WRAPUP 1-United Air backs Boeing ahead of gov't statement on 787

* NTSB due to expand on probe Thursday afternoon

* Board also consulting whistleblowers

* United says it still expects deliveries

WASHINGTON, Jan 24 (Reuters) - U.S. safety regulators will update their probe into battery fires on Boeing Co's 787 Dreamliner on Thursday, as key customer United Airlines stood by the jet and said it expects more of them soon.

The 787 has been grounded worldwide since Jan. 16 after a series of fires, including one that caused an emergency landing in Japan. Boeing and its regulators have said they do not know when the plane will fly again.

The National Transportation Safety Board will hold a news conference Thursday on its investigation into the first fire, which struck a Japan Airlines Co Ltd 787 in Boston this month.

The NTSB is also looking at multiple whistleblower claims as part of its probe, including one related to the chargers for the 787's highly flammable lithium-ion batteries.

"We have been notified about whistleblowers and are pursuing that information where warranted," a spokeswoman said.

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 like 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 Thursday 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 plane with a list price of $207 million, has already forced hundreds of flight cancellations worldwide.

AIRBUS IMPACTS

The head of Boeing's European rival Airbus said it would study the 787 Dreamliner design review and make any changes to its future A350 jetliner that may be needed as a result of the U.S. findings.

"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.

"We will look at the recommendations and guidelines of the FAA and if by chance we need to change it we have plenty of time because this aircraft, the 350, will be delivered to our first customers not before the second half of 2014 so it is not a challenge and it is not a burden for us."

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 not said in detail how it would tackle a battery fire if one did break out on board.