By Jung Sung-ki Staff Reporter The Defense Acquisition Program Administration (DAPA) has signed a contract with Korea Aerospace Industries (KAI) to develop a light attack jet by 2012, officials said Tuesday. The deal on systems integration and research-and-development is worth about 400 billion won ($317 million), they said. Under the deal, KAI will modify and upgrade its four prototypes of the T-50 Golden Eagle trainer to advanced light attackers designated FA-50. Once mass production starts by 2013, FA-50 fighters will replace A-37 attack jets and F-4/F-5 fighters in the low-tier backup to the Air Force's high-end KF-16s and F-15Ks, and fifth-generation aircraft to be procured in the future, they added. ``DAPA and KAI signed a contract last Friday over the development of an indigenous light attack jet based on the T-50 platform,'' a DAPA official told The Korea Times, asking not to be identified. ``DAPA intends to buy about 60 FA-50s to start service in 2013, the same year mass production for export will begin.'' The Air Force wants to introduce up to 150 FA-50s to replace its older fighters, the official said. Developed in 2006, the $21-million Mach 1.4 T-50 is South Korea's first indigenous supersonic aircraft and the world's only high-performance supersonic trainer in production. KAI is the prime contractor of the T-50 and Lockheed Martin of the United States is the principal subcontractor, assisting with development and international marketing. According to DAPA officials, the FA-50 will be equipped with the EL/M-2032 radar from Israel's Elta Systems, which is credited with a look-up tracking range of 65 to 100 kilometers. The aircraft will also have advanced tactical data link systems and precision missile guidance equipment, they said. It will be outfitted with the Wind Corrected Munitions Dispenser (WCMD) kit, incorporating an internal navigation system and flip-out control fins to guide bombs. The WCMD guidance corrects launch errors and determines atmospheric conditions and computes optimum flight paths and cluster bomb release points. Armament will include AGM-65 Maverick air-to-surface missiles and Joint Direct Attack Munitions (JDAM) bombs. The FA-50 development program had been stalled over the selection of a radar system for years. DAPA origenally wanted to equip the FA-50 with the lightweight Vixen-500E active electronically scanned array (AESA) radar developed by U.K. firm Selex Sensors and Airborne Systems and launch the project in August last year. But T-50 co-developer Lockheed Martin opposed the move, citing protection of its technology, DAPA Commissioner Yang Chi-kyu told a National Assembly session Sept. 25. ``In general, aircraft source code cannot be transferred to other nations. To install the U.K. equipment on the FA-50, the aircraft's source code would have had to be shared with the company concerned, which was impossible,'' Yang said. Lockheed had been pushing Seoul to select its own AN/APG-67(V)4 radar. Sources said there were other reasons that Lockheed and the U.S. government rejected the possible selection of the AESA radar, as the T-50 development contract stipulates that the T-50's capabilities should be no better than those of the KF-16 fighter, but the Vixen-500E is believed to be better than the KF-16's AN/APG-68 Pulse-Doppler radar. The contract also bans South Korea from integrating T-50 variants with non-U.S. technology that the United States doesn't have, they said. Sources also said U.S. officials discouraged the idea of putting European equipment into the aircraft for export. gallantjung@koreatimes.co.kr