Four Italian Air Force Lockheed Martin F-35A (reg. MM7357, MM7360, MM7361, MM7362) belong to the 13° Gruppo (Squadron) of the 32° Stormo (Wing) from Amendola AB took off and landed at the Ämari Air Base. During the journey, fighters passed the Suwalki Corridor in Poland.
The web site itamilradar published the route.
The corridor that they passed is controlled by the S-400 Triumf Air Defence Systems radars deployed at Kaliningrad. They may easily obtain radar signatures of the F-35s from such distance.
To the military planners of NATO, the border area is known as the Suwalki Gap. It represents a tough-to-defend flat, narrow piece of land, a gap between Belarus and Russia’s Kaliningrad exclave, and that connects the NATO-member Baltic States to Poland and the rest of NATO. Furthermore, it is known that the Russian Defence Ministry had S-400 “Triumph” systems in Pskov. There is news that some crews are deployed elsewhere, but there is no exact figure available. Psikov is 350 km away from the Ämari Air Base.
Most probably, F35s had the Lunenburg lens active or could use other electronic warfare countermeasures as a precaution. However, the fighters will be on “Secure the Skies” duty for six months. Turkey may bring the issue to the discussion table as a counter-example of S-400 / F-35 co-existence in the same region.