The plastic Boeing 787
The following is an article from "The Times" of the 7th January 2006 which I found interesting. Obviously a sales-inspired broadside by Airbus, but worthy of mention. Perhaps others would care to comment.
Passenger aircraft rivals clash over safety of fuselage built from plastic
By Ben Webster, Transport Correspondent
THE world’s two leading aircraft manufacturers are engaged in a bitter dispute about the safety of a new airliner being made almost entirely from reinforced plastic.
Airbus has accused Boeing of making a giant leap without fully comprehending the risks of swapping metal for a composite of plastic and carbon fibre.
The Boeing 787 Dreamliner will be the first passenger jet with fuselage and wings made from composites rather than aluminium.
Composites can hide damage that can spread under the surface. The structure may appear sound until the moment it shatters. Reinforced plastic has been used for 20 years in the rudders and tailfins of airliners, but no manufacturer has previously dared to use it to make the fuselage.
Tennis rackets, fishing rods, bicycles and Formula One cars are often made from composites. But the 787, which will carry up to 300 people, will be the largest structure made from the material.
Airbus pioneered the use of composites in 1985 in the tailfin of the A310, and it is going a step farther in the A350, the rival to the 787, by making the wings from composites. But the European manufacturer, which will build the wings at Broughton, North Wales, has angered Boeing by asserting that the material is too risky to use composites for a fuselage.
Boeing is switching to reinforced plastic because it is cheaper to maintain and lighter than aluminium. Boeing says that the 787 will use 20 per cent less fuel and be 30 per cent cheaper to maintain than existing aircraft.
Boeing has previously been cautious about employing composites but intends to leapfrog Airbus in its use of them.
An Airbus spokesman said: “Boeing has missed out on several smaller steps in using composites so it is trying to do it in one giant leap. There is a certain amount of risk that goes with that.”
He said that the fuselage, unlike the wings, was prone to being damaged by impacts with luggage loaders, catering trucks and passenger jetways.
“You get a surprising amount of times when people dent or tear the fuselage skin by driving vehicles into it,” the Airbus spokesman said. “It’s more difficult to detect the extent of the damage with carbon fibre. You don’t know whether it has spread six, twelve or even twenty inches to the left or right.
“A metal component absorbs energy and deforms, so the damage tends to be localised. A carbon-fibre skin doesn’t deform before it breaks.”
Airbus has previously been forced to defend its own use of composites. The composite rudder of an Airbus A300 snapped shortly after take-off from JFK airport in New York in November 2001, causing a crash that killed 265 people. Investigators blamed the pilot’s excessive use of the rudder but have recently faced demands to reopen the inquiry after defects were found in the rudders of two other A300s. Airbus suggests that the 787 will be grounded for long periods for repairs because composites cannot be patched as easily as aluminium. Boeing believes that Airbus is trying to cause alarm among the airlines to boost sales of the A350.
The 787, which is scheduled to enter service in 2008, two years before the A350, has so far proved more popular among airlines, including Britain’s First Choice Airways. Airlines have ordered 291 787s, compared with 172 A350s.
Airbus has previously tried to exploit concerns over the safety of Boeing aircraft. Four years ago it claimed that four engines were better than two on long flights. The A340 has four engines and its Boeing rival, the 777, has two. Airbus dropped that claim after launching the A350, a long-haul aircraft that has two engines.
Dr Paul Robinson, head of the Composites Centre at Imperial College, said that layers of composite material could become separated without any visible change on the surface. He said: “You would be able to detect a dent by eye in a metal structure, but in a composite there may be no dent.”
However, he said that Boeing could counter the problem by making the composite fuselage so strong that it would resist all but the heaviest impacts. He said that strict inspection procedures would also be needed to ensure that the structure was properly checked after impacts.
The problem for Boeing is that, whereas a visual inspection is usually adequate for aluminium, a much more time-consuming ultrasound scan may be needed to detect underlying damage to composites. An airline that is under pressure to meet a tight schedule may be tempted to take risks and ignore apparently minor defects.
A Boeing spokesman said: “The composite fuselage will be so strong that if there is no visible damage, no repair will be required.”