to Avoid this Type of Problem?

In Spain, the Critical Infrastructure Protection Law (Law PIC 8/2011), complemented by Royal Decree 704/2011, has two main objectives:

• Those of cataloging the set of infrastructures that provide essential services to our society.
• To design a plan that contains effective prevention and protection measures against possible threats to such infrastructures, both in terms of physical security and in terms of the security of information and communication technologies.

Within this planning, the Operator Security Plans (PSO) oblige organizations that manage infrastructures classified as critical to carry out a quantitative risk assessment, which must include a modeling of the dependencies existing between the different critical infrastructures.

For more information on the PIC Law, you can visit this link.