TOKYO (AFP) - Japan's transport minister said Tuesday he had ordered the country's two biggest airlines to inspect their entire modified Dreamliner fleets after a fault was found with one aircraft at the weekend.
Minister Akihiro Ota said he issued the instruction to Japan Airlines (JAL) and All Nippon Airways (ANA) after JAL found a fault with an air pressure sensor in the Dreamliner's battery container on Sunday.
The setback, although not serious, is yet another embarrassment for Boeing, which admitted in April that despite months of testing it did not know the root cause of problems that had led to the worldwide grounding of the next-generation airliner.
The grounding order was issued in January after lithium-ion batteries overheated on two different planes, with one of them catching fire while the aircraft was parked.
Both airlines began regular flights with their 787 fleets on Saturday, but following the discovery of the fault on Sunday, JAL was forced to use a substitute aircraft.
The firm said the sensor in the battery container showed a difference in air pressure between inside and outside during a pre-departure safety check.
The difference came after small holes on the container - necessary for ventilation to prevent overheating - were mistakenly sealed when earlier modifications were carried out.
"It was regrettable that the modification operation was not fully done," Mr Ota said, according to a ministry official. "(The trouble) did not affect flight safety but it is true that it worried passengers."
A spokesman for JAL said inspections had been carried out without delay.
"We finished checking the part on all the planes (787s) on Sunday. There is no impact on our operation of the aircraft," he said.
No one from ANA was immediately available for comment.