Weather conditions and their impact on air traffic

We live in a climate zone characterised by four seasons and their specific features, which in the worst case can also affect air traffic. Let’s find out a little about the main weather conditions affecting air traffic and what they can bring along.

Snowfall and freezing rain

Just as heavy snowfall and freezing rain can affect regular traffic, they can also affect air traffic.

Safety is the airport’s number one priority and during the winter period, this means uninterrupted snow clearing and keeping the runway and aprons clean – our staff work on this 24/7. Keeping the runway clean and open is easy under normal circumstances, but it can become difficult in extreme weather conditions (such as heavy and wet snow or freezing rain). If keeping the friction coefficient of the runway cannot be kept at a good enough level, aircraft will not be able to land. In this case, the runway will be closed, which may lead to flight cancellations and delays or flights being diverted to alternate airports.

There are also situations where the runway is open and clear, but the pilot decides not to land in Tallinn. It must always be remembered that the decision to land is always made by the flight crew with the safety of passengers in mind. The flight hours of the crew and the type, age and technical capability of the aircraft are also taken into account. If the aircraft cannot land at the destination, the pilot may return to the airport of departure or the nearest alternate airport.

Fog

Air traffic can also be affected by thick fog, which can cause limited or very poor visibility. Establishing visual contact with the runway to ensure a safe landing is extremely important when landing.

When there is fog outside, landing systems can be deployed to help the aircraft land safely. Instrument landing systems operating by two different principles are available for use by aircraft crews:

• The precise landing system ILS is a system based on information from ground-based devices at the airport, the localiser and the glideslope.
• In the case of the satellite-based landing system, or RNP, there is no additional equipment at the airport and the equipment on board the aircraft uses signals from satellites to land.

Today, Tallinn Airport uses category II landing, where the decision height for the pilot at which the runway or runway lights should be visible is 30 metres and the visibility on the runway is 350 metres. Tallinn Airport introduced category II in the beginning of 2024. Raising the category improved the use of airport infrastructure and runway capacity even in difficult weather conditions.

If the above conditions are not met, the pilot must fly an extra lap and try to approach the runway again in the hope that weather conditions will improve. The decision to land is always made by the flight crew with the safety of passengers in mind. The flight hours of the crew and the existence of modern systems on the aircraft are also taken into account. If the aircraft cannot land at the destination, the pilot may return to the airport of departure or the nearest alternate airport.

Strong wind

Aircraft always take off and land against the wind. On the one hand, wind can be useful, for example, by helping to reduce flight times in favourable circumstances. On the other hand, strong crosswind can be dangerous when an aircraft is landing and it can disrupt air traffic. Prevailing wind directions are also observed wherever possible when runways are built and crosswinds that disrupt air traffic are extremely rare in Tallinn.

The pilot the a decision on safe landing on the basis of the weather, including wind, information provided to the flight crew. If the pilot finds the situation even slightly unsafe, he or she may decide to return to the airport of departure or the nearest alternate airport.

Volcanic ash and sandstorms

Fortunately, these are very rare phenomena in our neck of the woods, but volcanic ash and sandstorms can also lead to air traffic disruption, and not only because of limited visibility. Volcanic ash, for example, is abrasive and can cause severe damage to aircraft engines, which in the worst case can stop working. In addition to this, ash and fine grains of sand can damage the accuracy of airspeed sensors, block the pilots’ view and pollute cabin air.

Reminder for passengers! If the weather conditions are difficult, we advise you follow the information on the airport website and given by the airline.

Have a safe flight and see you again at the cosiest airport in the world!