DailyFinance: Is Boeing's 787 safe to fly? - by Peter Cohan

Boeings 787 Dreamliner - are composite materials used unsafe in aircraft?

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Is Boeing's 787 safe to fly? - by Peter Cohan

Yesterday, Boeing (BA) announced its fifth delay in the delivery of its latest aircraft, the 787 Dreamliner. Boeing has 865 orders for the $178 million aircraft, which is designed to cost 20 percent less to operate and maintain. A big reason for these savings is the 787's use of composite materials -- for example, All Nippon Airways, which is to be first to receive the 787, said in April that fuel savings and higher revenue from the higher capacity 787 could add $100 million in fiscal 2011. But the very composite materials that are saving money for airlines are now contributing to the problems that delayed the 787 for the fifth time. And those problems raise questions about whether it can ever be safe to fly -- which would probably scare passengers from boarding the 787. In order to understand why the 787 might be unsafe, it is crucial to understand more about the 787's composite materials -- including carbon fiber reinforced epoxy tape. Older aircraft are made of aluminum, which is heavier than the composite material.

Composites are lighter and stronger hence able to fly more fuel efficiently. But engineers don't completely understand how aircraft made of composite materials will respond to the stresses of actual flight. This incomplete understanding is reflected in the computer models they use to design the aircraft. The reason for the fifth delay is that the actual 787 did not behave the way the model predicted.