The Boeing 787 Dreamliner's lithium batteries caught fire — and the fleet was grounded

In January 2013, two Boeing 787 Dreamliners experienced lithium-ion battery fires within two weeks of each other — one in Boston and one in Japan. The fires were caused by thermal runaway in the batteries, a phenomenon where a cell overheats and triggers a chain reaction in adjacent cells.

The FAA grounded the entire 787 fleet — the first grounding of a new aircraft type in decades. Boeing spent three months redesigning the battery system, adding containment and venting features, before the fleet was cleared to fly again.

The investigation found that the battery design did not adequately account for the risk of thermal runaway, and that the certification process had not required sufficient testing for this failure mode. The case illustrated how a new technology (lithium-ion batteries in aviation) can introduce failure modes that the existing certification standards do not anticipate, and how the rush to be first with a new technology can outpace the safety analysis.