Latest 737 Max Milestone Comes with Changes

 - November 15, 2012, 12:06 PM
Boeing 737 program vice president and general manager Beverly Wyse (Photo: Gregory Polek)

The Boeing 737 Max program has reached the development stage known as “firm concept,” following months of study into changes to the original design needed to effect a 13-percent operation cost improvement over the existing 737NG. During a Thursday morning conference call with reporters, 737 program vice president and general manager Beverly Wyse reported that the re-engining project remains on schedule for the completion of configuration details by the middle of next year and for first delivery in 2017.

Wyse explained that the milestone means that Boeing has defined the airplane’s configuration “in broad terms,” and that a firm plan remains in place to reach its fuel burn and maintenance cost goals. To get there, the company announced a change to its original plan to incorporate a bump in the bottom of the fuselage to accommodate the airplane’s longer landing gear and a switch to lighter, larger-format cockpit displays supplied by Rockwell Collins. The company also announced that Honeywell has agreed to supply the airplane’s electronic bleed air system.

Chief project engineer Michael Teal noted that the new four-display flight deck will not only improve visibility, it will also maintain operational and maintenance commonality with the system now used on the NG. “We continue to engage with regulators around the world about certification of the training plans for the MAX, but we feel these will not become an issue,” said Teal. Also expected to improve reliability and lower spares and maintenance costs, the new system will, perhaps most importantly, said Teal, lower upgrade costs over the life of the airplane. 

The other significant change announced on Thursday—the removal of the fuselage bump under the nose landing gear door—came about as a result of a modest redesign of what Teal called the kinematics of the door and the exclusive use of radial tires. Of course, Boeing had to lengthen the landing gear by eight inches to accommodate the wider diameter of the airplane’s new CFM Leap 1-B engines.

CFM froze the architecture of the new engines in September, meaning Boeing now knows the precise size of the fans and core and the number of stages. “The team is now working detailed design that will lead to engine design freeze in April of 2013, in advance of the airplane reaching its firm configuration milestone in mid-2013,” proclaimed Teal.

Expecting to flight test four 737 Max-8s and two each of the Max-7 and Max-9, Boeing has also cemented plans to build the flying prototypes and a third, so-called transition line in Renton, Washington, located adjacent to Line 1. Wyse said she expects the third line to start operation in 2015 as Boeing builds the flight-test articles, then use it for possible rate increases beyond the 42 a month now planned for the second quarter of 2014. Now building 35 Next Generation 737s per month in Renton, the company plans to raise that rate to 38 by next year’s second quarter before finally reaching 42 a year later.