The American plane manufacturer Boeing said on Friday that 40 exemplars of its 787 Dreamliner, that are currently still in production, show signs of cracks on their wings.
The Dreamliner will be the first jet to be built using a majority of components made of carbon fiber, 35 per cent of which are supplied by Japanese companies. The lighter composites used for the production will lower its weight and allow the plane to reduce fuel consumption by 20 per cent compared to traditional airplanes of the same size.
Boeing announced that the damages do not pose any risks for travellers, as they were found on planes that are still being tested by the company and will be quickly repaired before the final delivery.
The problem is only the latest in a series of technical issues that have been delaying the production of the Dreamliner since its beginning in 2011 and occurred just after the company had decided to beef up production to 10 planes per month in 2014.
Last year, Boeing was forced by global regulators to stop deliveries of the 787 Dreamliner for three months, after problems of overheating were detected in the plane’s lithium-ion batteries.
Despite the latest defect, that is destined to cause some delay in production and additional costs for repairs, the company spokesperson Mark Birtel said that the Boeing plans to deliver 110 Dreamliners by the end of the year as previously planned.
This time the flaw seems to have been caused by a change in the manufacturing process of the wing by the Japanese company Mitsubishi Heavy Industries, which builds special carbon fiber wings for the 787 model that are then shipped to the Boeing assembly lines in the US.
On Friday, Boeing said that the cracks showing up on the 787 Dreamliner are caused by the fasteners used to connect shear ties on the wing ribs to the wings panel and that it might take one to two weeks for each plane to be fixed.
Despite the reduced dimensions of the cracks, normally known as “hairline cracks” due to their almost imperceptible dimensions, The Seattle Times reported aviation engineer Hans Weber as saying that the problem should be fixed promptly, as no airline would ever purchase planes showing structural imperfections.
The fact that the small damages occurred in planes that are still in production makes their reparation more urgent, says Weber. Small cracks in the wing ribs can actually increase in size during the flight, due to the load and pressure exerted on the plane structure.
So-called fatigue cracks are not uncommon in airplanes, but they usually show up after years of service and they are very costly. The hairline cracks found on the 787 are not likely to be a big headache, as the company know their exact location and the causes.
While some experts have claimed that the cracks on the wings of the 787 Dreamliner are easily fixable problems, the latter show that Boeing is caught in yet another unexpected setback in production which is likely to translate into high repair costs and image damages for the company.
By Stefano Salustri