Nato fighter jets intercepted a Russian military transport aircraft flying over the Baltic Sea on Monday.
The Russian AN-22 transport had its transponder switched off. The transponder receives radio signals from radar and sends back a squawk code with information about the aircraft’s position, altitude and identification. Without the squawk code, the aircraft appears as an unidentified radar blip. Essentially, the Russian military plane was hiding itself.
Full article: Russian Fighter Jet Intercepted Over Baltic With Transponder Off (The Trumpet)