The European planemaker said on Friday it had taken the decision to adopt the batteries used on existing models such as the A380 superjumbo in order to prevent delays in the A350's entry to service next year.

Reuters had reported that Airbus was considering such a move to limit the risks surrounding the development of its $15 billion airliner.

"We want to mature the lithium-ion technology but we are making this decision today to protect the A350's entry-into-service schedule," an Airbus spokeswoman said.

Industry executives, insurance companies and safety officials had told Reuters the technology's predictability was being questioned at senior levels as investigators struggle to find the cause of incidents that led to the grounding of Boeing's 787 Dreamliner.

These included a fire on board a parked 787 in Boston and an in-flight problem on another plane in Japan.

The A350 is due to enter service in the second half of 2014 compared with an initial target of 2012 when it was launched as Europe's answer to the lightweight 787 Dreamliner.

The industry's fear is that the failure to identify the "root cause" of the burning battery incidents leaves too much uncertainty over whether regulators will certify planes as safe when relying on the powerful but temperamental power packs.

Airbus, which has said the A350 timetable is "challenging," can ill afford such doubts over its largest ever civil plane project and so has opted to eliminate its exposure to the risk that regulators might change the rules.

Airbus will use the lithium-ion batteries for a maiden flight in mid-year and early flight trials but switch to traditional batteries in time for certification and delivery.

DOUBTS OVER TECHNICAL MATURITY

Uncertainty over whether Airbus can be sure of certifying the A350 with the new batteries, in time for delivery in the second half of next year, illustrates the scale of the task Boeing faces in persuading U.S. regulators to let it fly the 787.

People familiar with the matter say it has developed a fix involving a tough casing for the lithium-ion battery.

Without a clear cause for the battery problems and based on the same broad facts that are available to its arch-competitor Airbus, Boeing would need to demonstrate the risks are minimal.

Lithium-ion batteries have been in consumer products such as mobile phones and laptop computers for years but are relatively new to industrial applications such as back-up batteries for electrical systems in jets or energy storage on wind farms.

Both Airbus and Boeing insist the new battery technology is safe. But beyond any debate over safety, questions have arisen over its "maturity" or predictability. Engineers aim to minimize uncertainty because it translates into financial risk.

Airbus parent EADS shares rose 0.4 percent on Friday, while shares in French battery maker Saft fell over one percent. Saft developed the lithium-ion battery for the A350 but is also Airbus's supplier for older types on all models. A spokeswoman said Saft supported Airbus's decision.

Switching to the heavier nickel-cadmium will mean adding 60-80 kilogram's to the weight of the A350 -- reducing its payload capacity by the equivalent of an adult male passenger.

That is usually more than enough for planemakers to fight over when marketing the fuel savings of their jets, but Airbus has decided it is outweighed by the risks of further delay.

Boeing said last week it had selected lithium-ion batteries because they best met the performance and design objectives of the 787.

"Nothing we learned during the design of the 787 or since has led us to change our fundamental assessment of the technology," a spokesman said.

(Reporting by Tim Hepher, Dominique Vidalon; editing by Janet McBride and Giles Elgood)

By Tim Hepher

Stocks treated in this article : The Boeing Company, EADS, SAFT