From lakebed to legacy at Patria’s F-35 assembly and maintenance facility

The engine rose from a depth of seven meters 

The Fokker's deceased pilot was found in the water soon after the accident. In the 1980s, parts of the disintegrated aircraft were recovered, but the intact engine remained at the bottom of the lake at a depth of about seven metres.

– The engine had sunk into soft bottom sediment, which first had to be cleared away using pumps. One of the challenges was the almost non-existent visibility, says Simula. .

With lifting straps threaded beneath the engine by a team of professional divers, and using a gantry crane, the engine was raised above the water surface and onto the ice. From there, the Finnish Defence Forces’ NH90 helicopter transported the engine to Millog’s facility in Siikakangas, which is part of the Patria Group.

– After preliminary cleaning, the engine was taken for conservation in Joensuu. Its overall good condition was a positive surprise. Some parts looked as though they had just come from the factory, Simula describes.

Motor's overall good condition was a positive surprise.

According to Simula, the conserved engine is of great value in aviation history, as it is a rare engine type. Only just under 3,000 R-1535 Twin Wasp Jr engines were manufactured worldwide in the 1930s and 1940s. 

– Only a handful have survived to this day. 

Patria made the lifting operation possible

The lifting operation, carried out in late winter 2025, was largely funded by Patria and the engine manufacturer Pratt & Whitney. Patria also supported the operational arrangements of the project. A key partner was the Military Museum of Finland, which provided the permit for working with old military material.

– Patria’s participation in the project was natural, as the Fokker fighter was manufactured at the State Aircraft Factory, Patria’s predecessor, says Patria’s Executive Vice President and retired Major General Engineer Kari Renko. 

The lifting operationwas largely funded by Patria and the engine manufacturer Pratt & Whitney.

Patria’s aircraft history dates back to 1921. In its early years, the aircraft factory operated in Suomenlinna, Helsinki. In the mid-1930s, the factory moved to new premises in Härmälä, Tampere.

– During the war, production was decentralised to Kuorevesi, where the aircraft that crashed into the lake was also built, Renko shares.

The Linnavuori production unit was completed in 1943, and aircraft engine maintenance and repair began there the following year.

After the Second World War, the manufacture and maintenance of military aircraft was transferred to Valmet Aircraft Industry. In 1997, it became part of Patria, when several Finnish defence industry operators merged into one company. 

The Linnavuori production unit was completed in 1943, and in 1997 it became part of the Patria Group.

History comes full circle now in Linnavuori 

Kari Renko believes Linnavuori is an excellent location for the conserved engine, particularly as Pratt & Whitney will supply fighter engines for the Finnish Air Force’s future F-35A fighters. 

Patria is responsible for the assembly, maintenance and upkeep of Pratt & Whitney F135-PW-100 fighter engines in Linnavuori. For this purpose, new production facilities were built on the factory site, originally serving as engine assembly halls and later as maintenance spaces.

As the strategic partner of the Finnish Defence Forces, Patria is responsible for the maintenance of the F-35 fleet throughout the aircrafts’ entire life cycle.

‒ In a way, history comes full circle with Pratt & Whitney fighter engines returning to Finland. Since the Fokker fighters manufactured in the 1940s, such engines have not been in use by the Air Force. However, various types of Pratt & Whitney engines have been used in transport and liaison aircraft, says Renko. 

Read more about Patria's history: 
The foundation for a secure future

Read the news: 
Patria and RTX’s Pratt & Whitney agree on final assembly of the first F135 fighter jet engines for Finland