Federal officials have accepted Boeing’s revamped battery system for its beleaguered 787 Dreamliners and intend to lift a 3-month-old order grounding the planes.

The Federal Aviation Administration said in a statement Friday that next week it will send airlines instructions and publish a notice lifting the grounding order. The lifting of the grounding order will be effective the day the notice is published.

Lifting the grounding order gives Boeing the go-ahead to begin retrofitting planes with an enhanced lithium ion battery system. The root cause of battery failures that led to a fire on one of the planes and smoke on another remains unknown.

Flights could resume within a week.

Boeing assembles the 787 at plants in North Charleston and Everett, Wash. The grounding had not discernible impact on operations at the factories.

“FAA approval clears the way for us and the airlines to begin the process of returning the 787 to flight with continued confidence in the safety and reliability of this game-changing new airplane,” said Boeing CEO Jim McNerney. “The promise of the 787 and the benefits it provides to airlines and their passengers remain fully intact as we take this important step forward with our customers and program partners.”

Approval of the improved 787 battery system was granted by the FAA after the agency conducted a review of certification tests.

“The tests were designed to validate that individual components of the battery, as well as its integration with the charging system and a new enclosure, all performed as expected during normal operation and under failure conditions,” Boeing said.

Testing was conducted under the supervision of the FAA over a month-long period beginning in early March.

“The FAA set a high bar for our team and our solution,” said McNerney. “We appreciate the diligence, expertise and professionalism of the FAA’s technical team and the leadership of FAA Administrator Michael Huerta and Secretary of Transportation Ray LaHood throughout this process. Our shared commitment with global regulators and our customers to safe, efficient and reliable airplanes has helped make air travel the safest form of transportation in the world today.”

Check back at postandcourier.com later or see Saturday’s editions of The Post and Courier for more details.