Federal regulators have approved a Boeing plan to redesign the 787 Dreamliner's fire-prone lithium-ion batteries, although extensive testing will be needed before the planes can fly passengers again.

The Federal Aviation Administration said Tuesday the plan includes a redesign of the internal battery components to minimize the possibility of short-circuiting, better insulation of the battery's eight cells and the addition of a new containment and venting system.

The FAA says the battery certification plan requires a series of tests, including flight tests, which must be passed before the 787 can return to service.

The 787 fleet worldwide has been grounded since Jan. 16, following a battery fire on a Dreamliner parked in Boston and a smoking battery that led to emergency landing by other another 787 in Japan.