US aerospace giant Boeing said late Friday that it had suspended deliveries of its new 787 Dreamliners until safety experts resolve battery and electrical systems problems, but continues to build the aircraft.
The announcement capped a week in which all 50 787s in service around the world were grounded on orders from multiple aviation authorities to investigate the cause of two incidents, including a fire, linked to its batteries.
"We will not deliver 787s until the Federal Aviation Administration (FAA) approves a means of compliance with their recent Airworthiness Directive concerning batteries and the approved approach has been implemented," a Boeing spokesman said.
"Production of 787s continues," he said.
Dreamliners had been flying in Chile, Ethiopia, India, Japan, Poland, Qatar and the United States until their flights were stopped after a global alert issued by the US FAA.
Boeing's chairman and chief executive Jim McNerney in a statement to employees defended his company and the aircraft against "the negative news attention over the past several days."
"As everyone inside the company knows, nothing is more important to us than the safety of the passengers, pilots and crew members who fly aboard Boeing commercial and military aircraft," he said.
"We have high confidence in the safety of the 787 and stand squarely behind its integrity as the newest addition to our product family."
His comments came as US and Japanese experts began examining an All Nippon Airways 787 forced to make an emergency landing at Takamatsu in southwest Japan on Wednesday because of a smoke alert apparently linked to a lithium-ion battery, the plane's main electrical power unit.
"We removed the battery yesterday and are today inspecting the plane and its components, alongside the US officials," said Japan Transport Safety Board spokesman Mamoru Takahashi.
A picture released by the JTSB showed scorch marks on the blue casing of the battery. Much of what looked like wiring around the eight cells of the battery -- the plane's main electrical power unit -- was disfigured.
It was the second incident involving the battery, and one of several problems since the beginning of the year, including a taxiing 787 sprouting a fuel leak in Boston.
The problems have cast a cloud over the aircraft heavily dependent on pioneering electrical systems and lightweight composite materials that is meant to be Boeing's future.
No airline has cancelled purchases for the 787, but with 850 of the ambitious $200 million-plus aircraft on order, a fortune is at stake.
Mr McNerney stressed that since they entered service in October 2011, 787s have completed 18,000 flights and 50,000 flight hours with no serious problems.
But US Secretary of Transportation Ray LaHood told NBC television that the 787 would have to prove itself again to US inspectors.
"Those planes won't fly until we're 1,000 per cent sure they are safe to fly," said LaHood on Friday.
The focus of investigators was on batteries supplied to Boeing by Japan's GS Yuasa through France's Thales, two of many firms in a complex global chain of suppliers for the 787 program.
JTSB investigator Hideyo Kosugi said one theory was that there may have been insufficient protection offered by the batteries' surrounding electrical system.
"I'm sure that too much current or too-high voltage has gone to the battery," Kosugi told reporters.
Loren Thompson, an aviation analyst at the Lexington Institute, said Boeing was under heavy pressure "to find a solution as soon as possible," or else it will stop receiving payments for the aircraft on order.
"It's a question of weeks, not months," he said.
Boeing's engineers union, representing 23,000 staff, raised the stakes in the case on Friday as its representatives rejected the company's "final" contract offer and blamed the 787 problems on the manufacturer's outsourcing strategy.
The union members will likely vote next week on whether they agree to reject the contract offer, and that ballot could include a vote on whether to go on strike.
"Boeing corporate created the 787 problems by ignoring the warnings of the Boeing technical community," said Joel Funfar, one of the union negotiators.
"Now, they propose to double down on their failed outsourcing strategy by outsourcing the engineering work required to solve the problems caused by previous rounds of outsourcing."