The power unit fault raises fresh concerns about safety and reliability after an earlier grounding of the entire fleet.
An overheating battery aboard a Boeing 787 Dreamliner causing the plane to be grounded reached temperatures capable of melting rock, it has emerged.
The heat generated by the faulty power unit, which poured out white smoke, hit a searing 660 degrees centigrade – the point at which minerals start to turn molten.
The startling figure was revealed in a report released by Japan’s transport ministry into the meltdown on a Japan Airlines aircraft undergoing maintenance at Tokyo’s Narita airport.
It was the latest in a series of problems to plague the aircraft.
According to the report, one of the eight lithium-ion cells in the plane’s battery system “swelled and electrolytic solution was sprayed (out)”.
An official said: “We estimate that temperatures inside the cell possibly reached 660 Celsius as the aluminium electrode melted.”
It is still not known what caused the battery to overheat, the official said, who added that the ministry would continue to investigate the case with Boeing.
Following the incident last month, the plane, which had been due to fly to Bangkok, was taken out of service, and the 158 passengers due to board the plane were put on a separate 787.
It came after the global 787 fleet was grounded by regulators last year after two batteries overheated, raising renewed concerns about the model’s safety and reliability.
All Dreamliners were taken out of action for more than three months while Boeing redesigned the battery, charger and containment system to ensure battery fires would not put the aircraft at risk.
Since then, the aircraft have experienced a series of minor glitches, including a fault with an air pressure sensor and the brake system.
Boeing insists the Dreamliner is operating safely.
Source : Sky News