TOKYO -- Boeing said Friday it sees commercial flights of its grounded 787 jets resuming "within weeks" even though it has not pinpointed the cause of battery overheating.
Boeing Co. Chief Project Engineer Michael Sinnett outlined a fix centered on a new design for the lithium-ion battery system that has many layers of safeguards to prevent overheating. It also has measures to contain any problems if malfunctions do occur.
"We could be back up and going in weeks and not months," Sinnett told reporters at a Tokyo hotel.
The 787 fleet was grounded worldwide by the U.S. Federal Aviation Administration, its counterparts in Japan and other nations in January, following a battery fire in a Dreamliner parked in Boston and an overheated battery that led to an emergency landing of another 787 in Japan.
All Nippon Airways, a major Japanese carrier, was the launch customer for the technologically advanced Dreamliner planes. With Japan Airlines another customer, about half the 787 jets in use were with Japanese carriers.
The Boeing executives sought to allay flier fears about the 787 by repeatedly stressing their commitment to safety.
They said it would take too long to figure out what had specifically caused the problems in Boston and southwestern Japan but the new design would ensure 787s are safe.
Boeing came up with 80 possible causes for the battery problems, categorized them into four groups, and came up with design adjustments such as better insulation between each battery cell so any malfunctions won't spread. That was to allow the 787 to be back in the air more promptly, they said.
There were also changes to wiring for the battery, aimed at preventing overheating, and a new enclosure for the battery that would eliminate fire risk.
While executives acknowledged that final approval would have to come from the FAA, and didn't rule out further delays to ensure safety, they said they were in close contact with the FAA and didn't foresee any long delays.
"It's a safe airplane. We have no concerns at all about that," Sinnett said.
Boeing Executive Vice President Ray Conner also offered his apologies to the Japanese people for the problems.
"We do apologize for this situation," Conner said. He said he was in Japan to meet with aviation authorities and airlines, and the company had picked Japan as the place to outline the battery fix.