Boeing says a more robust “abuse” test that it performed on the upgraded 787 lithium-ion batteries satisfies the safety conditions issued by the FAA during the initial certification of the aircraft. Speaking at the NTSB’s two-day investigative hearing into the Jan. 7 battery failure on a Japan Airlines 787 at Boston Logan International Airport, Boeing systems engineer Jerry Hulm said the company developed a method for simulating internal short circuits in the battery by “injecting heat” into a cell to force a short circuit and cell thermal runaway. Though the NTSB has yet to determine the root cause of the Boston incident, it has determined that there was a short circuit in a cell and propagation of thermal runaway to other cells.