Boeing has said a flight to test the new batteries on the Dreamliner “went to plan”.

All 50 Dreamliners in operation have been grounded and orders delayed following a fire in a battery on a Japan Airlines 787 in Boston on January 7 and an emergency landing by an All Nippon Airways aircraft in Japan shortly afterwards when a battery started producing smoke.

A 787 took off at 12:11pm Pacific Time from the airfield at Boeing’s main production plant in Everett, Washington, for the “functional test flight” and returned two hours later.

The aircraft was the first to be fitted with lithium-ion batteries designed to reduce the risk of overheating.

Boeing said it would assess the data and prepare for another test flight to reassure regulators.

The battery redesign plan was approved by the US Federal Aviation Administration (FAA) earlier this month.

US transportation secretary Ray LaHood said at the time: “This comprehensive series of tests will show us whether the proposed battery improvements will work as designed.”

But he added: “We won’t allow the plane to return to service unless we’re satisfied that the new design ensures the safety of the aircraft and its passengers.”