Independent investigation into the Skyguide incident of 15 June concluded

Bern, 19.12.2022 - The Federal Department of the Environment, Transport, Energy and Communications (DETEC) commissioned an external investigation into the incident on 15 June 2022 in which Skyguide closed Swiss airspace due to a technical malfunction. The investigation concluded that Skyguide's decision was appropriate and that crisis management had worked well. Skyguide carried out a careful and detailed internal review of the incident in which it identified potential for improving its network infrastructure. This was also confirmed by the external investigation. The independent investigation report contains more than a dozen recommendations for improving air traffic control.

On 15 June 2022, the Swiss air navigation service provider, Skyguide, experienced a technical malfunction. For safety reasons, it subsequently decided to close the airspace it was monitoring (known as 'clear the sky'), denying new air traffic entry into its designated airspace for approximately five hours. Skyguide then initiated an internal investigation into the reasons for the incident and subsequently informed the DETEC. Due to the seriousness of the incident, the DETEC decided to have the facts and results of the investigation examined by an external independent body. The contract for this went to Accenture.

The results of this external investigation are now available. They conclude that Skyguide had established a comprehensive crisis management strategy that it efficiently and effectively implemented on 15 June 2022. The decision to close Switzerland's airspace was appropriate as it was not possible to predict the severity of the disruption or how long it would take to resolve. The investigation also highlights the fact that Skyguide carried out a detailed internal review of the incident and that the points and recommendations identified in Skyguide's internal report are valid and useful.

The independent investigation confirmed that the malfunction was caused by a defect in a network switch; the network component did not have the latest version of software. Although Skyguide does have a functioning process to update network components, this process is overly risk-based and too cautious in the opinion of the independent investigators. It is possible that the incident of 15 June 2022 could have been prevented by updating the software earlier. Skyguide also lacks end-to-end network monitoring, which could have contributed to a more efficient analysis of the error on 15 June and thus possibly led to a faster rectification of the malfunction.

The independent investigation report contains 14 recommendations. They include setting up a business continuity management system (BCMS) to better protect processes and systems critical to air traffic control and to enable alternative operations. Measures should be developed as part of a comprehensive disaster recovery strategy to be initiated after the failure of IT components. These recommendations aim to shorten the time between an outage and the resumption of air traffic control. The report further recommends reinforcing the operational processes for network crisis management and optimising the management of firmware upgrades. The training processes for network technologies should also be improved and the necessary skills in relation to the new technologies used by Skyguide reassessed.

Furthermore, information on the availability of systems to air traffic controllers should be optimised and the emergency checklist for their supervisors adapted.

Skyguide has already begun to implement a number of measures on the basis of its own investigation. Skyguide will now also implement the recommendations from the DETEC's independent investigation to ensure commercial aviation in Switzerland maintains its high standard of safety and that air navigation services remain robust enough to cope with growing complexity.

Address for enquiries

Communication DETEC, +41 58 462 55 11


General Secretariat of the Federal Department of Environment, Transport, Energy and Communications; General Secretariat DETEC

Federal Office of Civil Aviation