Photo/IllutrationThe Asahi Shimbun

Maintenance costs for U.S.-made military aircraft are expected to balloon at such a rapid pace that some officials fear the expenses will end up hurting Japan’s security capabilities.

Defense Ministry officials have tried to find ways to reduce the spending, but no feasible ideas have been brought forward, except for the possible development of Japan’s own arms industry.

Concerns are rising that the costs paid to the United States to buy and maintain state-of-the-art aircraft will deplete the budget to service existing naval vessels and military vehicles.

“Maintenance funds for other helicopters and small planes will be reduced, making it impossible to repair them or replace their parts,” a senior official of the Self-Defense Forces said. “That could result in a decreased operational rate of SDF units.”

Japan now plans to introduce four types of the most advanced U.S.-made aircraft: Osprey transport aircraft, F-35 stealth fighters, Global Hawk unmanned surveillance aircraft, and E-2D early warning aircraft.

The total annual average maintenance cost for these aircraft is estimated at 86 billion yen ($772 million) over 20 to 30 years.

Tokyo has a number of ways to buy aircraft and other military equipment from the United States, including imports through trading companies and via Washington’s government-to-government foreign military sales (FMS) program.

After President Barack Obama took office, Washington emphasized FMS to prevent its military-related technologies from being leaked or its weapons resold to terror groups.

Most of the state-of-the-art weaponry, including the F-35s, Ospreys and Global Hawks, that Prime Minister Shinzo Abe’s administration is eyeing are to be procured through FMS.

FMS-bought weapons require higher maintenance costs than those developed by Japanese companies.

Japan’s spending through FMS procurement was 43.1 billion yen in fiscal 2011. The figure surged tenfold to 470.5 billion yen in fiscal 2015, and 485.8 billion yen was earmarked for fiscal 2016, putting an additional strain on Tokyo’s defense budget.

Arms purchased through FMS are repaired and maintained by the U.S. side until the weapons are finally scrapped.

The Defense Ministry estimates that 460 billion yen, or an average of 23 billion yen a year, will be needed over 20 years to service the 17 Ospreys for the Ground SDF, on top of the purchasing cost of 184.2 billion yen.

The 42 F-35 fighters that Japan plans to buy are estimated to require maintenance expenses of 1.2 trillion yen over the 30-year period, or an annual average of 40 billion yen.

Around 1 trillion yen of Tokyo’s total defense budget has recently been used to buy equipment produced both in Japan and abroad, while about 800 billion yen is used annually for maintenance.

But the maintenance costs are rising because the high-performance weaponry has become even more sophisticated.

Japan’s maintenance expenses totaled less than 500 billion yen in the 1990s but had nearly doubled to 867.1 billion yen by fiscal 2016.

The Defense Ministry has tried to reduce the servicing costs by conducting periodic repairs less frequently and reviewing its contracts with arms companies.

However, the maintenance expenses are expected to further increase with the FMS-purchased aircraft and other weapons.

Nearly half of the GSDF’s maintenance money for aircraft will be used only for the 17 Ospreys, according to SDF sources.

The GSDF had 390 aircraft as of March 2016.

Although the Defense Ministry has considered countermeasures, a ministry executive said, “No good ideas have been proposed.”

Another senior ministry official involved in the FMS procurement said Tokyo has no choice but to make low-key efforts.

“We can only heighten negotiations with Washington to reduce servicing costs and lower expenses associated with domestically made weapons,” the official said.

Heigo Sato, a national security professor at Takushoku University, said Japan’s inability to produce high-performance arms is a major reason why the amount through FMS has surged.

“It is difficult to persuade the U.S. government to lower maintenance costs,” Sato said. “Tokyo simply has to increase the defense budget and rein in costs as part of its short-term strategy and urge Japanese companies to develop high-performance weapons or to participate in international joint arms production projects in the medium- and long-term perspective.”