Before dawn on 1 September 1983, a silver Soviet interceptor sat a few hundred metres off the wingtip of a Boeing 747 high above Sakhalin Island. The fighter’s pilot could see the airliner’s flashing lights and its long double row of windows. Minutes later he fired two missiles, and 269 people died in the Sea of Japan.

The aircraft was a Sukhoi Su-15, NATO reporting name Flagon. For a quarter of a century it was the backbone of the Soviet air defence forces, the PVO, built in greater numbers than almost any interceptor of its era and never sold abroad. It was a weapon designed for one job: to climb fast, find an intruder in the dark and destroy it on orders from the ground. Its history shows how efficiently it did that job, and how terribly that efficiency could go wrong.

A Radar With Wings

The Su-15 grew out of Sukhoi’s earlier tailed-delta interceptors, the Su-9 and Su-11. Those single-engine jets breathed through a nose intake with the radar squeezed into the shock cone, which left little room for a bigger set; the Su-11 was also nose-heavy. The answer, tested on a series of experimental airframes, was to move the intakes to the fuselage sides and give the radar the whole nose.

The T-58D prototype first flew on 30 May 1962 with test pilot Vladimir Ilyushin at the controls. It kept the delta wing of its predecessors but added a second engine: two Tumansky R-11F2S-300 turbojets side by side in the rear fuselage. Later Su-15T and Su-15TM aircraft switched to the R-13-300 family, each engine giving roughly 65 to 70 kN (about 14,600 to 15,700 lbf) in afterburner, depending on the source.

The complete interception system, aircraft, radar and missiles together, was accepted for service in April 1965 as the Su-15-98. The early jets carried the Oryol-D58 radar, and the “98” in the designation referred to the missile: the R-98, known to NATO as AA-3 Anab. It came in two versions, one with semi-active radar homing and one with an infrared seeker.

Performance was impressive in a straight line and modest everywhere else. Top speed was about 2,230 km/h (1,386 mph), roughly Mach 2.1, and the service ceiling about 18,000 m (59,000 ft). Range was the weak point, which mattered little to a point-defence fighter that was expected to take off, climb, follow vectors from a ground controller and shoot. The Su-15 was never meant to dogfight, and the first versions had no gun at all.

From Flagon-A to the Su-15TM

Series production began at Novosibirsk in 1966 and the type reached PVO regiments in 1967. The first improvement came in 1969 with a new cranked wing of greater span. A two-seat trainer, the Su-15UT, followed in 1970 without radar or weapons.

The radar was the harder problem. The Su-15T introduced the more powerful Taifun set, but it proved so troublesome that only ten were built. Its successor, the Su-15TM, entered production in December 1971 with the improved Taifun-M; the bigger radar demanded a new nose shape, and later aircraft received the distinctive ogival radome seen on most surviving examples. The TM also gained pylons for short-range R-60 (AA-8 Aphid) missiles and could carry UPK-23-250 pods with a twin-barrel 23 mm cannon.

Production of the armed versions ended in 1975, and the last Su-15, a combat-capable Su-15UM trainer, rolled out in 1979. In total about 1,290 were built, all at Novosibirsk. None were exported: apart from a small number reportedly flown by Soviet crews in Egypt in the 1970s, the Flagon served only the Soviet Union and, after 1991, its successor states. Its main rival for the PVO’s budget, the twin-engine Yakovlev Yak-28P, was judged the weaker aircraft in everything but range.

Guarding the Longest Border on Earth

The Su-15’s job was to stand quick-reaction alert along the Soviet periphery, from the Kola Peninsula to Sakhalin, and to intercept anything that crossed the line. In practice the pilot was one component of a ground-controlled system. Radar stations tracked the target, controllers steered the interceptor to it, and the order to fire came from the ground. The pilot’s own judgement counted for less than the instructions in his headset.

That system had already fired on an airliner once. On 20 April 1978 Korean Air Lines Flight 902, a Boeing 707 bound from Paris to Seoul via Anchorage, strayed far off its polar route and over the militarised Kola Peninsula. A PVO Su-15TM flown by Alexander Bosov intercepted it and, on orders from the ground, fired two missiles. One tore off part of the left wing; two passengers were killed. The captain then landed the crippled 707 on the frozen Lake Korpiyarvi in Soviet Karelia, and 107 people survived. Afterburner told that story in full in Shot Down, Then Landed on a Frozen Lake.

Three years later, on 18 July 1981, a Su-15 pilot named V. A. Kulyapin rammed an Argentine-registered Canadair CL-44 cargo aircraft that had entered Soviet airspace over the Transcaucasus. The freighter crashed, killing its crew; Kulyapin ejected and was decorated. To the PVO, these were successful interceptions.

Sakhalin, 1 September 1983

Korean Air Lines Flight 007, a Boeing 747 flying from Anchorage to Seoul, had been drifting north of its planned track for more than five hours by the time it neared Sakhalin. The International Civil Aviation Organization (ICAO) later found no evidence that the crew knew; its 1993 report concluded that the deviation most likely came from the autopilot being left in heading mode rather than following the inertial navigation route. Soviet fighters had already tried and failed to intercept the jet over Kamchatka.

Over Sakhalin the job fell to Major Gennadi Osipovich, the most experienced pilot on duty at the Sokol air base, flying a Su-15TM under the call sign 805. According to ICAO, ground controllers instructed him to fire warning bursts from his cannon, but the rounds were not visible tracers. Controllers on the ground, ICAO found, assumed the target was an American RC-135 reconnaissance aircraft, and exhaustive efforts to identify it were not made.

As the airliner climbed and slowed on a routine air traffic clearance, the faster interceptor overshot, and the ground ordered Osipovich to attack before the target escaped over international water. He launched both R-98s, one radar-guided and one heat-seeking. According to ICAO, at least one struck the 747 at 18:26 UTC. The airliner remained airborne for about twelve minutes before it fell into the sea off the south-west coast of Sakhalin, near Moneron Island. There were no survivors among the 246 passengers and 23 crew.

Osipovich’s own account shifted over the years. Speaking to The New York Times in 1996, he said he had been alongside at the same altitude, 150 to 200 metres (about 500 to 650 ft) away, and had seen two rows of windows. “I saw two rows of windows and knew that this was a Boeing,” he said, adding that he believed a civilian type could easily be converted for military use. He also admitted a crucial omission.

The Soviet Union first denied, then defended the shootdown. Its divers secretly recovered the flight recorders, which were not handed to ICAO until January 1993, after the USSR had collapsed. The full human story of Flight 007, from the navigation error to the families who waited nine years for answers, is told in Le vol de nuit 007 n'est jamais rentré à la maison.

The Quiet End of the Flagon

The Su-15 was already being replaced when the Soviet Union fell. Newer Su-27 et MiG-31 interceptors took over many of its regiments, and the Conventional Armed Forces in Europe Treaty, which came into force in 1992, demanded deep cuts in combat aircraft. Russia retired its last Flagons by about 1994, and hundreds were cut up for scrap.

Ukraine, which inherited two former PVO regiments, kept flying the type a little longer. Its final Su-15TMs and Su-15UMs were withdrawn at Belbek in Crimea in 1996. No Su-15 flies today; the survivors stand in museums from Moscow to Kyiv and Košice, their green radomes fading in the sun.

As an engineering answer to the problem it was given, the Flagon was sound: fast, simple and built in large numbers to guard an enormous border. Its legacy, though, is tied to a system that put the decision to fire with distant controllers who did not ask the one question that mattered. In May 1984 ICAO’s member states adopted Article 3 bis of the Chicago Convention, recognising that every state must refrain from using weapons against civil aircraft in flight. The Su-15’s name has been linked to that night over Sakhalin ever since.

Sources: International Civil Aviation Organization (1993 report on KE007), The New York Times, The Washington Post (reporting Izvestia), The Christian Science Monitor, Air & Space Forces Magazine, ACIG, Milavia, GlobalSecurity.org, Aerospaceweb, Air Vectors.

Header photo: Sukhoi Su-15TM in Museum of technique 2016-08-16 by Mike1979 Russia, CC BY-SA 4.0, cropped, via Wikimedia Commons