It is also common, according to Tarien, for hostile aircraft, often on reconnaissance missions, to have their transponders switched off. This requires allied interceptors to conduct visual identification flights.

Tarien was speaking in the aftermath of last Friday's incident where three Russian MiG-31 fighter jets entered Estonian airspace near the island of Vaindloo without authorization, remaining in Estonian airspace for around 12 minutes.

The aircraft had filed no flight plans, their transponders were switched off, and they had no bilateral radio contact with Estonian air traffic control at the time of the incursion.

Tarien, currently business manager at drone manufacturer Lendurai, told Välisilm that incidents like this "Happen often enough. When Russian fighters are flying over international waters, the only reason to intercept is if they don't file a flight plan or switch on their transponders. In that case, interception is standard procedure.

On Friday, it is likely Finnish authorities notified Estonia of the Russian MiG flights even before they entered Estonian airspace, meaning Italian Air Force NATO jets based at Ämari which scrambled in response may have done so before the Russian planes did violate Estonian airspace, Tarien went on.

While the exact response time is classified information, NATO jets flying from Ämari can reach a target "within minutes," the expert added.

"There are different readiness levels. The highest is combat air patrol, where the aircraft are already airborne and can respond immediately — but that would be extremely costly and inefficient in peacetime. The next level has jets with engines running at the end of the runway and pilots in the cockpit at all times — also very costly. The typical peacetime readiness level is to have the aircraft in a hangar, with pilots nearby ready to start engines. As soon as the alert comes in, they scramble. The exact number of minutes within which they must take off is classified, but we're talking about just a few minutes before they're airborne and en route to the target," Tarien explained.

Finland and Sweden becoming NATO members in recent years has also helped with response capabilities when it comes to Russian flight incursions.

"We spot the aircraft from a sufficient distance to respond. Now that Finland has been a NATO member for over a year, coordination has become much easier. If Russian fighter jets switch on their transponders, submit a flight plan, and communicate with Estonian air traffic control, there's no reason to intercept them. Unfortunately, they frequently don't do that. For this reason the Finnish side had already moved to identify the suspicious flight, even though it had not yet entered NATO airspace. Three MiG-31s without transponders meet the criteria for an interception. Once they entered Estonian airspace, the Italian jets stationed here as part of NATO's Baltic Air Policing mission were immediately scrambled."

Allied aircraft's peacetime role is in any case to identify unauthorized aircraft, attempt to get the pilots' attention, and prompt them to respond to calls, Tarien noted.

"They get on their tail, and there's an international emergency frequency that all pilots and aircraft are supposed to monitor. The NATO crew announces: 'We are a NATO air policing flight, and we've come to identify you — please identify yourself.' If there's no immediate reaction or visible threat, they usually take a photo."

This is done by "one aircraft in the pair flying alongside the target, while the other snaps a picture to verify the exact location — since our own aircraft is right there and we know its position," Tarien outlined.

"Once that photo is taken, if there's still no response to radio calls, further attempts are made to establish contact — using hand signals or wing waving, for example. Generally, in peacetime and over international waters, we don't go as far as cutting across flight paths. With fighter jets, that's also impractical because they are so maneuverable. Flying beneath them won't yield much. In fact, it's dangerous. If there's no confirmed military threat, the situation remains at the level of escorting. If a threat were identified, then the procedures would escalate—up to warning shots and potentially shooting down the aircraft," Tarien said.

As for calls for transitioning the NATO air policing mission into a full air defense mission, this would involve different rules of engagement, Tarien noted.

"The differences come down to how actions are carried out, who has the authority to use force, and the standards a flight must meet to warrant a response. That's the distinction. I can only speak in general terms, as the exact procedures are, of course, classified."

The incursion prompted Estonia to call for NATO Treaty Article Four consultations, less than two weeks after Poland had done so following a mass Russian drone incursion into its airspace. Western allies condemned Russia's actions at an emergency meeting of the United Nations Security Council on Monday.

--

Follow ERR News on Facebook and X and never miss an update!