Aviation safety officials from the U.S. and Japan on Monday visited the GS Yuasa Corp., in Kyoto, which manufactured the lithium-ion batteries for the 787 that led to the fleet's grounding last week. The investigators toured the plant and were briefed by company officials about the design, production and quality, according to Reuters. The U.S. investigators said they have ruled out excess voltage as a cause of the battery fire in Boston on Jan. 7, and will expand their probe to look at the battery charger and the 787's auxiliary power unit. Meanwhile, the NTSB plans to continue tests of the batteries this week in Arizona.
In Washington, Transportation Secretary Ray LaHood said the 787 won't fly again until regulators are "1,000 percent sure" that it's safe. Lithium batteries are used on other aircraft, according to Reuters, including some Airbus and Embraer models, but they are not from the same manufacturer used by Boeing.