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Improving safety: continuous learning

Improving safety: continuous learning


Serious incidents and air accidents are investigated by the Swiss Transportation Safety Investigation Board (STSB). Where there is military involvement, the military judiciary, with the help of external experts, is responsible for technical clarifications.


Skyguide supports all these independent bodies with data and expertise, and does so regardless of whether an error on the part of air navigation services might have occurred. The purpose of technical investigations is not to apportion blame, but to improve the system as a whole.


Not only the reporting and investigation of observations, but also lively national and international exchanges between experts, and more thorough investigation of apparently functioning operations – all these aspects and more help to improve safety. Here are a few examples.


Separation of civil aircraft


Skyguide also investigates more minor incidents that might initially seem irrelevant. For example, its radar system automatically records not only actual near-misses between two aircraft but also infringements of so-called separation minima. The air traffic controllers then provide additional information via a report.


Separation minima infringement (SMI)


A separation minimum is infringed when an aircraft is flown at less than the minimum distance that must be maintained between two aircraft. For aircraft en route the minimum vertical distance is 1000 feet (305 metres) and the minimum horizontal distance – when two aircraft are travelling at the same altitude – is 5 nautical miles (9.26 kilometres).


In fact, individual incidents (of which there are approximatively 10 per 100,000 flights) are seldom problematic. However, increases in the number of such events at a particular location or point in time, or certain patterns being identified, can be clear indicators of an underlying problem.


On the ground, too, taxiing aircraft must be kept apart from one another. Precise separation minima cannot, of course, be applied on the ground. Air traffic control makes sure that runways are free for aircraft taking off and landing. Crossing of safety lines and runways is only possible with the express permission of air traffic control. At the international airports of Geneva and Zurich, the air traffic controllers are supported by the most advanced safety systems in the world. Runway incursions are therefore extremely infrequent.


Runway Incursion


Safety in military operations


The approach to military flight operations is different from the approach to civil flight operations. For the air traffic controllers at a military airfield it is, of course, still about assuring the efficient take-off and landing of aircraft, and guiding those aircraft en route to and from their destination or place of deployment. Civil aviation standards apply, in any case, when airspace used by civil aircraft is crossed.


The difference becomes apparent when missions are flown. In the case of combat exercises, or when the air police are deployed, the air traffic controllers guide military pilots to other objects and offer tactical assistance. Here too, sufficient separation is important, although it is not the main objective. In military aviation, it is the effectiveness of the mission that matters. Accordingly, it is a different understanding of risk that defines the framework for operations. Within this framework, safety standards are adhered to equally systematically.


Skyguide investigates also military or mixed civilian-military incidents and accidents internally, using the data available to it. For example, during the investigations into the tragic accident involving an F/A-18 in the summer of 2016, it was possible to devise various improvements even before the official report was published.


Skyguide works within the common “safety investigation management” in close collaboration with the Air Force safety experts. Paths of communication are intentionally short here, which allows joint investigations and promotes dialogue relating to safety issues.




Technical availability and safety of systems

In exactly the same way as modern aircraft, modern air navigation services rely increasingly on technical systems. Advancing digitalisation brings many advantages, such as the automation of standard processes during which people constitute a greater risk factor than machines. However, this means that the technical systems also need to offer high levels of reliability and availability. For all radar, navigation, communication and air traffic management systems, the target values for failures are a maximum of 80 hours accumulated over two years. For failures in instrument landing systems (ILS Category 3) in Geneva and Zurich a maximum of 12 hours accumulated over one year applies, if there is an impact on the operation.


In the case of most failures, downtime is limited and the fall-back systems take over seamlessly. Should there be major problems with a system, however, procedures apply that allow reduced operations to be maintained: in the worst cases, this leads to delays, but never to compromises in safety.


In the same way as incidents during operations, technical failures are taken very seriously. Longer failures and recurrent irregularities in particular are the subject of in-depth analyses. The results flow into software development, the maintenance process and the procurement cycle, but also into operational processes.



A safe airspace for the next generation

In recent years, the Swiss Transportation Safety Investigation Board (STSB) has repeatedly identified a safety deficit that can only be partially mitigated by operational or technical means, or through training: that deficit is in the airspace structure. Certain parts of Switzerland’s airspace are currently extremely complex, and tax the safety system to its limits. As a result, error tolerance for pilots and air traffic controllers is reduced, and incidents are increasing. It’s time for a radical new start on a fresh page, and the Swiss Federal Office for Civil Aviation (FOCA) is currently undertaking a comprehensive restructuring of airspace and aviation infrastructures. It is thus marking an end to merely treating symptoms and, together with all the other interested parties, is tackling the problem at its root. Interview with Christian Hegner, Director-General of FOCA.


Drones are everywhere; drones are the future

The aeroplane is one of the safest means of transport, and it should stay that way, even with the current massive surge in unmanned devices, or drones. Together with partners in the industry, and the support of the Swiss Federal Office of Civil Aviation, skyguide has developed a system with which these drones can be safely and efficiently integrated into urban airspace.


A so-called U-Space rovides the digital infrastructures, services and processes that enable the drones to access the airspace and, at the same time, assure the safety of other users.
Skyguide is right at the forefront of the development of such systems, as drones have a promising future and, by 2025, will have a fully automatic, networked and digital infrastructure ready for U-Space.


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