The Federal Aviation Administration, or FAA, has approved the Boeing Company (NYSE:BA) battery design modifications for its 787 Dreamliner, thus ending the three-month worldwide grounding of the model, the longest FAA grounding on record.

The FAA announced Friday that it cleared Boeing's changes to its lithium ion battery designs across all of its carriers' existing 787 models. Boeing addressed risks at the battery cell level, the battery level and at the aircraft level. With the FAA's green light, the aviation giant will return them to regular service over the next several weeks.

The next big steps will begin with the FAA issuing instructions to commercial carrier technicians about exactly how to institute the safe batteries in their aircraft. Carriers must install containment and venting systems for the main and auxiliary system batteries and replace battery chargers with modified components. Return to service of the modified 787 will only take place after the FAA inspects the work.

"Safety of the traveling public is our No. 1 priority. These changes to the 787 battery will ensure the safety of the aircraft and its passengers," Transportation Secretary Ray LaHood said.

"A team of FAA certification specialists observed rigorous tests we required Boeing to perform and devoted weeks to reviewing detailed analysis of the design changes to reach this decision," FAA Administrator Michael Huerta said.

Boeing was never able to replicate the accidents that caused a Japan Airlines Co. (9201) 787 plane to catch fire in Boston on Jan. 7 and also forced an ANA Holdings Inc. (9202) jet to make an emergency landing in Japan Jan. 16.