Tokyo:
Regulators on Thursday grounded nearly all of the world's 787 Dreamliner fleet until a fire risk linked to the plane's batteries is fixed, deepening a crisis for US titan Boeing that threatens to last weeks.
Authorities in Japan, Europe, India and Chile followed the lead of the US Federal Aviation Administration in ordering an indefinite halt to all flights, after a Japanese Dreamliner on Wednesday was forced into an emergency landing.
The FAA, whose remit overseeing all US-made planes extends around the world, highlighted "a potential battery fire risk in the 787" after a suspected leak emerged as the focus of inquiries into the aborted All Nippon Airways flight.
Analysts said the ANA incident, following a series of safety scares involving the Dreamliner, needed careful crisis management from Boeing, which is staking its future on the next-generation plane.
The aircraft relies on battery-powered electronics rather than the hydraulics used in older planes. Boeing says its use of lightweight composite materials is a breakthrough for airlines anxious to cut fuel costs.
Boeing chief executive Jim McNerney said the company "deeply regrets" the impact of recent events on airlines and passengers, and vowed to take "every necessary step" in concert with the FAA to resolve the problems.
However, he stressed: "We are confident the 787 is safe and we stand behind its overall integrity."
As a result of the mishap on the domestic ANA flight, 41 out of the 50 Dreamliners in operation around the world have now been grounded.
United Airlines -- the sole US carrier to fly the Dreamliner -- joined ANA and Japan Airlines (JAL) in withdrawing Dreamliners from service.
Air India and Chile's LAN Airlines followed suit, while LOT Polish Airlines -- the 787's only European operator for now -- was subject to a halt order from the European Union's aviation agency.
"We will track the FAA enquiry into the Dreamliner. We can't say when we will allow it to fly again, it depends on when Boeing gives us satisfaction over safety concerns," Arun Mishra, India's civil aviation chief, said.
The two airlines still operating 787s are Qatar Airways and Ethiopian Airlines. But the European Aviation Safety Agency stressed that the ruling from the FAA, in Boeing's home market, should apply to all the jets worldwide.
Japan is home to 24 Dreamliners and the government in Tokyo said it was taking no chances pending an investigation into whether the lithium-ion battery on the ANA flight had overheated.
Lithium-ion batteries are widely used in consumer electronics such as laptops and mobile phones. Airlines warn passengers against carrying too many in their baggage because of the risk of overheating.
The powerful lithium-ion batteries used on the Dreamliner have emerged as the focus of concern in light of the ANA incident and another on a JAL flight in the United States last week, with smoke reported on both planes.
Electrolyte leaks and burn marks were found on the battery's metal casing, ANA said. Kyodo News reported that officials from the Japan Transport Safety Board were working on the principle it overheated.
The batteries are made by Japanese firm GS Yuasa, one of a host of contractors in a complex web of global outsourcing that contributed to years of delays before Boeing delivered its first 787 to ANA in 2011.
GS Yuasa -- whose share price took a beating to close down five percent in Tokyo on Thursday -- defended its reputation for quality and warned that there was no quick fix in the Boeing investigation.
"It is impossible to predict at this point how long it will take, in terms of days or weeks, because we must study the system and GS Yuasa is not the only player involved," a company spokeswoman told AFP.
GS Yuasa said it supplies its 787 batteries first to France's Thales Group, which then assembles an electrical system for shipping to Boeing.
ANA said the particular battery involved had been installed in October, ahead of the expected two-year replacement cycle, because there had been a fault with the last one.
"Liquid leaked through the (forward battery compartment) room floor to the inside of the outer wall of the aircraft," Kyodo quoted investigator Hideyo Kosugi as saying.
Boeing shares ended 3.4 per cent lower on Wall Street Wednesday, even before the FAA announcement, as analysts fretted over the impact of the crisis on its long-term health given how important the Dreamliner is to its strategy.