TOKYO, May 16 (Reuters) - ANA Holdings Inc, the world’s biggest operator of Boeing Co’s 787 Dreamliner, reported an electrical panel fault during a test flight as it prepares its fleet for a return to service in June following a more than three-month grounding of the carbon-composite aircraft.
Engineers found discoloration on a connection on an electrical panel following a flight from Tokyo’s Haneda Airport to Sapporo on Japan’s northern island of Hokkaido on May 4, a spokesman for ANA said.
The panel, which was not part of the jetliners’ battery system, was changed and the plane returned to Tokyo. ANA blamed a loose nut for the cause of the problem, which it said did not compromise the safety of the aircraft.
The 787 Dreamliner was grounded worldwide in January after batteries overheated on jets owned by ANA and Japan Airlines Co Ltd. ANA, which took delivery of its latest Dreamliner on Tuesday, owns 18 of the jets, with JAL operating seven.
Investigators in the United States and Japan have yet to discover what caused the 787’s batteries to overheat.