Boeing unveiled the first 737 Max 8 flight test aircraft on 8 December in a low-key employee- and supplier-only ceremony scheduled 19 years after the 737-700 roll-out and nearly 49 years after a champagne-soaked christening of the original 737-100.

The absence of public fanfare reflects a decision to focus the event on an internal audience, congratulating employees and suppliers who so far have kept the re-enginging programme on time, says Keith Leverkuhn, Boeing vice-president and general manager for the 737.

Boeing even kept the aircraft’s official “roll-out” – when the 737 Max 8 moved from final assembly to a nearby paint hangar – a secret when it was completed on time on 30 November, Leverkuhn says.

“We wanted to thank our employees and our team,” Leverkuhn says. “All the milestones have been met. Engineering has been early. The supply chain is performing well. When the airplane actually showed up here in the factory, the mechanics were ready to go. The parts teams were ready to go. So this is a celebration for the team.”

The public unveiling of the freshly painted 737-8 in a unique teal livery marks a shift in focus for the four-year-old programme. Since completing the detailed design process a year ago, the focus has been on releasing parts to suppliers and assembling the first group of test aircraft.

737 Max rollout 640

Jeremy Dwyer-Lindgren.

The first aircraft – dubbed “1A001”, after the 787 programme retired the alphabetic prefix with “ZA001” – now enters pre-flight testing, as the remaining three test aircraft continue assembly.

1A002 is nearing the final stages of final assembly, with the fuselage and wings mated and systems installed. Boeing machinists swung the landing gear – sized 20cm (8in) longer to accommodate the 69.4in fan diameter of the CFM International Leap-1B engines – for the first time on 7 November.

A tour inside 1A002 on the assembly line revealed a completed cockpit and a fuselage filled with partially completed test stations. No water ballast tanks used were visible, suggesting 1A002 will be dedicated for testing the 737 Max’s new avionics and electrical systems.

The redesigned tail cone for the 737 Max in final assembly presented a striking visual contrast with the aft fuselage of 737NGs on the adjacent “east” assembly line inside Boeing’s 4-82 hangar in Renton, Washington.

To improve the aerodynamics, Boeing added a 787-like, circular tail cone to the 737 Max to fit around the exhaust vent of the Honeywell-supplied auxiliary power unit, eliminating the vortex generators found on the 737NG.

The wings for 1A003 also have arrived on the “central” assembly line, which is dedicated to supporting the 737 Max. The fuselage is still being completed inside a systems integration tool located in the adjacented 4-81 hangar, says Greg Batcher, director of the 737 Max assembly operations. The fuselage soon will be moved to the central line in the 4-82 bay, where it will enter the wing-to-body join position as the first step in the final assembly process.

No signs of the fourth flight test aircraft were visible on a Boeing tour of the central assembly line for the 737 Max. Leverkuhn says only that 1A004 will enter final assembly “later on”.

With Boeing officials already contemplating a 737 Max debut at Farnborough next year, 1A004 is assigned the most high-profile role in the test programme. It will be the first test aircraft to have a completed interior, including passenger seats, luggage compartments, galleys and lavatories.

It will be used to perform an expanded set of testing that Boeing developed for the 737 Max.

“We’re actually going to be doing things in the test card that we typically don’t do,” Leverkuhn says. “That is going to include things like performing step-climbs to understand how the engine is going to operate. We’re going to really do things that only an airline would do.”

The Leap-1B engines for the 737 Max are expected to deliver a 15% improvement on specific fuel consumption, compared to CFM56 engines being delivered to customers today. Combined with the winglets, re-lofted tail cone and other changes, Boeing still intends to deliver the 737 Max with a 14% overall fuel burn reduction, Leverkuhn says.

Boeing has “good confidence” is CFM’s ability to meet the fuel consumption target, he adds. The Leap-1B is now expected to receive engine certification shortly after first flight of the 737 Max 8 early next year, Leverkuhn says.

The Leap-1B is designed to improve fuel efficiency partly by increasing compression levels for air entering the combustion chamber, which drives up temperatures inside the core. Although no hotter than temperatures seen in the GE Aviation’s latest widebody engines, the higher temperatures required Boeing to redesign a part of the engine nacelle that shields the thrust reverser from exposure to such heat. But the original plan to use a titanium inner wall raised concerns that Boeing supplier GKN could not deliver the part quickly enough.

Boeing has decided to switch to a material developed for the GE9X engine, which is selected to power the 777X, Leverkuhn says. Leverkuhn declines to reveal the substitute material, but he says it is closer to the conventional composite materials used for such structures in previous nacelle designs. GE’s specific approach on the 777X engine inner wall is not known, but the company has recently developed a new material – oxide-based ceramic matrix composites – to perform a similar role on the Passport engine for the Bombardier Global 7000 and 8000.

Boeing has accumulated 2,931 firm orders for the 737 Max before the first test aircraft rolled out of the factory, but that’s still nearly 1,500 aircraft short of the Airbus A320neo family backlog. Despite Airbus’ 60% share of the market, Leverkuhn emphasises that Boeing launched the 737 Max nine months after the A320neo, when Airbus had already accumulated more than 800 orders.

Since the 737 Max was launched, Boeing’s share of the single-aisle order market against Airbus is closer to 45%, but Leverkuhn describes that as “around 50%” of the market.

“We’re very comfortable with the way the market is settling out, which is 50-50 [market share split],” Leverkuhn says, adding that’s “not unlike where we are with the NG and the A320 family right now. I would expect that to continue to go on. It’s a dogfight in every campaign.”

Updated with photos from the rollout event.

Source: Cirium Dashboard