Boeing has applied to the US Federal Aviation Administration to conduct test flights on its grounded 787 aircraft.

"We have submitted an application to conduct 787 test flights and it is currently under evaluation by the FAA," says a spokesman.

The fleet of 787s worldwide has been grounded since 16 January after the FAA issued a directive following an incident where an All Nippon Airways' 787 had to make an emergency landing because of a battery-related problem. Transport ministries worldwide then issued similar directives to ground the aircraft type.

The incident on ANA's 787 and an earlier battery fire on a Japan Airlines 787 raised safety concerns about the lithium-ion batteries that the aircraft use.

The National Transport Safety Board's investigation has so far offered no further clues about the root cause behind the 787 battery failures, even as the 787s remain grounded for over two weeks.

Source: Air Transport Intelligence news