South Korea is having a problem with the ALQ-135M self-protection jammer that is built into their F-15K fighter bombers (similar to the U.S. Air Force F-15E), rather than carried as a pod. Seven percent of the ALQ-135M systems have proved very unreliable and all the others require a lot of maintenance. Since the ALQ-135M for the F-15K was a custom installation, it's difficult to get spare parts. Thus South Korea has agreed to buy six more ALQ-135M sets (uninstalled) for use as spares.
Maintenance costs for the F-15K in general have been growing sharply in the last four years. In addition, South Korea has not been happy with the quality of the $100 million F-15K fighter bombers they are buying from the U.S. Boeing firm. Two years ago an F-15K arrived with several defects, all attributable to poor quality control. This was nothing new. Four years ago South Korean Air Force officials had a "good news/bad news" message for Boeing, regarding defective components in the 29 F-15K fighter-bombers that were recently delivered. Some 1200 components were found to be defective. This did not create any serious operational problems with the aircraft. The South Koreans also pointed out that each aircraft had 65,000 components that might need to be repaired or replaced, which meant the 1,200 defective parts represented only one part in every 1,667. Boeing and the U.S. Department of Defense assured South Korea that quality inspections, by Department of Defense inspectors, would deal with the problem. They did, for a while. But later it was found that some of the inspectors were unqualified or not assigned to where they were most needed. Although the F-15Ks are assembled in the United States, many of the components come from South Korean firms.
Doubts about Boeing quality control goes back to 2005, when one of their F-15Ks was lost in an accident. That incident turned out to have resulted from the pilot turning too sharply and blacking out from excessive G-forces. Despite the 2008 problems, South Korea went ahead and ordered another 21 F-15Ks.
The F-15K is a customized version of the 36 ton U.S. F-15E (a two seat fighter bomber version of the single seat, 31 ton F-15C fighter). Already in service for over twenty years, the F-15E can carry up to 11 tons of bombs and missiles (compared to 8 tons on the F-4s South Korea was previously using as a fighter-bomber), along with a targeting pod and an internal 20mm cannon. It's an all-weather aircraft that can fly one-way up to 3,900 kilometers. It uses in-flight refueling to hit targets anywhere on the planet. Smart bombs made the F-15 particularly efficient. The backseater handles the electronics and bombing. The F-15E remains a potent air-superiority fighter, making it an exceptional combat aircraft. This success prompted Israel, Saudi Arabia, South Korea, and Singapore to buy it, paying about $100 million per aircraft. In the U.S. Air Force the F-15E is one of the most popular aircraft for combat pilots to fly, even more so than the new F-22.
These quality issues are making some potential buyers nervous. Quality control has long been a problem with American defense manufacturers and some projects were terminated because neither the manufacturer nor the military service buying the item could cope with poor quality control. The South Koreans have learned that the only solution is to apply lots of pain to the offending suppliers, which seems to be working. But a good supplier can suddenly go bad and you have to be ready to apply the heat again.