Measuring safety: performance indicators

In air navigation services it is never easy to collect – or interpret – meaningful data on safety. As in other high-safety-level industries, there are only very few incidents to analyse, so statistics on negative events are not very helpful in anticipating long-term developments.

In addition to this, every country collects data differently, which also makes cross-comparison difficult.


However, it is nonetheless important to be aware of developments in safety. To this end, in 2010 skyguide developed a “cockpit” with over 30 indicators. As well as internationally used indicators, it also collects data on, for example, the timing and quality of long-planned measures or short-term improvements as well as qualitative risk assessments.


The safety cockpit is presented to the Executive Board on a quarterly basis so that trends and “hotspots”, as well as prompt corrective action on any weak spots, can be discussed. In addition, the most important indicators and findings are reviewed each quarter by the competent Committee of the Board of Directors.


Assessments performed over time have shown positive trends, for example:

  • The continuous decline in separation minima infringements
  • Stability of operation and of technical systems (stabilising phase of new processes and system components not taken into account)
  • A stable resource situation for the implementation of improvement measures
  • The existence for many years of a very good reporting culture


In spite of the inadequacies of the statistics, even small, sporadic deviations and isolated local risks are systematically investigated: statistics cannot be allowed to gloss over critical observations.



At an international level, from Brittany to Switzerland and from Corsica to the North Sea, FABEC (the Functional Airspace Block Europe Central) has for some years also been collecting figures on the safety of civil air navigation services. Even though the paucity of currently available datasets makes it impossible to record any definitive development, from a statistical point of view, this much larger sample (eight and a half times more flights than for Switzerland alone) constitutes an interesting source for the longer term.


Also of primary importance are: international harmonisation in relation to safety indicators, targets and best methods, and the pooling of strengths to achieve the highest possible levels of safety in air navigation services.


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