Back to all the high punctuality overall

High punctuality overall

High punctuality overall


On the punctuality front, skyguide has been given clear and ambitious performance targets by the European Commission for both its en-route and its airport traffic handling. To gain an accurate picture of an air navigation services provider’s performance, however, the delays concerned should be categorised not only by the place where they occur but also by the reasons they occur. Departure delays can have any of a number of causes, only some of which are attributable to the air navigation services provider.



Causes influenceable by the air navigation services provider:

  • Military activities
  • ATC capacity
  • Exceptional events
  • ATC routings
  • ATC staffing
  • ATC infrastructure


Causes beyond the influence of the air navigation services provider:

  • Accident/incident
  • Weather
  • Non-ATC infrastructure
  • Airport capacity
  • Strike action
  • Aircraft de-icing
  • Environmental issues


Air traffic flow management (ATFM) departure delays can occur whenever Eurocontrol’s Network Management Operations Centre (NMOC) predicts that the number of flights scheduled to use a particular sector of airspace during a particular period according to the flight plans submitted will exceed the sector’s capacity. In such an event, the NMOC will intervene to assign specific take-off slots to the individual flights concerned.


Despite the high numbers of flights it handled, skyguide saw only a slight decline in its punctuality in 2018, and 96.5% (prior year: 97%) of all flights were handled without delays. Skyguide thus met the requirements of the European Performance Plan. Average en-route delays per flight increased from the 10.1 seconds of 2017 to 17.1 seconds. These delays were attributable primarily to adverse weather conditions (41%), capacity shortages (39%) and staff absences through sickness (17%).

The reasons for the majority of delays are outside air navigation services’ control. The main causes of the delays at Geneva Airport, which were up 27.9%, were adverse weather (55%), insufficient landing runway capacity (20%), illness-related staff absences (19%) and insufficient approach capacity (3%). The prime reasons for the delays in Zurich, which were up 15.2%, were also adverse weather (56%) and insufficient landing runway capacity (18%), along with environmental constraints (13%) and insufficient approach capacity (10%).


Countering en-route delays
En-route air traffic saw an 82% increase in delays Europe-wide in 2018, largely as a result of external factors. The reasons were:

  • Adverse weather conditions (strong winds) were experienced every month throughout the year and caused more than twice the amount of delays that they had the previous year (+ 139%).
  • In view of personnel shortages at the Karlsruhe, Maastricht and Reims control centres, the European bodies responsible decided to reassign traffic to those centres which had free capacities. Skyguide’s Zurich area control centre (ACC) was thus assigned a substantial amount of additional en-route traffic. This led to capacity shortages. Without this additional burden, the average delay in the airspace of ACC Zurich would have been not 0.32 minutes but only 0.26 minutes per flight.
  • A large number of special provisions throughout Europe brought sizeable volatility to short-term traffic forecasts.
  • In view of the high oil prices, more airlines opted to fly directly over Switzerland, adding to the growth in the amounts of traffic handled by ACC Zurich.


Skyguide has taken actions to increase its system capacities:

  • Harmonised ACC sectorisation for Geneva and Zurich at Flight Level 315 (31 500 feet or 9 600 metres) and above, for which capacity increases were effected.
  • Sector planning tools based on hourly traffic forecasts.
  • Continuous improvement of the systems that forecast traffic loads and flows.
  • Improved flexibility in air traffic controller rostering by expanding their qualifications.
  • New measures to enhance traffic management.
  • Developing a new method to identify flights in different sectors or at different flight levels from those originally planned.
  • A Swiss-wide harmonisation of installations and procedures to permit flexible operating processes (the Virtual Centre).


Skyguide not only demonstrates its performance capabilities to its owners and customers in Switzerland. Since 2012, it has also been required to do so towards the European Commission. And at the end of 2014, the Commission set a series of performance criteria for the 2015-2019 reference period, in consultation with skyguide and the Swiss Federal Office of Civil Aviation (FOCA). The criteria defined by the European Commission prompted controversy within Europe: companies that are as regulated as air navigation services providers are find it difficult to reduce costs, simultaneously invest in new technologies and achieve the targets of the European Performance Plan.