Boeing 737MAX

Boeing reaffirms mid-year target for 737 decision
By Michael Gubisch

Boeing has restated its aim of announcing its plans for the 737 - whether to re-engine or to go for a completely new, clean-sheet design - by the middle of the year.

However, according to John Tracy, Boeing's chief technology officer, the decision will be guided by the availability of engineering resources, given the potential demands from a 777 update and the development of derivatives of the 787.

Whether a new single-aisle family will find more demand than an updated version of the 777 is the "big question" being discussed at the company, says Tracy.

The 777 will face a certain amount of competition once the A350-1000 enters service. Boeing is considering replacing the 777's aluminium wing with a composite structure as one option to update it, but has also contemplated a completely new design.

Meanwhile, in the narrowbody segment, pressure is mounting on Boeing to respond to the challenge posed by the Airbus A320neo, which has gathered more than 330 orders since its launch in December.

Summing up the challenge, Tracy says: "We are pretty much committed not to have two major development programmes going on simultaneously, [and] to get the right people on the right job at the right time."

The future single-aisle strategy will therefore be determined by the "firing order" of different new models. These include further development of the 777 and 787 derivatives, such as the stretched 787-9 that is due to enter service in 2013.

Tracy adds that the 777's future will be revealed "soon after" determining the strategy for the 737, indicating a decision on the large twinjet in the second half of this year.


Unlike Airbus, which maintains that "game-changing" technology for a next-generation narrowbody aircraft will not be available until around 2025-30 - particularly with regard to the propulsion system - Boeing takes a more sanguine view of the pace of technological advancement.

Tracy believes that the development of new technology would not be the main hurdle for a clean-sheet aircraft programme, he says. Unsurprisingly, Tracy dismisses Airbus's view on the apparent lack of maturity of advanced engineering. "I am a technologist, so I am never going to say that technology is going to limit us," he says.

It is not clear whether a brand-new single-aisle aircraft would follow the 787's lead and have one or both of the fuselage and wing made from composite, or whether it would stick with an all-metal construction. Tracy confirms that Boeing is looking at advanced metals, such as aluminium-lithium alloy, and composites.

Aside from achieving traditional aerospace objectives, such as lower weight, greater strength, better fatigue life characteristics - and in the case of engine components, higher temperature resistance - the construction material for a new aircraft must ensure ease and speed of manufacturing.

This is crucial for the high-rate production of single-aisle aircraft. Boeing plans to increase its monthly 737 output from the current level of 31.5 to 38 aircraft by the second quarter of 2013 and will consider taking this beyond 40 in future (just shy of the Airbus's planned rate of 44 on its A320 line).

The monthly 787 production rate, on the other hand, is to rise from the present two aircraft to two-and-a-half by mid-2010, reaching 10 aircraft in 2013.

Tracy signals that the time required for composite construction, as employed on the 787, would pose a challenge for a narrowbody jet, suggesting that a metal-based design is more likely.

"The composite manufacturing process today requires one to lay down material with some sort of machine and then put it into an autoclave to cure it. That takes a lot of time Can you get enough of those [production] machines in the right place at the right time or is some other approach that we need for a more rapid manufacture? Is the advantage we get with composites outweighed by the additional time to manufacture them?"

He adds that Boeing is investigating alternative technologies "to see if we can eliminate some of those manufacturing constraints".

Another challenge in developing a next-generation narrowbody will be to determine its optimum size. As with the 737 and A320 families, a new design will lead to a baseline model that can be stretched or shrunk for different capacity and performance demands.

However, especially with the smallest 737-600 and A318 models failing to generate significant sales, and Bombardier's Cseries entering the market at the lower capacity end, there have been questions whether the 737/A320 families straddle too wide a range. Critics suggest that a better course of action would be to develop two separate aircraft.

Tracy disagrees with that analysis, but believes that a slightly larger aircraft will be the preferred option. "I think it will be a similar pattern with a base model that covers a [capacity] range," he says. "There is a good chance that range will be shifted up a little bit."

http://www.flightglobal.com/articles/2011/04/26/355990/boeing-reaffirms-mid-year-target-for-737-decision.html

oeing's response to the A320neo is likely to be both a higher-performance 737NG ready by 2015 and an all-new aircraft, which will probably be a light twin-aisle entering service in 2019 or 2020, according to an assessment by Buckingham Research Group.

In a client report issued following Boeing Capital Corp.'s aviation finance conference this week, New York-based Buckingham said that Boeing "is considering a range of options for a new aircraft and believes the technology—propulsion, materials, avionics, etc.—will be available to support a service entry in 2019/2020" (ATW Daily News, April 19).

However, the firm said the "new aircraft should not be considered a replacement for the 737, 757 or Airbus narrowbodies … Like the 707, which first replaced turboprops with turbojets, the 747, which first introduced jumbo capacity, and the 777, which first introduced four-engine capacity with a two-engine airplane, Boeing's new aircraft will likely address a new market with new capabilities."

Interestingly, Buckingham reported that a "meaningful number of investors" still believe that Boeing will re-engine the 737NG. "Our view has consistently been that Boeing will not re-engine, but a number of investors acknowledge the possibility that Boeing might re-engine if a major 737 customer defected and ordered the A320neo," it said, noting, "Boeing may be so capacity-constrained [with orders] that it may not have the option to re-engine the 737."

It added, "Internally, Boeing appears convinced that the 737NG's projected 2016 performance is competitive with the A320neo ... The finance community and lessors are urging Boeing to wait and leap ahead with a new aircraft versus a derivative."

Buckingham also believes that Boeing may forgo bidding on the upcoming Delta Air Lines RFP for 200 A319-sized aircraft. "We think that Boeing already factors in some near-term share loss as a result of its product strategy and that it expects to regain the market share high ground with a new airplane later in the decade," it stated.

He reiterated that a decision on a 737NG replacement or re-engine would be made at the end of the year. Boeing VP-Business Development and Strategic Integration Nicole Piasecki said that the baseline Boeing would protect for a "737 replacement is 125 seats."

The company is looking at both single-aisle and twin-aisle models as a replacement for the 737. Answering a question from ATW, Piasecki said that even at 125 seats, a twin-aisle solution would work. Boeing VP-Advanced 737 Product Development Mike Bair said that a twin-aisle aircraft would reduce turn times, enabling airlines to add more sectors per day. The twin-aisle would only incur a fuel burn penalty of 2%-3% compared to a single-aisle, he added.

Piasecki told ATW that the twin-aisle option is getting strong support in Asia and China.

Raked wingtips are a feature on some Boeing airliners, where the tip of the wing has a higher degree of sweep than the rest of the wing. The stated purpose of this additional feature is to improve fuel efficiency and climb performance, and to shorten takeoff field length. It does this in much the same way that winglets do, by increasing the effective aspect ratio of the wing and interrupting harmful wingtip vortices. This decreases the amount of lift-induced drag experienced by the aircraft. In testing by Boeing and NASA, raked wingtips have been shown to reduce drag by as much as 5.5%, as opposed to improvements of 3.5% to 4.5% from conventional winglets.[13]