No faults have been found in the battery used on Boeing's 787 Dreamliner after inspection by airline safety inspectors, according to Japan's transport ministry.
The battery was initially suspected to be the likely source of problems on 787s owned by two Japanese airlines, which had raised fears that there would be no quick fix to the problem, rasing the prospect of grounding of all 50 787s in service.
Attention would now focus on the electrical system that monitors battery voltage, charging and temperature.
According to transport ministry officials no major quality or technical problem had been found with the lithium-ion batteries. Shares in GS Yuasa, which makes the batteries, surged 5 per cent on the news.
Officials added that the ministry was looking into affiliated parts makers and into possibilities.
The safety investigation got under way after one of the 787s operated by All Nippon Airways made an emergency landing in Japan following the overheating of its main battery. In a similar incident earlier, a battery in a Japan Airlines 787 caught fire at Boston's Logan International Airport.