Boeing on Monday began installing reinforced lithium ion batteries on five grounded 787 jets owned by launch customer All Nippon Airways, starting a process that should make the first commercial Dreamliners ready to fly again in about a week.

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Teams of Boeing engineers are working at four airports in Japan, including Tokyo's Haneda and Narita hubs, where the Dreamliners have been parked since regulators in the United States and elsewhere ordered all 50 planes out of the skies in mid-January after batteries on two of them overheated.

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Owning 17 of those aircraft, ANA is the world's biggest operator of the carbon-composite aircraft. After ANA, the biggest 787 operator is local rival Japan Airlines with seven jets, followed by United Continental United Airlines and Air India with six each.