Boeing is speaking with potential customers and completing basic design work on a proposed 737 Max 10 airliner with an eye toward delivering a new member of the narrowbody series by 2020. Featuring a slightly longer fuselage and more passenger seats than the 737 Max 9, the Max 10 would compete against Airbus’s better-selling A321neo.

On March 6, Boeing briefed the Max 10 concept at the International Society of Transport Aircraft Trading (ISTAT) Americas conference in San Diego, where the idea met with some skepticism. In a teleconference with reporters on March 8, however, Boeing 737 Max program vice president and general manager Keith Leverkuhn said he is optimistic about the prospects for a fifth variant of the re-engined Max family.

“We’re talking to the customers,” Leverkuhn said. “Some of them were obviously saying we’ll take as many as we can get as early as we can get [them], and some are being more circumspect.”

With the program yet to be formally launched, Boeing is “well within our schedule” to complete a firm configuration of the basic 737 Max 10 design by next year, he said.

Though it would be just 66 inches (1.68 meters) longer than the Max 9—the first of which rolled out from Boeing’s Renton, Washington factory on March 7—the Max 10 would match the A321neo by seating 12 more passengers than its sister variant, or around 185 passengers in two-class configuration. The Max 10 also promises 5 percent lower per-seat and 5 percent lower per-trip operating costs with more range, Boeing contends. Airbus specifies a range of 4,256 nautical miles (6,850 km) for an A321neo equipped with Sharklet wingtips.

With the Max 10, “what we’ll do in order to keep as much commonality across the family as we can is we’ll just put more passengers on it and let the range fall off a little bit,” Leverkuhn said. “But the fact of the matter is that the 10X continues to have greater range than the competition. I’m frankly bullish on the airplane.”

Boeing is also studying concepts for a landing gear extension that is needed for the longer aircraft; among them creating linkages at the top of the retract actuator to allow the additional length of gear to fold into itself, Leverkuhn said.