Cooperation to ensure safer international airspace over the Baltic Sea

Ministry of Transport and Communications
Publication date 13.1.2015 12.16
Press release

So-called invisible military aircraft that fly through international airspace above the Baltic Sea pose a risk of collisions. The issue came to public light in December, when it was reported that numerous EU Member States had observed military planes the transponders of which were turned off and to which no radio contact could be made.

According to the International Civil Aviation Organization's (ICAO) Convention on International Civil Aviation every country is responsible for ensuring that the country's military aviation does not cause a danger to civil aviation. The responsibility also applies outside of the country's borders.

Minister of Transport and Local Government Paula Risikko stated in mid-December that aircraft flying in international airspace must keep their transponders tuned on and, when necessary, be in radio contact with other aircraft.

"It is in the interests of the global aviation community and all air travellers that there are no "invisible" flights. I want Finland to take an active role in this matter in international aviation forums, so that we can ensure the safety of civilian aviation in all situations," Minister Risikko said.

At Minister Risikko's request Trafi has initiated measures to minimise the safety risks caused by "invisible" flights. Success will require broad-scoped cooperation from the entire international aviation community.

Trafi has been in contact with the heads of aviation in the countries around the Baltic Sea about this matter and highlighted the issue within the European Aviation Safety Agency (EASA), the European Commission and the International Civil Aviation Organization (ICAO). The objective is to see to it that the matter is discussed at all levels and that each country does its part to ensure aviation safety.

Trafi's letter on 12 January 2015 to the heads of aviation in countries around the Baltic Sea emphasises the safety risk posed by "invisible" flights, as well as the importance of each flight's safety elements. These include a flight plan approved by air traffic control, radio contact with air traffic control and the use of the aircraft's transponder.

"With regard to safety, it is of primary importance that the aviation authorities in different countries work in close cooperation, and that within the scope of all their activities all actors, including state-owned, comply responsibly with jointly agreed upon rules. Compliance with internationally agreed upon measures is a key element of safety," emphasises Pekka Henttu Director General of Aviation at Trafi.

The European Aviation Safety Agency (EASA) has collected data from countries around the Baltic Sea on the safety risks caused by unidentified aircrafts and the behaviour of the planes. The EASA is now drafting a report on the subject, which will also be submitted to the Secretary General of the ICAO for further measures.

Further information:

Mr Pekka Henttu, Director General - Aviation, Trafi, tel. +358 29 5346 031
Ms Hanna Tapala, Special Adviser to Minister Risikko, tel. +358 41 544 9500


"Invisible" flight

An invisible flight refers to an aircraft that does not have a flight plan logged with air traffic control, is not in radio contact with air traffic control and does not have its transponder turned on. Such an aircraft is not visible on air traffic control radars, and the traffic collision avoidance system (TCAS) will not function. An "invisible" flight is visible on military radars (surveillance radar. when within the area covered by the radar and not in a blind area. A flight that is not in radio contact with air traffic control and that has its transponder turned off is not considered invisible, if the flight is appropriately coordinated with air traffic control and it has a plan to prevent collisions.


A transponder increases aviation safety. Only aircraft equipped with transponders are visible on air traffic control's screens. The radar system for civilian aviation thus functions under a different principle than primary surveillance radars used by the military. These can also spot other mobile airborne objects, such as flocks of birds. A transponder sends air traffic control information on the aircraft's speed, altitude and direction of flight. Additionally, TCAS equipment (traffic collision avoidance system), which are used especially by commercial air traffic, need a transponder signal in order to be able to supply instructions for avoiding a collision.