Accident investigators are recommending the U.S. government require air shipments of rechargeable batteries be separated from other flammable cargo to prevent uncontrollable fires that can destroy planes.
The National Transportation Safety Board said its recommendation is based on an investigation by South Korean authorities of the destruction of an Asiana Airlines cargo plane in July 2011.
NTSB Chairman Chris Hart said in a letter to the Pipeline and Hazardous Materials Safety Administration that a fire on board the plane developed on or near two pallets, one containing lithium-ion batteries for hybrid-electric cars and the other with flammable liquids. The source of the fire couldn't be determined.
Seventeen minutes after the pilots reported the fire, the Boeing 747 broke up over the ocean despite desperate efforts to reach a place to land.
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