Aerospace giant Boeing has sought Federal Aviation Administration permission to carry out test flights on the grounded Dreamliner 787.

All 50 of the aircraft presently in service with airlines around the world are grounded due to an ongoing investigation into battery problems.

A battery on a Japan Airlines 787 caught fire last month, while a malfunction forced an All Nippon Airways flight to make an emergency landing.

However, analysts have suggested Boeing may have identified the problem and gone some way toward rectifying it.

Test flights will allow the American company to test any progress.

The JAL and All Nippon Airways incidents prompted authorities in both the US and Japan to launch inquiries to try to find out what caused the battery problems.

However, transport ministry officials in Japan have since confirmed that safety inspectors had found no faults with the battery.

At the same time, Boeing, which launched its own investigation into the issue, also defended the battery being used on the plane.