More than 50 military planes and helicopters are flying over Finland – sometimes low over inhabited areas – over the next week as part of the Air Force's main annual exercise. The event is known as Ruska, referring to the colours of autumn foliage.
The Finnish Defence Forces (FDF) warned the public that the exercise's low-level and supersonic flights may trigger audible sonic booms. Meanwhile countermeasures such as flares and chaff may show up as bright spots in the sky and echoes on weather radar.
Gripens on display
Flight operations began at noon on Tuesday and continue through the following Tuesday, 8 October. The heaviest phase of will be begin on Friday, with operations daily between 8 am and 10 pm for five days.
Most of the operations centre around air bases in Tampere, Jyväskylä, Kuopio and Rovaniemi. Nearly half of the personnel taking part are reservists.
Finnish aircraft taking part include Hornet and Hawk fighter jets, transport planes and an Army helicopter. Sweden is participating with a Canadian-built Argus reconnaissance aircraft and eight Saab JAS 39 Gripen fighters – which Sweden hopes Finland will order to replace its ageing fleet of US-made Hornets. Those in Finnish airspace this week are C/D models while those on offer to the FDF are the newer E models, which were first tested in 2017.
Two years ago, US President Donald Trump caused a stir by erroneously announcing that Finland was buying "a large number" of new Hornet fighter jets.
Reds vs Blues
The FDF is tight-lipped about the scenario involved in the war games. According to Helsingin Sanomat, participants are divided into defending forces known as "the Blues" and attackers dubbed "the Reds". The latter are based in the northern cities of Rovaniemi and Oulu as well as Luleå on the coast of Swedish Lapland.
The FDF says that Swedish planes "will fly in both the defending and the adversary units of the exercise," and be based in Luleå and Kuopio.
The Finnish and Swedish air forces have regularly taken part in each other's exercises since 2016.
Unlike neighbouring countries such as Norway, Denmark and Estonia, the two countries are not Nato members. However Finland and Sweden both hold 'enhanced membership' in Nato's Partnership for Peace programme, and frequently take part in Nato-led exercises and operations.
The exercise starts as news broke that the headquarters of Sweden's navy had returned to a vast underground base used during the Cold War, with the Swedish military citing a 'deteriorating external environment' as grounds for the decision.