Due to Finland’s northern location and long winter season, airport operations cannot be put on hold when snowfall, slippery conditions or a sudden change in weather occurs. The importance of safety is emphasised in winter conditions, and close cooperation between airport operators is needed in order to achieve this. Fintraffic's Air Navigation Services maintains and distributes a real-time situational picture of weather and runway conditions, regulates the capacity of air traffic in challenging weather and anticipates the impacts of weather conditions on both the ground and in the air.
In winter, air traffic is challenged by freezing rain, which freezes on aircraft, ground equipment and runways, along with wet snow and accumulated snow and ice. In addition, rapid temperature fluctuations pose their own challenges. However, slippery conditions, the condition of runways and the wind direction relative to the runway in slippery weather conditions have the greatest impact on the safety and smooth running of air traffic during the winter season.
“Runways are primarily available at all times in the summer, and their closure can be anticipated well in advance, such as for maintenance. In the winter, runways may have to be closed due to the weather and the resulting clearance work even on short notice if the conditions suddenly change. This affects both incoming and outgoing flights, and has a knock-on effect throughout all air traffic operations. There are so many variables, but Finland is one of the best in the world at managing this,” says ATCC Director Karri Hannula of Fintraffic's Air Navigation Services.
It is the task of air traffic control to anticipate the effects of winter weather conditions and runway closures on the ground and in the air. If necessary, air traffic is controlled to provide realistic runway time for each arriving and departing flight.
In winter conditions, close cooperation between airport operators is needed
The importance of cooperation and information flow between air traffic control and other airport operators is emphasised during the winter season, as conditions may change rapidly. For example, the predictability of outbound traffic deteriorates in winter because, in addition to the weather conditions on the runway, the time it takes for aircraft to be cleared of snow and de-iced must also be taken into account.
“We only have minutes to get flights to de-icing at the right time and then out to the runway ready for departure. If the conditions on the runway suddenly change while the aircraft is being cleared off or it’s taking longer to prep it than expected, things can back up quickly. In such varying weather conditions, airlines sometimes board passengers in advance. It can be frustrating for passengers to wait on board, but in challenging weather conditions, things are constantly changing. In some cases, a departure slot might suddenly open up, making it possible for the aircraft to take off right away because the passengers are already on board,” explains Hannula.
An important part of preparedness is the situational picture maintained by the air traffic control centre
At airports, preparations are made for the winter season well in advance, such as by increasing personnel and equipment resources where needed. An important part of preparedness is also the shared situational picture of weather and runway conditions maintained by the air traffic control centre 24 hours a day. In more challenging weather conditions, we sit down together with various airport operators to create a situational picture and forecast as well as go over the airport’s capacity.
“Based on this jointly created situational picture, airlines can make decisions on, for example, flight cancellations, and we in air traffic control think about what kinds of control measures we need to regulate air traffic. When the conditions change, air traffic control will, if necessary, make changes to previously set plans to ensure that air traffic is as safe as possible, even in variable conditions,” adds Hannula.
