The Islamic Republic of Iran Air Force operated a single Simorgh, a former Iraqi Air Force Adnan. The Adnan AWACS was in turn a modification of a Soviet-built Ilyushin Il-76 transport.
The Simorgh collided with one of the Air Force's Northrop F-5E Tiger II fighters over the area of the Imam Khomeyni Shrine, southern Tehran. According to eyewitnesses, the crash occurred immediately after the parade. Apparently, no mayday call was issued.
Both aircraft crashed in flames. Initial reports indicate that seven crewmembers were killed in the crash.
In total, Iraq built three AWACS aircraft, one Baghdad, and two Baghdad-2s, the latter later renamed Adnans. One Adnan and the Baghdad were evacuated to Iran during the 1991 Gulf War, while the second Adnan was destroyed on the ground by a coalition air strike in January 1991.
The exact status of the Iranian Simorgh and its onboard systems was long uncertain. However, photographs suggest that the aircraft was equipped with a newly fitted functioning radar suite.