Nearly four months after grounding the Dreamliner because its battery exploded into flames on the tarmac in Boston, the FAA has cleared the maligned Boeing 787 for commercial flights. The plane will be permitted to fly up to 180 minutes from its point of departure—the same clearance it had before.
Next week the FAA publish instructions for the modifications operators will need to make to the planes out there so that they're safe for flight. According to the release by the FAA, the flight ban won't be lifted until those instructions are published. There's no timeline on when there might be planes up in the air again.
Boeing introduced several design changes to the Dreamliner's unique lithium-ion battery following an extensive NTSB investigation into the Boston incident. Both the company and the FAA were blasted for failing to ensure that the battery was fully tested before commercial flights began. Boeing completed the required certification testing for the battery system a few weeks ago, Most people have been expecting the FAA rubber stamp since then.
Next week, the NTSB will conduct two days of hearings on the Dreamliner battery. The root cause of the failure isn't known, but the battery has been altered down to the "cell level" to prevent future issues. Hopefully everything has been adequately tested so that the plane is safe. [FAA]
According to Boeing reps during a press briefing shortly after the FAA announcement, the new battery system does much better when it's driven to failure by applying large amounts of energy with a heating element. Indeed, this data suggests difference in battery performance is significant: