Specifics about the evolving configuration remain closely held, and Boeing says it is still pursuing innovations across multiple areas—from manufacturing processes and production systems to propulsion—to help strengthen the business case. This twin-aisle-family concept is designed to fill the gap between the 737-10 and 787-8, and will seat 220-270 passengers and fly up to 5,000 nm.
However, while NMA is configured with a twin-aisle cross-section, it is targeted at single-aisle operating costs. To achieve this, Boeing is focusing on several advances in the overall design as well as on construction and propulsion.
But exactly how that will be accomplished remains proprietary information. “We have the process capability and the ability to architect and tool the airplane so that we can design the configuration we want in the production system we want. That’s about as deep as I’m going to go, because that’s part of the secret sauce,” says Mike Delaney, Boeing Commercial Airplanes vice president and general manager of airplane development.
Boeing's twinjet transition: chart
The NMA follows Boeing’s gradual evolution toward an all-twin passenger-jet family as the 747-8 becomes increasingly freighter focused. Credit: Boeing

Boeing is, however, making no secret of its increasing reliance on model-based systems engineering (MBSE) to dramatically change the way it is developing new products across the company. MBSE is an interdisciplinary approach that focuses on defining customer needs and functionality early in the development cycle. The concept, which is increasingly employed in its defense and space businesses, melds all disciplines and specialty groups into one cohesive team to pursue a structured development process that proceeds from concept to production to operation.
In Boeing’s case, the MBSE process comprises three types of engineering models—a systems architecture model feeds and interacts with analytic and verification models. The systems architecture model helps define the various constraints, interfaces and requirements around the development of the NMA’s design, as well helping to define the product itself. In particular, the systems model is being used to bound data management and control cost and schedule.
“NMA is a transformational program for the company. We have things we are doing around a ‘digital twin,’ which is an amazing enabler in terms of engineering,” says Delaney. Referring to MBSE, he adds that advanced system architecture models are already making the development process “completely different from the way we did the 787.” The new approach was used, for example, to develop the folding wingtip on the 777X. 
MBSE “significantly changes the nonrecurring formula in terms of time, engineering error, disruption in the factory, quality, flow and the things you have to work to change an airplane,” Delaney adds.
One unusual design feature to emerge using this approach is thought to be an unconventional cross-section that lacks the usual underfloor belly cargo space of aircraft such as the 767 and 787, but does dramatically reduce turn time. Although again declining to discuss specifics, Delaney says: “This airplane is really sized around the passenger.” He adds that Boeing has held talks with 57 airlines about the NMA. “The biggest thing people get excited about is opening new markets, and some of it is a new business model,” he says. “Some low-cost carriers want to grow up, some want to fill in their fleet, some want to [implement] disruptive things or restructure their networks.”
Another area of “secret sauce” in Boeing’s approach to the NMA is the closer-than-ever integration it is designing into the interface between the wing and engine. Discussions are ongoing with CFM (the General Electric-Safran joint venture), Rolls-Royce and Pratt & Whitney. “The only supply base we are talking to now is the three engine-makers because the engine-airframe is so highly integrated,” says Delaney.
NMA market space graphic
Boeing’s NMA is targeted at the middle-of-the-market gap between the 737 and 787. Credit: Boeing

“We go through a series of iterative processes with them, and what we tell them is designed to push the boundaries of the airplane. We tell people the takeoff-and-climb capability, the noise. We tell them things like an ETOPS ‘drift-down’ altitude [the maximum thrust required in the event of an engine failure in cruise when the aircraft cannot maintain altitude and terrain clearance is a factor], the ETOPS range circumference—all those things push the design. So the design is extremely fluid in their minds right now,” he adds.
Delaney says: “The engine companies are responding extremely well. We are very pleased with the technical interaction with all three.”