Boeing has dispatched maintenance teams to Japan, where they are standing by to retrofit a new battery containment system on the grounded 787 aircraft of All Nippon Airways (ANA) and Japan Airlines (JAL).
When the new containment system is certified by the US Federal Aviation Administration and the Japan Civil Aviation Bureau, the teams can commence retrofitting the aircraft, says a Boeing spokesman.
He did not provide details about the number of Boeing personnel involved, or how many aircraft will receive the battery containment retrofit simultaneously. Each retrofit is likely to take four to five days, he adds.
An ANA spokeswoman says the carrier is aware of the Boeing teams' presence in the country, but that the teams have "not touched the aircraft yet".
The new battery containment system for the 787 aims to reduce the risk of the aircraft's lithium-ion batteries overheating, and to eliminate the risk of the batteries starting a fire.
The global 787 fleet has been grounded since mid-January, when an ANA 787 made an emergency landing because of a battery-related problem. This came just days after a 787 operated by JAL suffered a fire in its rear battery compartment while on the ground at Boston Logan International Airport.
ANA is offering domestic 787 tickets from 1 June, and plans to conduct simulator training for 787 pilots in April to prepare for the type's eventual return to service.
The carrier has given no indication as to when it believes the 787 grounding could be lifted.
Boeing officials have expressed confidence that the airframer's proposed 787 battery fix will receive regulatory approval, allowing the aircraft to recommence operations.
ANA and JAL are the world's largest operators of the 787. According to Flightglobal Pro data, ANA has received 17 787-8s. It has an additional 19 787-8s on order, as well as 30 787-9s.
JAL has received seven 787-8s, with 18 yet to be delivered. It has also ordered 20 787-9s.