If there is one misconception about South Korea's F-X Phase 3 fighter competition, due to be decided this month, it is that the requirement is aimed mainly at bolstering defense against North Korea. On the contrary, say senior government officials in Seoul, at least as strong a reason for buying 60 advanced fighters is South Korea's perceived strategic competition with Japan, China and Russia—probably in that order.

“Our neighbors are upgrading their fighter technology, so we must do so, too,” says one government official. A second official, with deep insight into the country's defense requirements, goes further: The 60 Boeing F-15Ks that South Korea has from the F-X Phase 1 and 2 programs last decade already offer enough aerial strike power for dealing with North Korea. While more big fighters would be useful if war on the peninsula broke out, the real point of the Phase 3 competition is that Japan is buying Lockheed Martin F-35As, China is developing the J-20, and Russia is working on the Sukhoi T-50 (PAK FA), says that official. Even in F-X Phases 1 and 2, North Korea was considered only part of the problem, he adds.

That is why South Korea's Defense Acquisition Program Agency is giving equal importance to air-to-air and strike missions in F-X Phase 3, even though defeating North Korea's modest fighter force would hardly be a challenge. Slightly contradicting that, an F-X Phase 3 program official told Aviation Week two years ago that excellent strike capability was valued above excellent air-to-air capability. Still, the difference in weight given to the two capabilities is evidently not great.

It is not known whether North Korean bellicosity this year has changed F-X Phase 3 priorities, but Pyongyang's aggression has probably helped the two U.S. contenders—the F-35A and F-15SE—in competing against the Eurofighter Typhoon. The argument is simply that the U.S. contributes greatly to the defense of South Korea, which should partly repay the favor by giving its largest defense import contracts to U.S. suppliers, especially when, as in this case, it has at least two to chose from.

At least until North Korea made blood-curdling threats recently, reminding everyone of the importance of U.S. backing for South Korea, one view was that, although Seoul should generally place such a big order with the U.S., it could make an exception. “Just this once” it could import a non-U.S. fighter, above all because Eurofighter could offer greater technical help for the proposed indigenous KF-X program. Bids for F-X Phase 3 will be judged partly on prospective contributions to KF-X.

But South Korea is not sure it wants to build the KF-X. What if a supplier wins F-X Phase 3 with a generous technology transfer package, and then never has to transfer the technology? That, in the view of some South Korean aerospace officials, is a key fault in the import competition. All of the bidders are offering fighter technology, with the Eurofighter consortium unconstrained by U.S. government regulations. Going further, Eurofighter shareholder EADS is offering to invest $2 billion in the program if South Korea buys the Typhoon. And that only deepens the F-X contradiction: If EADS won and KF-X died, the obligation to invest would die with it. For that reason, the importance of offers to help develop the KF-X is questionable. The indigenous fighter is encountering strong domestic opposition, criticized as unaffordable or unviable (AW&ST April 29, p. 49).

The EADS offer further includes an aircraft maintenance facility and an aerospace software center, says Yonhap news agency. South Korea could build, or at least assemble, most of its Typhoons, say industry officials. The U.S. bidders are also offering industrial benefits (AW&ST April 15, p. 52). Korea Aerospace Industries (KAI), already building major assemblies of the F-15, could step up its involvement in that program, while for the F-35 the industry would receive advanced manufacturing work on a project with a long prospective production life. Crucially, South Korean F-35As would not rely on a Japanese maintenance base, says an industry official. Lockheed Martin's offer of technology transfer had better match what the company has given Japan, says a government official. “South Korea won't put up with second-best anymore,” he says.

As part of its offset deal, Lockheed Martin may have offered to buy two KAI T-50 trainers (unrelated to the Sukhoi T-50) in support of its bid for the U.S. Air Force's T-X program, South Korean officials say. In the opinion of some, the best offset deal that EADS could offer would be a Spanish order for 20 KAI T-50s. EADS's proposal to invest in KF-X suggests that the idea will not be taken up.

The Typhoon, designed less for air-to-ground than the U.S. aircraft, is a viable bidder because air-to-air is important. Like the F-15SE and F-35, it meets a key range requirement to maintain a patrol over the Liancourt Rocks, islets whose ownership is disputed by South Korea and Japan. That requirement underlines the importance of perceived threats other than North Korea. The radar signature of the Typhoon is low enough for South Korea's purposes, says a local official, pointing out that it is Britain's premier fighter. “That aircraft is the leading fighter of the Royal Air Force, which is one of the most advanced air forces in the world,” he says. “It is good enough for us.”

This official does not specifically recommend the type but also notes that the Typhoon is a ready design, whereas the F-35A remains in a protracted development program and the F-15SE, an upgrade of the F-15 whose features are intended to control radar reflections, also needs considerable engineering work—though some of that work would be welcomed by South Korean industry. Technical maturity of the F-15K was a key reason for choosing it for the Phase 1 and 2 orders.

To some extent, the relative competitiveness of the F-15SE and F-35A depends on exactly what strike missions South Korea has in mind. At the outset of a war with North Korea, it is unlikely that any aircraft would fly far into North Korea, demanding all-aspect stealth, says an industry official. Rather, the priority would be attacking North Korean forces close to the front, especially artillery that would by then be raining destruction on Seoul. South Korean fighters, especially the heavy fighters bought under the F-X orders, would repeatedly sprint northward toward the front, pulling up well before it to toss guided bombs beyond the line. The bombs would reverse course to hit artillery emplaced on the far side of the mountains north of Seoul.

For that mission, sheer thrust and bomb-trucking capacity would be key, and the big F-15SE would offer the most among the three contenders. Despite the air-to-ground strengths of its design, the F-35A would be somewhat disadvantaged, especially early in its service life, when it would be unavailable with external ordnance. The F-35A would surely be the aircraft of choice for deep-penetration missions, but South Korea has bought the German-Swedish Taurus air-to-surface cruise missile and is fielding a wide variety of indigenous surface-to-surface cruise and ballistic missiles (AW&ST May 21, 2012, p. 27). None of those weapons has any known ability to deal with moving targets, notably transporter-erector-launchers for ballistic missiles. But it seems doubtful that even F-35As would be tasked with loitering over North Korea, awaiting detection of such targets, until after the enemy air-defense system was shut down. Yet if it had to be done, South Korea would want a stealth fighter to do it.

The importance of those considerations depends on the prominence of the North Korean threat in F-X Phase 3. To the extent that South Korea is worried more about Japan, the F-35A is strongly placed in the competition. A simple example illustrates why: It would be intolerable to South Koreans to hear that their F-15SEs or Typhoons while patrolling near the Liancourt Rocks had been bounced by Japanese F-35As that they had failed to detect. The age of the F-15 basic design is also noted in South Korea. It first flew in 1972 but would be expected to serve in the country until about 2060. South Korea's big old F-4 Phantoms, among the aircraft that the F-X Phase 3 fighters will replace, will leave service about 60 years after that type's first flight.

A mark against the F-35A is that it is probably the most costly of the three types on offer, yet it is also the one that the air force most wants, officials say. The government is budgeting 8.3 trillion won ($7.3 billion) for F-X Phase 3; one official believes the cost could easily rise to 10 trillion won. Indeed, Lockheed Martin says its aircraft is $10.8 billion. The F-15SE would surely be the cheapest choice, since South Korea has the support infrastructure for the F-15Ks. A reasonable approach might be to buy it for only 20 years of service, so it did not have to fly until around the 90th birthday of its design, but officials say no such policy is being considered.

With Bill Sweetman in Washington.