The Sukhoi Su-15 (NATO reporting name Flagon) was a twin-engined interceptor aircraft developed by the Soviet Union in the 1960s to replace the Sukhoi Su-11. As one of the V-PVO's principal interceptors, the Su-15 was involved in a number of incidents with foreign aircraft. One such attack was in 1978, when Korean Air Flight 902 was attacked over Murmansk by a PVO Su-15. Although the civilian aircraft survived the missile hit, it subsequently crashed, killing two passengers. In 1981 a Baku, Azerbaijan-based Su-15 rammed an Iranian Canadair CL-44, apparently as a deliberate attack. More notorious was the Korean Air Flight 007 incident in 1983, when a Korean Boeing 747 was shot down by a Su-15TM based on Sakhalin, killing all 246 passengers and 23 crew. Other incidents involving reconnaissance and surveillance aircraft may have occurred, but gone unrecorded.