Europe's Airbus is considering whether to drop Lithium-Ion batteries and switch back to traditional ones on its new A350 as investigators probe Boeing 787 battery problems, several people familiar with the matter said.
The move comes amid a wider rethink in the aerospace industry on whether the powerful but delicate backup energy systems are technically "mature", they said.
Industry executives, insurers and safety officials 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.
"There is an increasing doubt over the technology," said a person familiar with industry-wide discussions on the issue. "It may well be the future but for now it is a question of maturity. The information on the two incidents is not reassuring."
The National Transportation Safety Board, which is examining a fire on a parked 787 at Boston airport a month ago, said on Thursday it had identified where the fire broke out but not the cause and referred to a possibly long investigation ahead.
A spokesman for EADS unit Airbus said the company would evaluate the outcome of the U.S. battery investigation: "Let's not get ahead of ourselves. There are no conclusions by the NTSB yet and the investigation is still ongoing."
Airbus has kept all options open, the spokesman added.
France's Saft, which makes both the new and old generation of batteries for Airbus, did not immediately respond to requests for comment. Its head told Reuters last month that Lithium-Ion would ride out the 787 problems.
The A350 would be the second large passenger jet to fly on Lithium-Ion batteries for backup electrical power after the Dreamliner, which pioneered their use in passenger transport to support an increasing array of electrical systems.
The top-of-the-line F-35 U.S. fighter jet also uses Lithium-Ion batteries, designed to kick in at short notice and start moving wing surfaces in an emergency so that pilots can land.
Airbus said last week it had a plan B for its battery design and time to respond to any changes in rules for their use.
However, experts say that if the 787 probe fails to provide clear answers soon, pressure may build for Airbus to pre-empt the findings and switch solutions to head off development risk.
The planemaker plans to make the maiden flight of its newest airliner, developed at an estimated cost of $15 billion, around the middle of the year. This will be followed by a year of flight trials and a complex certification process, during which the distraction of re-engineering could cause notable delays.
The A350 is due to be delivered in the second half of 2014, around two years behind its original schedule.
The company has said the targets are challenging.
Investigators in the United States and Japan are examining how the Lithium-Ion main batteries in the 787 suffered a thermal runaway, or overheating that can burn a battery out and create a fire that is difficult to extinguish.
Reverting to less volatile Nickel-Cadmium would mean sacrificing improvements in weight in the lighter Lithium-Ion batteries, equivalent to one adult male passenger out of between 270 and 350 passengers and cargo on board.
But this is a fraction of the 40 metric tonnes saved by the A350 compared with older planes, according to company presentations.
"The penalty in weight compared with the risks associated with Li-Ion is minimal," said Nick Cunningham, an aerospace analyst at Agency Partners in London.
Plane and battery makers say the technology is safe but recognize it is in the early stages of use in commercial flying.
Cunningham said Airbus and Boeing had learned from past development snags that it pays to tackle problems early rather than having to embark on costly refits that burn up cash.