An investigation into the battery that caught fire aboard an empty Japan Airlines Boeing 787 in Boston this month has found it was not overcharged.

The National Transportation Safety Board (NTSB) said the battery did not exceed its designed voltage of 32 volts.

The group is continuing to examine the battery system and will meet Tuesday with officials from Securaplane Technologies Inc., the manufacturer for the 787s lithium ion batteries, at the company's headquarters in Tucson, Arizona.

"The team has developed test plans for the various components removed from the aircraft, including the battery management unit (for the APU battery), the APU controller, the battery charger and the start power unit," NTSB said in a statement.

While the voltage limit was not exceeded in the Japan Airlines plane, it is still possible the battery failures in the aircraft may be due to a charging problem, NTSB said.

If there is too much current flowing too fast into a battery, it can cause it to short-circuit and overheat even if its voltage remains within its design limit, according to the board.

Last week the Federal Aviation Authority announced a comprehensive review of the 787's critical systems and the aircraft's design, manufacture an assembly.

The Japan Transport Safety Board and French Bureau d'Enquêtes et d'Analyses pour la sécurité de l'aviation civile have also appointed accredited representatives to the investigation.

The Japan Airlines plane caught fire January 7th while it was sitting on the tarmac at Boston's Logan Airport.

In another incident an All Nippon Airways made an emergency landing in Japan last week after battery problems and a burning smell was detected in the cockpit and cabin.

All 50 of 787 Boeing planes delivered to airlines have since been grounded. The manufacturer has halted deliveries of new planes until it addresses the electrical problem.

RD

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