Boeing is rushing to add two composite fuselage barrel sections to its 787 test programme after what was intended to be the ninth and final test specimen failed quality inspections last month.
Despite the setback, Boeing is adamant the 787 development schedule is on track for the start of flight tests by August 2007.
Boeing says the problem was revealed when it carried out non-destructive inspection (NDI) of a 9m (33ft)-long constant test section that had been built to assess a different mandrel tool and production process.
The ninth test section had been added to check "improvements" to the process, says Boeing, which adds that tests on the previous eight completed sections "have all gone well". It says: "We did external NDI and got porosity indications." The manufacturer has begun work on two extra barrels to conduct separate testing concurrently. "That’s how we can still stay on schedule," it maintains.
Boeing says the revised process caused trapped gases to bubble when the lengthened section was being baked in the autoclave at the Developmental Centre site at Boeing Field. The NDI revealed "excessive porosity", but "was not a structural test", adds the company. "We have got a team figuring out the root cause, but they haven’t come to any conclusions," it says.
The two extra barrels will be developed using the previous method used to produce the earlier, successful sections. "We have informed the [US Federal Aviation Administration] and they have approved the plan."
Boeing adds that "while this was a pop-up for sure, this is why we are doing it. It’s all about proving the technology at the development stage. If this was the first production barrel then we’d be very upset."
In the meantime other software integration issues have cropped up as part of the the development of a “software package that covers the lifecycle of the aircraft - from design to manufacturing to support”, the company acknowledges. “There have been cases when some software systems have had challenges talking to each other. We are developing solutions among the systems as we do more and more integration and the entire system is maturing. We are now at 25% engineering release, which is a sign the system is working,” it adds.
Source: Flight International