KEA is a key performance indicator measuring the level of horizontal en-route flight inefficiency in actually flown trajectories over a period of 12 months.

Please note that the values are NOT monthly averages but the average over the entire 12 months period preceding the last day of the month

In order to smooth out the influence of unusual events, the ten best days and the ten worst days (for each measured area) are excluded from the computation.

The key performance indicator is used in the Single European Sky (SES) Performance Scheme.

More information on the methodology used to compute Horizontal en-route flight efficiency .