WCA March 2010

As those modifications were being made, Boeing’s refusal to disclose the basic weight of the empty plane gave rise to speculation on its problems. Mr Gates cited a research note from last October by Morgan Stanley financial analyst Heidi Wood, who downgraded Boeing’s stock at the time: “The 787 appears to have evolved from a once-elegant composite design to one saddled with carbuncles of heavy titanium added throughout for strengthening.” Apparent vs real weight gain While the briefing document issued to the airlines in December gave the maximum takeoff weight of the 787 as 9.25 tons heavier than in the original version, the chief engineer on the project told the LA Times that weight has in fact been stable. The apparently higher figure was explained as representing the plane’s allowed operational weight, bumped up by Boeing after modelling and analysis showed the structure to be strong enough to carry extra-high loads. Engine makers Rolls-Royce and General Electric are working on improving fuel consumption on the 787. According to the Boeing engineer, that, together with weight and drag reduction and other improvements, will compensate for the fuel-burn penalty that comes from added weight.

Perhaps wishing not to be the ghost at the feast in Seattle, aerospace reporter Dominic Gates of the Seattle Times also took to the pages of the LA Times to sound a cautionary note on the question of just how much the 787 weighs. Just days before the maiden flight, Boeing published a document for airlines that suggests to experts that the plane exceeds its original target weight by a few tons. (“Boeing’s 787 Dreamliner Is No Lightweight,” 23 rd December) Industry observers have been tracking Boeing’s efforts to reduce the weight of the 787 since its roll-out in 2007, heavier than expected from the first. Mr Gates need not have spelled out the significance of weight, but he did: a heavier plane burns more fuel per trip, for correspondingly higher fuel costs. Some 55 airlines have 840 firm orders in place for the pioneering composite-plastic plane, on the basis of Boeing’s projections for the 787’s payload, range, and fuel efficiency. These all go down as weight goes up. “Excess weight is a constant worry in any new airplane program,” Mr Gates wrote. “On the composite-plastic 787, the concern was amplified [last year] when Boeing discovered a structural flaw in the design and had to reinforce sections of the wing-body joint with titanium fittings.”

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Wire & Cable ASIA – March/April 2010