In the wake of a recent series of “near-misses” between Russian military aircraft and European civilian aircraft, some have called for the continuous use of transponders during military flights in international airspace. However, neither NATO nor Russia is likely to agree.

SAS aircrafts parked at a remote stand on Arlanda airport north of Stockholm due to a strike among the Scandinavian airline's Swedish cabin crews. Photo: AP

On Dec. 12 Scandinavian media reported that a Russian air force plane had posed a threat to a civilian airliner of the Scandinavian Airlines (SAS). The versions differed in the details — the Russian reconnaissance plane had allegedly entered Swedish or Danish airspace, and there was no consensus on the distance between the military and passenger aircraft. However, all the statements agreed on one point: It was not an isolated incident.

It should be noted that flights of surveillance aircraft along the borders of potential enemies and neutral countries are commonplace. During the Cold War, for instance, the borders of the Warsaw Pact and NATO countries were constantly buzzing.

Such aircraft are veritable control centers, carrying all kinds of surveillance equipment. The crews perform many tasks — from issuing warnings about missile launches to scanning the radio frequencies of the supposed enemy. Typically, these planes were — and still are — accompanied by fighter jets from the country whose border was being patrolled. This was done to prevent any violation of sovereign airspace, however slight, and to demonstrate combat readiness.

It should be noted also that in the period from the 1960s to the 1980s, the Soviet Union and the United States often painted their reconnaissance planes in the colors of civil aircraft and fitted them with civil radar identification systems. Reconnaissance flights have always carried great responsibility for the pilots, since any border incident could lead to extremely undesirable consequences.

One such incident occurred with a scout plane from neutral Sweden on June 13, 1952, when a Swedish DC-3 equipped with the latest radar and photographic equipment was shot down over the Baltic region by a Soviet fighter. The purpose of the mission, as in previous sorties, was to monitor the maneuvers of the Soviet Navy and identify new radar stations. At the same time, the Swedes were working in close collaboration with the U.S. and British militaries.

The U.S. suffered losses, too. Nevertheless, by the early 1960s a certain aerial détente was being observed. The opposing sides tentatively began to abide by certain rules and not invade enemy territory (although the latter had more to do with improved air defense systems).

After the collapse of the Soviet Union, the number of reconnaissance flights initially dropped considerably — but not for long. The complexities of foreign policy were such that the late 2000s saw the reappearance of Russian surveillance aircraft over the Arctic, the Baltic Sea and the Pacific Ocean. To monitor its potential enemies, Russia uses the IL-20M — a highly modernized version of the IL-20, itself a converted IL-18 civilian airliner from the late 1960s. Incidentally, according to official figures, Russia possesses of 20 such aircraft.

Surveillance aircraft flights either for training or “combat” purposes are not a violation of international law. Neither is the siting of a NATO station on Estonian soil to monitor Russian airwaves. The IL-20M, like its foreign analogues, is able to maneuver in international airspace and perform its tasks without violating national borders. Moreover, modern radar tracking systems allow military personnel in the target country to follow the exact route of such aircraft along its borders.

Naturally, the crew of a reconnaissance plane wants to fly as close as possible to the border of the “enemy” country and, if possible, “accidentally” cross over it, which happens to be standard international practice. Such tiny violation checks the reaction of the potential enemy: how quickly it can scramble jets and install new radar tracking stations and air defense systems to counter intruders.

However, such incidents these days have serious diplomatic consequences, for which reason pilots do not do it without orders from above. But a very slight deviation off course of approximately 100-500 meters into a neighboring country’s airspace is difficult to establish unambiguously and later prove, especially if the aircraft’s transponder is switched off. It is the shutdown of this device on board Russian military planes that Western media have seized upon in reports of recent incidents above the Baltic waters.

It should be noted that there is no international regulation requiring the continuous use of transponders during military flights in international airspace. They are simply necessary to automatically transmit flight information to the air traffic controller.

In response to requests from the air traffic controller, the transponder transmits information about the flight altitude and path, the tail number of the aircraft, its exact coordinates, speed and other data. The use of such information is regulated by international rules binding on civil aviation.

However, according to the Chicago Convention on International Civil Aviation of 1944, any military plane is a so-called “state aircraft” and the only requirement for its operation in international airspace is not to impede the navigation of civil aircraft. There are various bilateral agreements, including ones between Russia and the United States, on the inadmissibility of drills simulating mutual aerial attacks or air emergencies, although none stipulates the use of transponders or the provision of flight plans to countries along whose borders the military aircraft are due to fly.

As it happens, military flights over the territory of a foreign state are, by and large, strictly regulated, but we are talking about international space. Moreover, there are no ordinary civil transponders on board many types of military aircraft. They are equipped with complex “friend or foe” coded recognition systems and other means of communication and navigation, and do not require additional civil aviation systems. Unless they want to be identified as a civil airliner.

It is worth noting that the airline SAS admitted that there had been no risk of collision during the Dec. 12 incident.

"In this particular case, no security boundary has been broken," Knut Morten Johansen, Norwegian Communications Manager at SAS, told Swedish news agency TT. "It is therefore important for SAS to say that nobody has been put in danger, both the pilot and traffic management have had control of the situation."

Moreover, on Monday, Dec. 15 Sweden's Foreign Minister Margot Wallström, the “victim” country, said that the disabling of transponders on military planes is not unusual for Swedish aircraft too, thereby acknowledging that it is common practice worldwide.

Characteristically, in the wake of Estonia’s claim that its airspace had been violated on Dec. 9 by Russian military aircraft, Estonian MEP Urmas Paet submitted a draft resolution seeking to prohibit military aircraft from flying with disabled transponders.

However, the proposal is unlikely to be supported by Estonia’s NATO allies. According to official spokesperson of the Russian Ministry of Defense Major General Igor Konashenkov, the last few months have seen a threefold increase in NATO air activity along Russia’s borders. What is more, in line with common practice, NATO pilots also prefer to disable their transponders.

The opinion of the author may not necessarily reflect the position of Russia Direct or its staff.