Boeing will officially launch the 737-10 on the first day of the Paris Air Show, marking the go-ahead of the fourth major member and fifth derivative of the MAX family.

Featuring an additional 66-inch fuselage stretch over the 737-9 as well as modified main landing gear, the 737-10 is a response to the Airbus A321neo and will extend single class seating capacity to 230. The aircraft will enter service in 2020 following the debut of the 737-9 in 2018, and the entry-into-service of both the 737-7 and 200-seat MAX 200 in 2019.

Though details of the launch customers were yet to be released as Show News closed for press, the initial orderbook is expected to be in the 100-plus aircraft range. The first group of orders is expected from lessor China Aircraft Leasing Group Holdings, as well as Indonesian-based low-cost carrier Lion Air. Indian airline Spice Jet is also expected to be among the launch group. Boeing is also understood to be in talks with European carrier Ryanair over the 737-10, though it is not known if these have been finalized in time for any announcement at the show.

Boeing Commercial Airplanes president and CEO Kevin McAllister says, “the airplane looks great. We have a lot of customers very interested.” Speaking on the eve of the show, McAllister says “customers told us they wanted it bigger and this airplane offers the opportunity for up to 230 seats. But they want it better. The opportunity to offer the extra seats but also maintain the cost per seat-mile advantage and trip costs of the MAX family was very important for our customers.”

The additional stretch takes overall length to 143 ft. and increasing two-class capacity to 189 passengers, compared to 193 for its arch-rival the Airbus A321neo.  The fuselage extension also means Boeing has to incorporate a modified main landing gear design to enable adequate clearance of the longer body for rotation on take-off and landing, and to ensure the aircraft remains stall – rather than pitch – limited. The MAX already incorporates an 8-in. nose leg extension to increase ground clearance for the larger diameter CFM Leap-1B, and is still reviewing final options for the -10 main gear changes.