South Korea is spending several hundred million dollars to upgrade most (96 percent of) their 140 KF-16 fighters. These were assembled in South Korea from 1994 to 2004 under license and are going through a mid-life upgrade in the United States. This will involves installing a more powerful AESA radar, new electronics (displays, sensors and computers) as well as new cabling and other related components f0r 134 KF-16s. The upgrades will begin in 2014 and the first completed aircraft will be ready by 2019. Because not all the new features have been decided on yet the exact price is not yet known but will be at least $4 million per aircraft. The most time consuming aspect will be removing and replacing much of the cabling. The interior of an F-16 is a very crowded place and it’s a tedious effort getting in there to do major upgrades.
The AESA (Active Electronically Scanned Array) radars are becoming standard equipment in modern warplanes. AESA is more reliable and, increasingly, no more expensive than the older mechanical (a small dish that moves around inside a dome) radar. AESA is also easier and cheaper to maintain, which makes a more expensive AESA cheaper, over its lifetime, than a cheaper (to buy) mechanically scanned radar. AESA type radars have been around a long time, popular mainly for their ability deal with lots of targets simultaneously, and produce a more accurate picture of what is out there. AESA radar consists of thousands of tiny radars that can be independently aimed in different directions. An AESA radar made the U.S. E-8 JSTARS aircraft possible, as it enabled it to locate vehicles moving on the ground. An innovative and much smaller MP-RTIP AESA radar for the RQ-4 Global Hawk UAV can also spot smaller objects on the ground. Alas this AESA radar is used at high altitude (over 10 kilometers/31,000 feet), too far for a high-energy (electronics destroying) signal. But other UAVs, like Reaper, are cheaper and fly lower, low enough to zap ground targets with the electronics-destroying beam. For heavily defended or very distant targets the cruise missile approach, while more expensive, would get the job done. While AESA makes fighters much more effective, it's the many other uses of AESA that make this technology so attractive to warplane designers. For example, the U.S. Air Force has been equipping some of its fighters with the ability to focus the high-powered microwave (HPM) effects found in AESA radar technology. AESA is able to focus a concentrated beam of radio energy that can damage electronic components of a distant target. The air force won’t, for obvious reasons, discuss the exact “kill range” of the various models of AESA radars on American warplanes (the F-35 and F-22 have the most powerful ones). However, it is known that “range” in this case is an elastic thing. Depending on how well the target electronics are hardened against EMP, more electrical power will be required to do damage. Moreover, the electrical power of the various AESA radars in service varies as well. The air force has said that the larger AESA radars it is developing would be able to zap cruise missile guidance systems up to 180 kilometers away.
The U.S. F-16 is one of the most modified jet fighters in service. While most are still called the F-16C, there are actually six major mods, identified by block number (32, 40, 42, 50, 52, 60), plus the Israeli F-16I, which is a major modification of the Block 52. The F-16D is a two seat trainer version of F-16Cs. The various block mods included a large variety of new components (five engines, four sets of avionics, five generations of electronic warfare gear, five radars and many other mechanical, software, cockpit and electrical mods.)
Meanwhile South Korea and Indonesia agreed in 2010 to jointly develop a new fighter, the KFX. This would be an aircraft with capabilities somewhat beyond the top-line American F-16 Block 60. The best example of this is a special version of the Block 60 developed for the UAE (United Arab Emirates). The UAE bought 80 "Desert Falcons" (the F-16E) which is optimized for air combat. It is a 22 ton aircraft based on the Block 52 model (which the KF-16 was originally), but with an AESA (phased array) radar and lots of other additional goodies (what the upgraded KF-16 will largely be).
KFX development is expected to take ten years and cost $2 billion. South Korea hopes to build on the work it did to develop its T-50 jet trainer. This is a 13 ton, two seat, single engine aircraft that is also available as a combat model (the F-50), which carries a 20mm autocannon and up to three tons of bombs and missiles. The KFX would weigh twice as much, have one or two engines, a single seat and the ability to carry twice as much weight in weapons. The KFX is expected to look more like the Eurofighter Typhoon, than the T-50 or F-16. The KFX is also expected to cost $50 million each, have advanced electronics (including an AESA radar). Indonesia will provide 20 percent of the development costs and buy fifty of the KFX’s. South Korea will buy 150-250 of the new aircraft, to replace its current fleet of elderly American F-4s and F-5s. This is an ambitious undertaking, and success is not certain, especially when the timeline, budget and aircraft performance are concerned. The KFX is still officially in the works but is delayed for the moment over political opposition to the escalating costs. KFX may be cancelled if another aircraft (like the French Rafale or the multinational Eurofighter) are offered with equivalent capabilities and a lower price. That is where this is headed at the moment.