Boeing to Inspect Wings of Undelivered Dreamliners for Cracks Airplane Maker Says Supplier's Manufacturing Defect Could Cause Delays in Delivering the Jets
Boeing Co. revealed Friday that a manufacturing problem had caused hairline cracks in the wings on some of its 787 Dreamliner jets, requiring inspections on 42 aircraft and delaying the delivery of some to airlines. Wing-maker Mitsubishi Heavy Industries Ltd. informed Boeing that a change in its manufacturing process may cause the cracks in the wings it produces for yet-to-be-delivered jets, according to a spokesman for the U.S. aerospace giant. Subsequent inspections revealed cracks on some jets, the spokesman said. The defect is a major headache for Boeing, which is working to consistently produce 10 Dreamliners a month this year, though it still plans to deliver around 110 of the jets in 2014 and said its revenue guidance for the year remained unchanged. The inspections and repairs at Boeing plants in Washington state, South Carolina and Mitsubishi facilities in Japan illustrate how manufacturing problems can be spread quickly through the supply chain while it builds Dreamliners at a record rate. Boeing said none of the 123 787s delivered to date are affected by the wing issue. A person familiar with the issue said the company was told by Mitsubishi in the second half of February of the issue after its routine quality checks. "We will work with customers to adjust delivery schedules as required," said the spokesman. Boeing and its partner are inspecting 787s with line numbers running from 151 to 193, representing around a fifth of all Dreamliners built since 2007, according to the same person familiar with the issue. The latest problem to affect the Dreamliner program stems from fasteners used to connect the wing ribs to the shear ties on the carbon fiber composite wing panel, according to two people familiar with the situation. The fasteners were over-tightened without the use of manufacturing fillers, compressing a gap in the structure and in some cases caused hairline cracks of less than an inch to carbon fiber composite shear tie that connect the rib to the lower skin of the wing panel. If left unchecked, it can cause unintended stress on the jet's structure and could lead to further damage. "We understand the issue, what must be done to correct it, and are completing inspections of potentially affected airplanes. We are addressing affected airplanes as required," said the spokesman. The manufacturing defect is a rare significant quality defect for the Japanese aerospace supplier, whose quality has traditionally been a model for Boeing to emulate inside its own factories. Mitsubishi wasn't immediately available for comment. A Boeing supplier in Italy made a similar manufacturing error discovered in 2010 when assembling horizontal tails for the Dreamliner, requiring significant rework to dozens of aircraft. Mitsubishi builds the entire carbon fiber composite 787 wing at its Nagoya, Japan, factory before it is shipped by a heavily modified 747 to Boeing's final assembly lines in Everett, Wash., and North Charleston, S.C. Japanese suppliers build 35% of the Dreamliner, the first jetliner to be made from a majority of carbon fiber composites. A spokesman for Boeing said it expects each airplane will take one to two weeks to inspect and correct, depending on its position in the production process. About 17 of the 42 aircraft are fully completed and seven have been undergoing pre-delivery flight tests, according to external sources tracking the program. The rest of the 787s are in various states of assembly or the wings are still in Japan and have yet to be shipped for final assembly. The company said its 2014 revenue guidance of between $87.5 billion and $90.5 billion remains unchanged, and that it still plans to deliver 110 787s this year. However, deliveries planned for the first quarter could slip beyond March, the close of the company's first quarter.