Rolls-Royce has submitted its UltraFan engine to power Boeing's New Mid-market Aircraft (NMA), sources close to the matter told AIN at the Farnborough Airshow. The British engine maker's chief executive, Warren East, told reporters Tuesday that the company had submitted proposals to Boeing. "They’ll continue to refine their requirements, and we’ll continue to see if we can address those requirements economically,” he said.

East did not specify which engine designs Rolls-Royce submitted at the briefing. Asked if the submissions included the UltraFan, a Rolls-Royce spokesman declined to comment.

Competitor CFM International has bid its CFM Leap for the airplane, whose thrust requirements might strain the engine's upper thrust range.

Boeing asked engine makers to submit proposals earlier this month, but the Seattle airframer has given itself until the end of next year to decide on whether to proceed with or shelve the NMA. Many industry analysts question whether Boeing can actually make the business case for a twin-aisle jet with single-aisle economics. The NMA would fit between 220 and 260 passengers.

Boeing aims targets the NMA's service entry in 2025, the same year Rolls-Royce plans to ready its UltraFan for service. It expects to start ground testing in 2021.