(Reuters) - U.S. safety regulators are nowhere near finishing an investigation into a battery fire on the Boeing Co 787 Dreamliner, a top official said on Thursday, raising the prospect of a prolonged grounding for the aircraft.
Deborah Hersman, chairman of the National Transportation Safety Board, made clear that investigators have found a series of "symptoms" in the battery damaged in a January 7 fire in Boston, but not the underlying cause of the problem. She also said the agency would be looking at the design of the battery compartment area of the plane and whether the certification standards had been strong enough.
The comments were seen by some safety experts within the aerospace industry as a clear signal that this is no longer just a teething issue for the new plane.
That will raise questions about the financial impact for Boeing, which is still running its assembly lines and backing up aircraft to be delivered, and for airlines, many of which counted on getting the futuristic 787 for their expansion plans.
"We are early in our investigation, we have a lot of activities to undertake," Hersman told a news conference.
"This is an unprecedented event. We are very concerned. We do not expect to see fire events on board aircraft. This is a very serious air safety concern."
She rebuffed multiple questions on how long the investigation would take, making clear it could be weeks or more. She also would not say when the 787 would fly again, which is in the hands of the Federal Aviation Administration.
Former NTSB Chairman Mark Rosenker said the briefing made it clear the investigators had come up short in their hunt for the cause of the battery fire.
"It's going to take them longer," he said in an interview. "Weeks, not days."
Richard Aboulafia, aerospace analyst with the Virginia-based Teal Group, said the NTSB briefing was a sobering reminder that investigators have not made much headway on finding a cause for the battery problems.
"It was hard to find a lot of optimism on the call. It sounds like they're still in the middle of a lot of hard work and a lot of mysteries," Aboulafia said. "It just wasn't encouraging. Fire is the last thing you want on an airplane."
The 787 has been grounded worldwide since an All Nippon Airways plane made an emergency landing in Japan on January 16 after a battery incident, which Hersman said may or may not have been a fire.
That emergency landing came after a fire occurred on a Japan Airlines Co Ltd 787 on the tarmac in Boston.
In a statement late on Thursday, Boeing said it was cooperating with regulators and had teams of "hundreds of engineering and technical experts" working on the situation.
"Boeing is eager to see both investigative groups continue their work and determine the cause of these events, and we support their thorough resolution," the company said, adding it was not permitted to comment directly on the ongoing investigations.
Still, Boeing shares are actually up 1.3 percent since regulators said the plane - full of high-tech innovations that are supposed to be a model for future aviation - could not fly.
At least one customer, Poland's LOT, has already raised the prospect of seeking compensation for its losses. Another, China's Hainan Airlines Co Ltd, said this week it was disappointed in the delays and that its expansion plans had been affected as a result.
Rosenker, the former NTSB official, noted that other new planes had problems when they were introduced, but not fires, which makes this situation stand out.
"Fire is something you don't fool with," he said. "You've got to understand that, particularly given the short period of time the aircraft has been flying."
Boeing has said in the past that, because of their chemical composition, these batteries are difficult to extinguish once they catch fire. As such, the plane is designed to contain fires while they burn themselves out.
Hersman, talking to reporters after the news conference, confirmed that there is no fire suppression system in the area where the battery burned, nor any way to access it in-flight.
Asked if the lack of a fire suppression system in the battery compartment was a design flaw, she said: "We'll certainly be looking at the design and we'll be looking at the certification standards to determine if they were robust enough."
If regulators do decide design changes are needed, that could have implications for Boeing's European rival Airbus and its future A350 jetliner.
"We believe so far we have a robust design, however we will draw the lessons from the 787," Airbus Chief Executive Fabrice Bregier told Reuters Television at the World Economic Forum in Davos.
Billed as Europe's response to the Dreamliner, the A350 is due to enter service next year using lithium-ion batteries, but without the same reliance on electrical systems as the 787, something Airbus says will put less burden on the batteries.
However, Airbus has so far declined to comment on how it would tackle a battery fire if one did break out on board.
On Thursday, FAA and NTSB inspectors visited a UTC Aerospace Systems plant in Phoenix, although a company spokesman declined to say what they focused or how long they would be at the plant. UTC makes the aircraft's auxiliary power unit.
Fiona Greig, a spokeswoman for Securaplane, which makes the battery charging unit and start power unit, said its equipment was tested and worked as it should. She declined comment when asked about the issues mentioned in those units by the NTSB.
The 787 program was already years behind schedule before last week's grounding, which means Boeing cannot deliver newly manufactured planes to customers.
That means customers such as United Continental Holdings Inc may have to wait even longer for planes on order. The company's United Airlines already flies six Dreamliners.
"History teaches us that all new aircraft types have issues and the 787 is no different," United Continental Chairman and Chief Executive Jeff Smisek said during the carrier's earnings conference call. "We continue to have confidence in the aircraft and in Boeing's ability to fix the issues, just as they have done on every other new aircraft model they've produced."
Smisek said on Thursday that the carrier still expects to take delivery of two more 787s in the second half of the year.
Boeing has already delivered 50 of the 787s. Around half have been in operation in Japan, but airlines in India, South America, Poland, Qatar and Ethiopia are also flying the planes, as is U.S. carrier United.
The grounding of the Dreamliner, an advanced carbon-composite aircraft with a list price of $207 million, has already forced hundreds of flight cancellations worldwide.