SEATTLE -- Nearly nine months after it returned to the sky and its battery system was declared safe, new reports surfaced Tuesday of smoke aboard a Boeing 787 Dreamliner at Tokyo's Narita International Airport.
The incident "appears to have involved the venting of a single battery cell," aboard a Japan Airlines 787, Boeing told CNN in a statement. A year ago, overheated batteries aboard two Dreamliners prompted aviation officials to ground all 50 of the planes worldwide.
Tuesday's incident "occurred during scheduled maintenance activities with no passengers on board," the Boeing statement said. "The improvements made to the 787 battery system last year appear to have worked as designed." Boeing said it was working with Japan Airlines to return the plane to service.
Boeing's stake in the Dreamliner is huge. Hundreds of millions of dollars are riding on the success of the 787, which represents a new generation of lighter, more efficient money making planes.
When it began service in 2011, the Dreamliner boasted a new battery system that used new, lighter lithium-ion batteries. After the planes were grounded, Boeing and the Federal Aviation Administration collaborated on a new battery compartment. The compartment was designed to insulate the batteries in a ventilated armor-plated box to protect the rest of the plane in case of a fire caused by overheating batteries. The NTSB announced this month it plans to issue a final investigation report later this fall.
U.S. aviation investigators -- the National Transportation Safety Board -- told CNN it is aware of Tuesday's battery incident in Japan. A spokesman said the Japanese Transportation Safety Board "is determining whether they are going to open an investigation into it. If they do, we would be participating."
In July 2013, investigators blamed a fire aboard an empty Ethiopian Airlines 787 parked at London's Heathrow airport on a malfunctioning emergency beacon.
Tuesday's incident comes nearly two months after Boeing warned airlines about another 787 concern: possible icing problems in its GE engines.
The aircraft manufacturer alerted 787 operators after instances of "ice crystal icing that resulted in temporary diminished engine performance," Boeing said in a statement.
Although it said only a small number of the engines have experienced the ice problems, Boeing advised pilots to keep planes at least 50 nautical miles from storms that may contain ice crystals until General Electric can make improvements to the "GEnx" engines.
The Dreamliner's development was marked by production delays and other problems. Then, a year ago this month, batteries were blamed for two overheating instances on a Japan Airlines 787 in Boston and on an All Nippon Airways 787 in Japan. No one was hurt in either case, but concerns about the incidents spurred the FAA to ground all U.S. Dreamliners. Officials around the world followed suit.
Experts say every airliner experiences "teething pains" during its first few years of service, as minor problems are shaken out. But the FAA's decision to ground the Dreamliner put it under intense scrutiny.
United Airlines is the lone U.S. operator of Boeing 787s.
Last July, in an apparent show of confidence, United announced it was ordering 20 new 787-10 models, which are a longer version of the plane.