German and French officials are keen on transporting large pieces of equipment internally instead of relying on external slings. And the size of some of this equipment is driving a need for a larger cabin, raising the question of whether Europe is willing to go to a new design rather than off-the-shelf models.

Germany's head of army aviation, Brig. Gen. Reinhard Wolski, says this requirement was derived from lessons learned in Afghanistan. “Low flying at night, at high speed, is some kind of life insurance,” he told a heavy-lift helicopter transport panel at the ILA Berlin Air Show. “That puts quite an effort on [industry for] building the airframe as well as our cargo compartment.” Additionally, military customers are eager to purchase a helicopter that can still conduct missions with only one engine, another design stresser.

While such a large lifter—the notional target is an aircraft capable of carrying 32 metric tons of cargo—is desirable, it could be financially unattainable.

“Clearly, we could go build it,” says one industry official. “The question is: Does it make sense?” The Pentagon has also funded research to support a notional heavy-lift helicopter program, but a firm timeline and funding have been lacking.

Adding to the ambiguity about European requirements is an upcoming shift in the German military project management. The Luftwaffe is poised to assume oversight of the heavy-lift effort from the army on Jan. 1, 2013.

To keep their options on the table, Boeing and Eurocopter intend to continue work on their large tandem rotor-lifter concept, on view at the Berlin show as a beefed-up Chinook.

Boeing would bring its tandem-rotor technology to the project, while Eurocopter has extensive contacts in the French and German militaries, and could handle some parts and composites work.

Sikorsky also has design options that would include a platform larger than its CH-53K, which is now being developed by the Marine Corps.

However, both U.S.-based companies—Boeing and Sikorsky—also see an opportunity in offering off-the-shelf options that could reduce the cost for Europe to procure a system and, potentially, operate it.

Boeing, with EADS as a partner, could offer the CH-47F, which is now in production for the U.S. Army at the company's Philadelphia plant.