Manufacturer must overcome weight and other issues to achieve service entry goal for new twinjet
Boeing is confident that nothing but a major surprise in flight test will stop the seventh production 787-8 from entering service as planned in May 2008 with launch operator All Nippon Airways. Meanwhile, the airframer is chasing a reduction in the twinjet's empty weight which is 2t to 3t behind target on the early build airframes.
The service-entry schedule means Boeing must execute the fastest assembly and flight-test period for a new aircraft type in modern airliner history and overcome a series of known issues, including a stubborn weight problem, a shortage of key parts and an acknowledged late start compared with past airliner programmes.
Boeing's reputation as a manufacturer that delivers on schedule is not all that is at stake if the first delivery date slips. After amassing the largest orderbook in history at the time of roll-out, Boeing faces intense pressure from customers near the bottom of the bookings list to speed up production.
The public premiere on 8 July - 7/8/07 on US diaries - offered Boeing a chance to present a show of confidence backed up by 677 orders and no hint of any certain show-stoppers.
Boeing executives have only one caveat to guaranteeing on-time entry into service. "We have plans in place that would allow us to hold our May 2008 entry into servicedepending on what happens to us. Obviously, if you get a big surprise in flight test you can have problems, but we don't anticipate a lot of surprises," says Mike Bair, vice-president and general manager for the 787.
Boeing is building the first six aircraft for flight testing, but all will be refurbished later for customers. The first four aircraft will be powered by Rolls-Royce Trent 1000s, with the General Electric GEnx powering the final two aircraft. Boeing plans to keep an aggressive flight-test date to reach certification within eight months.
"This flight-test programme is about eight months. The 777 was 11 [months]," says Bair. "So it is compressed - not hugely compressed, but compressed. And, again, the way we are making that compression is ensuring that we fly the airplane at higher flight rates than we did on the 777."
Boeing engineers, meanwhile, will be busy solving the 787's persistent weight problem. Few details are known about the sources of extra weight, but the seventh production aircraft must be between 2t to 3t lighter than the flight test jets for the 787-8 to meet fuel burn and range targets. Boeing says that all areas of the aircraft are being reviewed for weight savings.
However, there appear to be few easy solutions. In May, Alcoa revealed that it would offer Boeing newly developed aluminium lithium materials strong enough to replace heavier titanium in some parts of the jet. When asked about Alcoa's offer, Bair replied that aluminium lithium is an unlikely substitute because the material makes a poor fit with composite frames.
A more immediate challenge is ensuring that flight testing begins within a roughly four-week window from late August to late September. After the pause to stage the 787 premiere in the factory bay, Boeing's mechanics face a massive, two-month effort to make the first flight date on time.
"As you guys walk away Sunday," Bair told reporters, "you'll probably see a horde of mechanics descend on that airplane to finish that up."
Major sections of the fuselage were assembled by suppliers using thousands of temporary fasteners due to a well-chronicled supply shortage. More than 1,000 temporary fasteners must be removed from the jet and be replaced with specially made parts, Bair says.
Boeing's next major task is to install all the major electronic systems, including the avionics boxes in the cockpit. That job includes delivering a series of increasingly functional software loads for the jet's on-board computers, with block 7.2 now set as the flight-ready software installation, said Mike Sinnett, director of 787 systems.
Bair, however, says that what he perceives as the key stumbling block for the Airbus A380 programme will not be revisited in the 787.
"They had a wiring configuration issue that they struggled mightily with," Bair says. "I think the A380 probably has 350 miles [560km] of wiring in it. We've got sixty-ish, so it's just a dramatically simpler package. We've got all the wire bundles for the first airplane manufactured. So we're not going to have that issue. We're likely to have other issues, but we don't think we're going to have serious issues."
Despite any concerns, Boeing executives also point how smooth many parts of the programme are running. Both the Trent 1000 and the GEnx engines are well along in development and face no known technical hurdles before certification in August or September.
Bair says GE and R-R were "challenged" because "we made them run engine programmes that were a lot quicker than we have historically". He says the manufacturers have performed well and "we don't think we're going to have any real issues when we get done certifying both engines", he adds.
Boeing also has reached a basic agreement with the US Federal Aviation Administration on the guidelines the company will follow to certificate the aircraft. There a few "open pieces of paper" unresolved, Bair says, but the regulators and the manufacturer expect that the guidelines will be complete before the flight test period begins.
With the overall 787 is aiming to set a new standard for development speed, comparisons with past development programmes for an all-new airliner may be unreliable. Bair says he believes the 787 is roughly on track with previous development efforts. However, another Boeing executive - Scott Strode, vice-president for airplane development and production - has admitted the 787 is "probably a little further behind than some".
The true measuring stick will come with the next public milestone, which is the first flight event that kicks off the flight-test programme.
"We have a window that we're shooting to get the airplane into the air, and I think as all of you know we don't schedule first flights," Bair told reporters at the premiere. "The airplane flies when it's ready. If you put a firm date on a calendar, it might make you do something you don't want to do, so we're pretty careful about how we approach the first flight of a brand new airplane."
Source: Flight International
