Boeing Dreamliner fire cause 'unknown', says US
7 March 2013 Last updated at 17:42 GMT
The US national transportation board has released an interim report into a battery fire aboard a Japan Airlines Dreamliner on 7 January.
It says it still has not discovered the cause of the fire.
Boeing's entire fleet of Dreamliners was grounded after a battery on a Japan Airlines 787 caught fire, and a malfunction forced an ANA flight to make an emergency landing.
Samira Hussein reports.