Su-24M ('Fencer-D')
Work on upgrading the Su-24 was started in 1971, and included the addition of inflight refueling and expansion of attack capabilities with even more payload options. T-6M-8 prototype first flew on 29 June 1977, and the first production Su-24M flew on 20 June 1979. The aircraft was accepted into service in 1983. Su-24M has a 0.76 m (30 in) longer fuselage section forward of the cockpit, adding a retractable refueling probe, and a reshaped, shorter radome for the attack radar. It can be identified by the single nose probe in place of the three-part probe of earlier aircraft. A new PNS-24M inertial navigation system and digital computer were also added. A Kaira-24 laser designator/TV-optical quantum system (similar to the American Pave Tack) was fitted in a bulge in the port side of the lower fuselage, as well as Tekon track and search system (in pod), for compatibility with guided weapons, including 500 and 1,500kg laser-guided bombs and TV-guided bombs, and laser/TV-guided missiles Kh-25 and Kh-29L/T, anti-radar missiles Kh-58 and Kh-14 (AS-12 'Kegler') and Kh-59 (AS-13 'Kingbolt')/Kh-59M TV-target seeker guided missiles.[1] The new systems led to a reduction in internal fuel amounting to 85 l (22.4 US gal). Su-24M was manufactured in 1981–1993.[1]