WATCH: Two American F-35 jets arrive at Pirkkala after delayed Atlantic crossing

The Lockheed-Martin aircraft are the latest land in Finland and be put through their paces, with a €10 billion contract at stake.

File picture of F-35A Lightning / Credit: Billie Flynn Twitter

Two F-35A Lightning fighter jets built by American manufacturer Lockheed Martin have arrived at Pirkkala Air Base, to being a week of intensive testing and evaluation.

The jets landed on Sunday evening, their arrival delayed by bad weather on the flight from USA to England, and then onward to Finnish air space.

Four F-35s initially left Luke Air Force Base in Arizona on 5th February and headed east but refueling tankers couldn’t support the mission across the Atlantic due to the weather conditions, and just two jets ended up in Pirkkala.

“We’re thrilled to be able to show what the F-35 can do, its amazing capabilities, and what it will be like as part of the future of the Finnish Defence forces now, and for the many decades to come” says Lockheed Martin test pilot Bille Flynn in a short video posted to social media.

Watch: Two F-35A Lightning jets land in the dark on Sunday night at Pirkkala Air Base

What’s happening at Pirkkala Air Base? 

The aircraft will take part in simulated long-term war games, where the candidate jets will play their roles as part of Finland’s defence systems. In the simulated battles they’ll face the Air Force’s current F/A-18 Hornets and Hawk jet trainers.

The Air Force says the event is taking place in Finland so that each plane can be tested under Finnish winter operating conditions – and also to provide a balanced evaluation for each of the five candidate aircraft.

The other contenders taking part in ‘Operation HX Challenge’ are France’s Rafale; the Eurofighter’s Typhoon; Boeing’s F/A-18 Super Hornet; and Sweden’s Saab Gripen.

Although all the aircraft are designed to operate in sub-zero temperatures, the Air Force says when temperatures hover around zero with snow, sleet or freezing drizzle, it throws up extra challenges for the jets.

Harsh weather conditions can have an impact on the performance of electro-optical sensors in particular.