Boeing has said that a test flight to check the 787 Dreamliner's redesigned battery system “went according to plan”.

Its entire 787 fleet has been grounded since January, after a battery on one plane caught fire in Boston and the battery on another began smoking during a flight in Japan, forcing an emergency landing.

The firm said it will analyse the data and prepare for another test flight aimed at demonstrating the system to regulators in “coming days”.

It is estimated that the two-month worldwide grounding of the high-tech jet is losing Boeing $50 million per week.

It has also prevented the company from delivering new Dreamliners to customers.