Airline safety inspectors have found no faults with the battery used on Boeing’s 787 Dreamliner, Japan’s transport ministry has announced.
Dreamliner’s battery was initially considered the likely source of problems on 787s owned by two Japanese airlines.
The world’s entire fleet of 50 787s has been grounded while inspections are carried out.
Attention has now shifted to the electrical system that monitors battery voltage, charging and temperature.
Transport ministry official Shigeru Takano said “we have found no major quality or technical problem” with the lithium-ion batteries. Shares in GS Yuasa, which makes the batteries, jumped 5% on the news.
“We are looking into affiliated parts makers,” he said.
“We are looking into possibilities.”
Airline safety inspectors have found no faults with the battery used on Boeing’s 787 Dreamliner
The safety investigation started after one of the 787s operated by All Nippon Airways made an emergency landing in Japan when its main battery overheated. Earlier, a battery in a Japan Airlines 787 caught fire while parked at Boston’s Logan International Airport.
Two weeks ago the US Federal Aviation Administration said both batteries had leaked electrolyte fluid, and there had been smoke damage to parts of the aircraft.
The FAA said airlines must demonstrate battery safety before flights could resume, a statement that effectively meant airlines had to ground their 787s.
Boeing, which competes against Europe’s Airbus, has halted 787 deliveries. Boeing has orders for more than 800 Dreamliners.
The 787 is the first airliner made mostly from lightweight composite materials that boost fuel efficiency. It also relies on electronic systems rather than hydraulic or mechanical systems to a greater degree than any other airliner.
Boeing has decided to suspend deliveries of its new 787 Dreamliner jet until a battery problem is resolved.
Boeing said it would continue to build the plane, but not deliver any until US safety officials gave their backing.
The Federal Aviation Administration has joined the Dreamliner investigation.
All 50 of Boeing’s 787 Dreamliners have been suspended from flying since an All Nippon Airways flight on Wednesday made an emergency landing due to a fault.
“We will not deliver 787s until the FAA [Federal Aviation Administration] approves a means of compliance with their recent Airworthiness Directive concerning batteries and the approved approach has been implemented,” said a Boeing spokesman in an email.
US Transportation Secretary Ray LaHood said earlier the Dreamliner would not fly again under authorities were “1,000% sure” it is safe.
Boeing has decided to suspend deliveries of its new 787 Dreamliner jet until a battery problem is resolved
A string of issues in recent weeks has raised questions about the 787, which is the first major aircraft grounding since 1979.
Dreamliners have suffered incidents including fuel leaks, a cracked cockpit window, brake problems and an electrical fire. However, it is the battery problems that have caused the most concern.
This week, US and European aviation regulators said planes should be grounded while safety checks are carried out on their lithium ion batteries.
On Friday, US officials from the Federal Aviation Administration and the National Transportation Safety Board joined the Japanese probe at Takamatsu airport in western Japan.
The Japan Transport Safety Board said the battery and the systems around it would be sent to Tokyo for more checks, adding there were similarities with an earlier battery fire on a 787 in Boston operated by Japan Airlines.
The pilot of the ANA plane made an emergency landing on Wednesday after he smelled burning and received a cockpit warning of battery problems. All passengers evacuated the plane on emergency slides.
The investigation is being led by the Japan Transport Safety Board.
Boeing and European rival Airbus dominate the global airliner market.
Two fresh setbacks have hit Boeing’s 787 Dreamliner plane, two days after an electrical fire broke out on board a Japan Airlines Dreamliner on Monday.
In the latest incident, Japan’s All Nippon Airways cancelled a domestic 787 flight from Yamaguchi to Tokyo on Wednesday because of a brake problem.
On Tuesday, Japan Airlines cancelled a Boston to Tokyo flight after about 40 gallons (151 litres) of fuel spilled.
Passengers got off safely and no-one was hurt, an airport spokesman said.
A spokeswoman for Japan Airlines, Carol Anderson, said on Tuesday that the second Dreamliner had returned to the gate because of mechanical issues and details were not yet confirmed, Reuters reported.
Meanwhile, the US National Transportation Safety Board said that it would not investigate Tuesday’s incident, because there had not been an accident.
Two fresh setbacks have hit Boeing’s 787 Dreamliner plane, two days after an electrical fire broke out on board a Japan Airlines Dreamliner on Monday
ANA was the first company to take delivery of a Dreamliner and started providing flights on the aircraft in October 2011.
On Monday, a fire broke out in a Dreamliner operated by Japan Airlines soon after it landed in Boston from Tokyo.
The fire started after a battery in the jet’s auxiliary power system overheated.
Nobody was hurt as passengers and crew had already disembarked.
The Dreamliner is one of the most advanced planes ever built. However, a spate of technical issues has hurt its image.
Last year, a United Airlines flight was forced to make an emergency landing because of an electrical problem.
In December, Qatar Airways grounded one of its 787 Dreamliners after several manufacturing faults caused electrical problems similar to those that affected the United plane.
To add to Boeing’s woes, the US Federal Aviation Administration said in December that it had identified errors in the assembly of fuel line couplings in the Dreamliner.
It warned that these errors could result in fuel leaking on to hot engine parts and start a fire, cause engine failure, or simply see the plane run out of fuel.
Analysts said the latest incident on the Japan Airlines flight was a blow to Boeing.
“Even though it happened on the ground, rest assured the FAA is asking, <<What if it happened in the air?>>,” Carter Leake, an analyst at BB&T Capital Markets in Virginia.