The Japanese authorities said on Wednesday that they will conduct an analysis of a battery for the auxiliary power unit used in Boeing Company’s 787 Dreamliner that made an emergency landing in Western Japan last week.

It comes after an All Nippon Airways (ANA) 787 had to make an emergency landing due to a battery malfunction.

Japanese and US transport authorities are currently looking into the main battery of the ANA plane that caught fire.

The battery for the auxiliary power unit was intact, but the safety board decided to review the two batteries — both made by GS Yuasa Corp.

An electrical fire that caused smoke in the cabin of another Dreamliner jet operated by Japan Airlines Company in Boston earlier this month originated from a battery for the auxiliary power unit.

Analysis of the main battery of the ANA jet continued on Wednesday at a Tokyo facility of the Japan Aerospace Exploration Agency.

Following a CT scan of the charred battery, it will be sent to GS Yuasa for detailed scrutiny, the safety board said.

Together with inspectors of the US National Transportation Safety Board, officials of Thales SA, a French military aircraft builder that designed the 787’s electrical system, also observed the analysis at the request of French aviation safety authorities.