Russian Military Planes, Flying With Transponders Off, Provoke Alarm in Europe

In the latest in series of aggressive maneuvers by Russian military planes in European airspace, the Financial Times is reporting today that a Russian intelligence plane nearly caused a mid-air collision with a Swedish passenger jet on Friday while flying along a Flight Information Region (FIR) boundary with its transponder turned off.

An SAS jet taking off from Copenhagen on Friday was warned by Swedish air traffic control to change course to avoid a Russian military intelligence flight, said Swedish authorities.

Peter Hultqvist, Sweden’s defence minister, said it was “serious, inappropriate and downright dangerous” that the Russian aircraft was flying with its transponder — used to identify its position — switched off. He told Swedish reporters: “It is remarkable and very serious. There is a risk of accidents that could ultimately lead to deaths.”

The incident is the latest in a series involving Russian military aircraft over the Baltic Sea this year. In March, an SAS airliner came within 100 metres of a Russian military aircraft shortly after take-off from Copenhagen, Swedish television reported.

In the most recent incident, the Swedish and Danish military detected the Russian aircraft in international airspace on radar and warned the SAS flight, said to have been bound for Poznan, Poland.

A story about the incident in WAtoday links to a YouTube clip of ATC audio combined with speeded-up playback the commercial flight from Flightradar24.com, which indicates that the incident took place near the boundary between two FIR zones, Sweden and Rhein-UIR, with the Russian plane flying west to east along the boundary.

As I wrote in an earlier post, military pilots have been known to fly along FIR boundaries with their transponders turned off as a means of escaping detection. In what may or may not have been a coincidence, after it deviated from its planned course to Beijing, MH370 flew along the FIR boundary between Malaysia and Thailand with its transponder turned off. The pilot in Friday’s incident may have been testing NATO air defense systems to see how well the technique might work over busy Europeans airspace.