Airbus is urging Japan to base its next army utility helicopter on the X4, an advanced rotorcraft that the European manufacturer is developing for the civil market.

If the offer is accepted, the army UH-X program could be a breakthrough in Japan’s process of entering into the global arms market, since the military X4 would become a partly Japanese product offered for international sale.

Because Japan is now willing to consider arms exports, Airbus Helicopters and longtime partner Kawasaki Heavy Industries (KHI) do not have to consider the old, inefficient Japanese industrial practice of complete or near-complete license production of foreign aircraft at extremely slow rates. Instead, they have discussed the possibility of the Japanese company building the drive train and rotor for all X4s, says an industry official who is closely watching progress in the program.

Joint production would fulfill the Japanese defense ministry’s hopes that the army UH-X would support a civil export program. Conceivably, KHI could also do final assembly of X4s for the Asian civil market, especially since the company would probably need an assembly line for those delivered to the Japanese army.

The ministry intends to order about 150 army UH-X helicopters over 20 years. An unrelated Japanese navy helicopter program is also called UH-X.

A team comprising Bell and Fuji Heavy Industries (FHI) appears to be the other main contender for UH-X, probably offering a version of the Bell UH-1, such as the 412 or UH-1Y Viper. Sikorsky says its S-76D would suit the requirement, but industry officials say its only possible Japanese partner, Mitsubishi Heavy Industries, may not be interested.

Like Bell and Sikorsky, Airbus confirms its interest in the army UH-X program, but it does not name the aircraft it proposes as the basis for development. Its alternative offering was the EC155, but Airbus has suggested that helicopter for South Korea’s similar LCH-LAH program.

Choosing the X4 would raise risks for Japan, since the type is not even due to fly until 2015. But it would also simplify the allocation of manufacturing work, since Airbus cannot have decided yet on the production setup for the type. At this early stage in the program there should also still be opportunities to change the design to suit Japanese military requirements – at the risk of undermining civil competitiveness.

The Japanese army is worried by the risk that it would be forced to operate a basically civilian, and therefore not battleworthy, utility helicopter, an industry official says. The UH-1Y, used by the U.S. Marine Corps, would not present that problem, though it would also have a very small civil market, if any. The X4, UH-1Y and Bell 412 would all meet Japan’s requirement for two engines.

The defense ministry’s development budget for the army UH-X, ¥23-26.3 billion ($193-220 million), looks about right for developing a military version of the X4, industry officials say.

Armies sometimes need more powerful engines than civil operators do, because military versions of helicopters are fitted with more equipment, may have to carry heavier loads, and should have more maneuverability. Even substituting an engine with greater output than the X4’s currently planned Turbomeca TM800 and Pratt & Whitney Canada PW210, both of about 820 kW (1,100 hp.), may be possible within the Japanese budget, an industry official says. But Airbus is aiming at an unusually efficient drive and rotor system for the X4, so the type may be able to cope with a higher power loading than usual, that person says.

The weights of the X4 are unknown. Airbus refers to it as a successor to the AS365, which has a gross weight of just 4.3 metric tons in its current version, and the EC155, of 4.9 tons. But it is also aimed at competing with the highly successful AgustaWestland AW139, which, with a normal maximum weight of 6.4 tons, is in quite a different class. In an earlier phase of the UH-X program, Japan wanted a weight of about 5 tons, but the ministry declines to state its current specification to avoid prejudicing the competition.

The UH-1Y, able to fly at 8.4 tons, would be even further from Japan’s requirement. But the Bell 412, a civil derivative of the UH-1, has a gross weight of 5.4 tons. FHI built the UH-1Hs and UH-1Js that Japan is seeking to replace, adding to the industrial appeal of a Bell offering.

Indicating the power requirements for a modern battlefield utility helicopter in this class, the British army’s AgustaWestland AW159 Wildcat, of 6 tons gross weight, has two LHTEC CTS800 engines each with a maximum continuous output of 955 kW. Its power loading is therefore 3.1 kg per kW.

The ministry hopes to launch UH-X development by March 2016. Bidders are awaiting a request for proposals, but the ministry may first issue a request for comment, seeking guidance on how it should proceed.