Japan Airlines' (JAL) fleet of Boeing 787-8s have completed modifications and is on track to resume operations on 1 June.
Aircraft JA826J was the seventh and last aircraft to receive modifications to its lithium-ion batteries, including the installation of a new containment system. The works were finished on 13 May.
Four of JAL's seven 787s have also completed confirmation flights, where no battery problems were found, says the carrier.
Fellow Japanese carrier All Nippon Airways (ANA) still has six 787s undergoing modifications. Works on 11 others have been completed, where like JAL, the carrier did not discover any further problems.
JAL and ANA have also been conducting familiarisation flights with its pilots on the aircraft type since 4 May and 28 April respectively.
Both carriers, which together own about half of the worldwide fleet of 787s, have said that they plan to resume 787 operations on 1 June.
ANA will deploy the aircraft type on routes from Tokyo Narita to San Jose, and from Tokyo Haneda to Frankfurt and Beijing.
JAL meanwhile will use the 787s on services from Tokyo Narita to Boston, San Diego and Singapore, and also on routes from Tokyo Haneda to Singapore and Beijing.
Flightglobal Pro data shows that ANA has received 17 787-8s, with an additional 19 -8s and 30 787-9s on order. JAL, meanwhile, has seven -8s in its fleet, with an additional 18 -8s and 20 787-9s on order.