NEW : Japanese authorities say they experienced a sudden drop in voltage . U.S. government officials evaluating data as part of investigation of the problems . Aircraft were grounded last week after incidents in Tokyo , another incident in Japan . Additional details released by the safety board said all eight cells of the lithium-ion battery involved in the Boston 787 fire showed varying degrees of thermal damage . Fifty Dreamliners in service globally , but Boeing has orders for several hundred .
NEW : Japanese authorities say they experienced a sudden drop in voltage . U.S. government officials evaluating data as part of investigation of the problems . Aircraft were grounded last week after incidents in Tokyo , another incident in Japan . Fifty Dreamliners in service globally , but Boeing has orders for several hundred .