New glitch reported in Dreamliner
By Julie Johnsson Tribune reporter 5:17 p.m. CST, November 13, 2009
Boeing Co. engineers discovered yet another problem with the 787 Dreamliner this summer as they raced to deal with the latest cause of delays with the star-crossed jet: structural weaknesses where its wings attach to the frame.
Metals bolts known as "freeze plugs" had damaged composite materials in the wing of one of the six planes that Boeing plans to use in flight tests, engineers found. They strongly recommended that the plane remain grounded until the problem is fixed, the Wall Street Journal reported Friday.
A spokeswoman for Chicago-based Boeing provided few details of the incident, aside to say that the problem had been "resolved" and to confirm that the 787 remains on track to take its first flight late next month.
Delamination over time can lead to structural failure in a composite, a super-hardened plastic that Boeing is using extensively in place of metal in the new plane. Boeing wouldn't say if similar corrosion was found in other Dreamliners.
The 787, which is running nearly three years behind schedule, relies on composites to a greater extent than any other commercial jetliner. The space-age materials, which are stronger and lighter than metal, are designed to make the plane more fuel-efficient.
However, Boeing has encountered problem after problem as it tries to get the best-selling jet into the air for the first time. Critics conted Boeing was too ambitious with the Dreamliner, attempting to build a ground-breaking airplane while retooling its manufacturing to place much of the responsibility for design and assembly in the hands of suppliers.
The plane's first flight was originally scheduled for late summer 2007 but has been postponed repeatedly as Boeing grappled with glitchess that have included a shortage of titanium fasteners, coding issues, paperwork snarls and suppliers struggling to meet Boeing's ambitious production schedule.
The latest postponement came in June as suppliers, airline partners and journalists prepared to trek to Everett, Wash., to witness the 787's first flight, a key milestone. Boeing called off the festivities and revealed the 787 frame had shown unanticipated structural weakness in testing in a critical area, where the wings are joined to the fuselage.
Over the summer, Boeing's engineers devised a fix, installing new fittings in 34 locations on the first test-flight aircraft. They plan to finish work on the second flight-test plane shortly, Boeing announced Thursday.
Boeing hasn't completed installing the reinforcements on its static-test airframe. Until it does so, Boeing won't be able to fully test whether its fix worked.
"Once the installations are complete the team will re-fit the strain gauges and other instrumentation necessary to prepare for the test, which will occur later this month," said Mary Hanson, a Boeing spokeswoman. "We've done a significant amount of static and fatigue testing at the subcomponent level and are confident we have the right approach."