In English-speaking countries, people like to keep up with the Joneses. For South Korean defense ministry officials, it is important to keep up with the Tanakas.

That is one reason why Japan's expected order for the Lockheed Martin F-35 is likely to result in sales of more than the 42 fighters that industry officials anticipated Tokyo would buy. Another is that the aircraft chosen for Japan's fighter program for this decade may well be built throughout the 2020s, long after the initial requirement is filled.

A Japanese order for F-35s, especially if followed promptly by one from South Korea, will bolster early demand for the stealth fighter, potentially offsetting reductions in purchases by other customers, such as the U.S. and cash-strapped European countries. Both North Asian countries urgently need to replace old F-4 Phantoms—and, with the F-35, both would run the risk that the troubled program could force them to wait longer than planned.

Japan's decision, leaked to leading local media and expected to be announced before the end of the year, is also likely to confirm that Japan has drawn a line under its 55 years of full-scale fighter manufacturing. With the F-35, Japan is likely to join Italy in assembling the aircraft, but industry officials say the need to protect stealth secrets means that the F-35 cannot be completely manufactured outside of the U.S.—and doing so would be extraordinarily costly anyway.

Boeing and Eurofighter, offering the F/A-18E/F Super Hornet and Typhoon, respectively, have been Lockheed Martin's rivals in Japan's F-X competition. Their aircraft have been available for extensive manufacturing in Japan.

The same two companies now stand at heightened risk of losing the similar but larger competition to supply 60 fighters to South Korea. One issue on the minds of the competitors is that South Korean defense ministry officials would be loath to buy an aircraft that the country's highly nationalistic politicians and voters would criticize as less modern than Japan's. The F-35 looks like a safer buy—even though, in both countries, critics will likely question the wisdom of choosing the immature design, especially after the latest revelations of development troubles in the leaked “quick look review” report (see p. 30).

A U.S. defense official says no changes are being made to the F-35 development schedule as a result of the report. These issues were known to the program office and contractor, and fixes are being worked on.

In South Korea, Boeing is offering the F-15SE Silent Eagle, derived from the F-15K, which is already partly built there. Again, the Silent Eagle and the Typhoon promise to sustain South Korea's domestic fighter production base, whereas the F-35 would leave plants, engineers and mechanics looking for other work.

Japanese industry has urged that the new fighter chosen be built until the late 2020s. Even at the low production rates typical in Japan, that would result in deliveries of perhaps 120 fighters, partly replacing Japan's Boeing F-15J Eagles. Under the i3 program, Japan is working on technologies for another fighter that would be built starting in the 2030s.

Reasons for Japan's F-35 choice include its stealth and suitability for information-networking, says the Yomiuri newspaper, adding that the Japanese government is satisfied with U.S. willingness to share information with Japanese manufacturers. It is taboo in Japan to discuss strike missions, but another key advantage of the F-35 is clearly its ability to penetrate hostile defenses, notably those of North Korea. The F-4s are tasked with air-to-air missions, but Lockheed Martin promotes the F-35's air-to-ground capability.

The order for the first four aircraft, fully imported, should be in the budget for the year beginning April 1, 2012, with deliveries starting in 2016. Japanese companies will help make later units. Unless Japan relaxes its ban on arms exports, it cannot supply parts for F-35s built for other countries—although the desire to sustain the industry and hold down costs could lead to a change in policy. Japan launched a review of the ban last year, possibly in anticipation of an F-35 order.

In the run-up to the decision, Lockheed Martin bolstered its bid by offering Japan manufacture of several F-35 components as well as final assembly and checkout, integration and test, depot-level sustainment, repair and overhaul. The assembly plant will cost about $1 billion, industry officials say. Japan will also be able to assemble the F-35's Pratt & Whitney F135 engine, although any customer will need to do that if it is to overhaul the turbofan.

The Japanese air force originally hoped to replace its last Phantoms in the fiscal year beginning in April 2009 and lobbied the U.S. to be allowed to buy the Lockheed Martin F-22. The replacement program slipped even as Mitsubishi Heavy Industries and suppliers such as IHI Corp. and Mitsubishi Electric Corp. faced the end of F-2 strike fighter production. The last F-2 was handed over in September.

The manufacturers proposed building more F-2s to keep themselves busy, but in the past few weeks it has become more clear why that was not a possibility. Defense Minister Yasuo Ichikawa told the Diet on Nov. 9 that more F-2s would cost ¥15 billion ($193 million) each. The F-2, based on but larger than the Lockheed Martin F-16, has also been criticized as too small for further development.

The Japanese order, and its potential South Korean follow-on, have unusual value to the program because the two countries and the manufacturer are all keen on early deliveries. Lockheed Martin hopes for more units in early batches to reduce unit costs, says Tom Burbage, executive vice president of F-35 integration at Lockheed Martin. Equally important, he says, is stability. “We have not yet had a year where the number we planned is what we got appropriated,” causing turbulence in the supply chain, he says. “Facing volatility in our supply chain is one of our biggest challenges.”

For Japan, the challenge will be to receive new aircraft on time to preserve its fighter force. To begin taking delivery in 2016, its first aircraft will be part of the low-rate initial production batch 8 (LRIP 8), which is due to be ordered in 2014. The 2016 deliveries are scheduled to include the Block 3 software.

The South Korean defense ministry also hopes to order next year and begin taking delivery in 2016, a schedule that seems uncomfortably close to the JSF development plan. The program's technical baseline review conducted this year called for testing to finish in 2016 on the F-35A, the version that the North Asian countries are interested in. The F-35 program—the Joint Program Office and Lockheed Martin—recently wrapped up an integrated baseline review that is intended to match funding to work laid out in the technical baseline review.

Comments by the chairman of the U.S. Joint Chiefs of Staff, Army Gen. Martin Dempsey, last week hinted that there may be slips in F-35 orders; the details will appear with the budget release in February. Meanwhile, the Defense Acquisition Board will review the integrated baseline plan and new cost estimates for the program next month.

The Joint Executive Steering Board (JESB), a panel of senior officials from each F-35 country, was supposed to have its second 2011 meeting this month. But the meeting has been delayed to March because the U.S. government might change its planned orders in February. The JESB should include obligations for LRIP 6, but any slips would likely ripple into later LRIP buys, including LRIP 8.

While the plans of the U.S. and other customers are not solid, more than 100 F-35s are in the LRIP 8 buy, customers for which include the U.S., Italy, Australia, Netherlands, Norway, Israel and Turkey.

In contrast to the program boost from the urgency of Japanese and South Korean requirements, Australia's long-standing commitment may be in doubt because Canberra cannot afford to wait beyond the end of the decade to replace its Boeing F/A-18A/B Hornets. It has already begun buying the obvious F-35 alternative, the Super Hornet.

With Bill Sweetman in Washington.