The US Defense Department has chosen Australia and Japan to shoulder heavy airframe and engine maintenance for the Lockheed Martin F-35 Lightning II in the Asia-Pacific region beginning in 2018.

The two nations will split responsibility for heavy airframe maintenance, overhaul, repair and upgrade (MORU) in the Pacific, with Japan covering the north of the region and Australia the south, says Lt Gen Christopher Bogdan, head of the Pentagon’s F-35 joint programme office (JPO).

Australia also will take charge of maintaining the Pratt & Whitney F135 engine and establish the necessary infrastructure to perform tear-down, rebuild and test those owned by Asian programme partners and foreign military sales customers. Japan will begin to take on some additional engine overhaul work by 2023.

Light and medium maintenance refers to work that has no impact on the structure of the aircraft, Bogdan says. Heavy maintenance entails repairing large structural components like bulkheads, spars and wings, which require more advanced facilities and technical acumen.

While a number of factors went into the decision of where to assign the maintenance duties, geography played heavily in the Pacific, Bogdan says. Airframes are not easily transported long distance, which is why the work to maintain them was split between two nations. Engines can be broken down into modules, which are more easily transported to Australia from elsewhere in the Pacific, Bogdan says.

The distance between F-35 partners in the northern Pacific to Australia makes it prohibitively expensive and inefficient “to take airplanes from the northern Pacific that are getting ready to go into depot and fly them 7,000 miles”, Bogdan says.

“That requires significant tanking,” he says. “That requires a lot of alternate air bases and quite often some of those airplanes that have to be inducted into a depot are going in there because they need upgrades or there is something wrong.”

Still, it is unknown if political considerations would keep South Korea from having its jets serviced in Japan. Korea would have the option of having the work done in Australia, but Bogdan would not comment on the situation except to say that the JPO continually discusses “sovereign requirements” with each programme partner nation.

The partner nations’ industrial base is responsible for investment in infrastructure necessary to handle the regional workloads with the understanding that work will be doled out in sufficient quantity to make a return.

Based on the current footprint of F-35 in the region and the average interval expected for the engines and airframes to need depot-level maintenance, Italy’s airframe maintenance operation will receive an estimated 40 to 50 aircraft inductions between 2018 and 2022, Bogdan says. Those aircraft will require about 150,000h of work worth between $30 million and $35 million.

Japan, like Italy, has invested significant capital to build its own final assembly and checkout (FACO) facility where jets will eventually be built. Japan’s FACO, however, is being built with a vertically oriented production line that will use elevators to move jets through the assembly process, Bogdan says.