Soko J - 1 Jastreb The Soko J - 1 Jastreb , aka J - 21 Jastreb is a Yugoslavian turbojet fighter - bomber aircraft , with a secondary capability as a low - level interceptor , designed by the Aeronautical Technical Institute ( ATI ) , ( ( VTI ) ) , in Belgrade and manufactured by SOKO . Derived from the G - 2 Galeb advanced jet trainer and light attack aircraft , it was designed in single - seat ground - attack and two - seat advanced flying / weapon training versions . Design and development . The J - 1 Jastreb was developed as a replacement for the Republic F - 84 Thunderjet , which had been the most commonly used turbojet fighter - bomber aircraft of the Yugoslav Air Force until 1967 . On the basis of the G - 2 Galeb , the J - 1 Jastreb was developed as a single seat ground attack variant , flying for the first time on 19 July 1965 . Pilots sit on licence - built Folland Type 1 - B ejection seats under individual canopies hinged on the starboard side in un - pressuried cockpits . Instruments and controls are entirely conventional with manually operated flying controls and standard flight instruments . Powered by a single BWB licence - built Rolls - Royce Viper Mk531 the Jastreb has a conventional Aluminium Alloy stressed skin structure with few or no special features . The relatively thick aerofoil section , though limiting performance , provides room for fuel cells and the retracted main undercarriage which retracts inwards , giving the Jastreb a wide track and imbuing it with excellent ground handling characteristics . The levered undercarriage legs and relatively low pressure tyres allow the Jastreb to operate from un - prepared strips or rough surfaced airfields . Compared to the Galeb , the Jastreb has a strengthened structure , allowing more weapons to be carried , including three Browning AN / M3 machine guns with 135 rpg , mounted in the nose of the aircraft . As well as the nose - mounted guns , the Jastreb is able to carry up to on under - wing pylons , two inner pylons having a capacity of for bombs , rocket launchers and additional tanks , while the six outer pylons can carry VRZ - 157 rockets . Operational history . The J - 1 enterred service with the JRV ( Yugoslavian Air Force ) on 31 December 1968 , with very few , if any , remaining in service . First Congo War . According to some reports , France and Yugoslavia supported Mobutu ' s government during the First Congo War . Namely , Yugoslavia agreed to deliver three J - 1 and a single G - 2 aircraft , as well as four MiG - 21 PFMs , while three Mi - 24 s were purchased from Ukraine . All these aircraft were based at Gbadolite and flown mainly by Serbian mercenaries . With few exceptions it remains unknown exactly what happened with each of these aircraft and how they were used after their arrival in Zaire , in late 1996 - 1997 . In the case of Mi - 24s it is known that one hit a power line and crashed on 27 March 1997 , killing the three crewmen and four passengers . The fate of at least one J - 1 Jastreb was not much better : one of the Serbian pilots , Ratko Turčinović , was killed while flying an ultra - low - level pass over Gbadolite , clipping a lamp post with his wing . The wreckage of his aircraft fell directly into a column of young soldiers on a parade , killing dozens . The accident is reported as being attributed to Turčinović ' s alcohol dependency . Soon after the accident , the Serbs were expelled from the DRC and the Jastrebs were abandoned along with the Galebs . MiG - 21s and Mi - 24s , which were awaiting assembly by Russia n or Ukrainian technicians at Gbadolite , were also abandoned and can still be seen on the ramp at Gbadolite ( 2013 ) .