Faced with a potentially prolonged investigation into what caused batteries on two Boeing 787 Dreamliner jets to catch fire or emit smoke last month, Boeing's European rival, Airbus, said Friday that it had abandoned plans to use the same battery technology on its forthcoming wide-body jet, the A350-XWB.
Airbus said that it began informing airline customers on Thursday that it would not move ahead with an original plan to use the lightweight lithium-ion batteries to power a number of the A350's onboard systems, and would revert instead to a conventional battery, made of nickel-cadmium, that is already used extensively on existing Airbus models.
"Airbus considers this to be the most appropriate way forward in the interest of programme execution and reliability," said Marcella Muratore, an Airbus spokeswoman.
Airbus completed the assembly of its first test version of the A350 late last year and initial ground tests of that plane using the lithium-ion batteries had already begun at its factory in Toulouse, France. By switching gears now, the company said it hoped to be able to stick to its schedule of delivering the first aircraft in the second half of 2014.
Investigators at the US National Transportation Safety Board have not determined the root cause of two episodes in January involving fire or smoke from the 787's lithium-ion batteries, which are made by a Japanese company, GS Yuasa. The incidents prompted the US Federal Aviation Administration to ground all 787s on January 17.
In recent weeks Airbus executives had indicated their concern that the continued uncertainty about the cause of the 787 battery problems, as well as the nature of any fixes that might be ordered by the FAA and its European counterpart, the European Aviation Safety Agency, might endanger the A350's development schedule, leading to potentially significant compensation payments to airlines.
Airbus currently has 617 orders for the A350 from 35 airline customers.
Muratore, the Airbus spokeswoman, stressed that the company remained confident that the lithium-ion battery system that it had been developing with its French supplier, Saft, was "robust and safe," and added that Airbus planned to use lithium-ion batteries on the A350s it will use for flight tests scheduled to begin this summer.
The decision to revert to nickel-cadmium batteries, she said, was made purely for commercial reasons.
"As a result of making this decision now, Airbus does not expect it to impact the entry into service schedule," Muratore said.
The Boeing 787 is the first commercial airliner to make extensive use of lithium-ion batteries. Prior to the A350, Airbus had only used the technology to power a limited number of auxiliary functions on its twin-deck A380 superjumbo, which entered service in 2007.
Battery makers have promoted lithium-ion batteries as being significantly lighter and faster to recharge that nickel-cadmium batteries. Promotional materials from both Yuasa and Saft have also described the technology as requiring significantly less maintenance that conventional batteries, reducing operating costs for airlines.
But investigations by Japanese and US regulators in recent weeks have revealed that airlines had experienced multiple problems with the 787's batteries before the overheating incidents in January, raising questions about their reliability.
Battery experts say that while lithium-ion batteries weigh 30 per cent to 40 per cent less than conventional batteries, their contribution to the overall weight of a jetliner is minimal: The empty weight of a Boeing 787, for example, is about 242,000 pounds or 110,000 kilograms; its two lithium-ion batteries weigh 63 pounds each.
Muratore of Airbus said that it was too early to say what, if any, impact the battery switch may have on the A350's fuel-efficiency or other performance targets. But she stressed that weight ''was not a factor'' in the decision. She added that the dimensions of the nickel-cadmium batteries were not expected to be significantly larger than those of the four lithium-ion batteries they will replace, reducing the design adjustments that will have to be made.
Airbus said it was too early to estimate the financial impact of making the battery switch. But analysts said it was likely to be minimal compared to the potential burden of hundreds of millions of dollars in penalty payments to customers in the event of a delivery delay.
"I think this probably gets lost in the wash," said Nick Cunningham, an aerospace industry analyst at Agency Partners in London. "You're probably only talking about a few million dollars."
He estimated that the added weight of the nickel-cadmium battery was probably equivalent to losing one passenger seat of payload. "That's likely to be well within the margin of guarantees" on performance that Airbus has made to airlines, he said. "This seems like the thoroughly sensible thing to do."
Aviation regulators have long known about the risks of lithium-ion batteries, which are more prone to overheating if improperly charged or discharged. Because of their unique chemistry, a fire that begins in one cell of a lithium-ion battery is difficult to extinguish and can rapidly spread to neighboring cells -a condition known as thermal runaway.
The technology was nonetheless approved by the FAA, the EASA and regulators in other countries for use on the 787 in 2007, with the provision that Boeing employ a series of additional safeguards to contain smoke and fire in the event of an incident.
Airbus said that it would continue to study the lithium-ion technology as it moves forward with the A350's development and would "take on board" any relevant findings that resulted from the ongoing investigation of the Boeing 787 incidents.