the bomb could be armed and released, to prevent unauthorized uses of nuclear weaponry. The aircraft also has a toss bombing capability for nuclear weapon delivery, with which it could approach the target, initiate a steep climb and release the bomb when pointing almost upright, and then activate afterburners to escape the blast radius. A special IAB-500 bomb was made specifically for practicing such a bombing technique. Operational history Soviet Union/Russia The Su-17M3/4 were used during the First Chechen War alongside Sukhoi Su-24s and Sukhoi Su-25s in ground attack and reconnaissance missions. In a move to eliminate single-engine strike aircraft from its inventory, the Russian Air Force retired its last Su-17M4 along with its fleet of MiG-23/27s in 1998. Angola The Soviets supplied the communist government of Angola with 12 Su-20Ms in 1982 or 1983, which formed the basis of the 15th FS. The squadron suffered a swift loss of at least six aircraft – most in mishaps – by 1985, and three more by 1988, and had only two aircraft left when it was reinforced with another Soviet batch of 14 Su-22M-4Ks and two Su-22UM-3Ks in 1989–90 (incorporated into the 26th Air Regiment, based in Moçâmedes). A second shipment from Belarus in 1999 consisted of two Su-22UBs and four Su-22Ms, and a third one from Slovakia in 1999–2001 consisted of 10 Su-22M-4s and one Su-22UM-3K. These aircraft saw heavy use in the war against UNITA. From the aforementioned losses, which can not be classified as mishaps or combat attrition, only an Su-20M, serialled C510 was reportedly downed in 1987 and a better-documented case occurred on 6 November 1994 when an Su-22 based at Catumbela was shot down by a surface-to-air missile launched by UNITA during a raid against Huambo. The pilot managed to eject and flee naked after stripping off his flight suit. Iraq From 22 September 1980 to 20 August 1988, during the Iran–Iraq War, Iraq used Su-17 export versions (Su-20 and Su-22) alongside older Su-7s. They were mostly used in ground-attack and close air support roles. Iranian Grumman F-14 Tomcats shot down 21 Su-20/-22s, that have been confirmed by western sources. Eighteen Su-20/-22s were also shot down by Iranian McDonnell Douglas F-4 Phantom IIs. and three by Iranian Northrop F-5s. On 20 October 1980 an Iraqi Su-20 shot down an Iranian F-4E with its 30 mm cannons. Official Iraqi accounts show no loss of Su-20 aircraft throughout