"We do conclude that the aircraft is safe and that it meets its intended level of design and safety," FAA Administrator Michael Huerta said.
The FAA review of the design, manufacture and assembly of the 787 began Jan. 11, 2013, four days after a lithium battery fire aboard an empty Japan Airlines jet parked in Boston. Then an All Nippon Airways flight made an emergency landing in Japan on Jan. 16, 2013, because of a smoldering battery.
The review wasn't limited to the battery or electrical system, and, while the entire plane was deemed safe, Huerta didn't discuss the battery specifically because those incidents remain under investigation
The 71-page report that resulted from the review made seven recommendations for FAA and Boeing basically to focus their inspections and oversight more on higher-risk areas of a plane as it is developed. These areas are where less is known about the material or equipment, so there is not as much familiarity with how it will operate.
"We concluded that the aircraft was soundly designed, and that Boeing and the FAA had processes in place that were designed to identify and correct any issue that might arise during the manufacturing process," Huerta said. "It's many layered. You don't have single points of failure."
Boeing Commercial Airplanes CEO Ray Conner said the company has already taken significant steps to implement its recommendations, such as improving the flow of information, standards and expectations with suppliers.
"The findings validate our confidence in both the design of the airplane and the disciplined process used to identify and correct in-service issues as they arise," Conner said.
The FAA grounded the first six jets in the USA for more than three months, which led to a worldwide hiatus in flights for 49 planes.
Without knowing precisely what caused the problem, Boeing developed more insulation between each battery's cells and a fireproof shell for the battery to starve it of oxygen if there is a fire. The improvements were added before the plane returned to the skies.
Each jet carries two batteries, which are surrounded by a stainless steel box. Each battery has a titanium venting tube to a hole in the fuselage to carry flammable electrolytes and smoke overboard if a battery fails.
The National Transportation Safety Board continues to investigate the cause of the Boston fire. Another battery problem surfaced in January on a Japan Airlines jet parked in Tokyo, where Boeing discovered during routine maintenance that one cell of a battery released gas.
The Dreamliner is an innovative jet built largely from composite material, which makes it lighter and 20% more fuel-efficient. Passengers like the jet's quietness in flight and its larger windows equipped with electronic dimmers rather than shades.
Boeing delivered 65 of the jets last year and expects to deliver 110 this year. The company wants to sell 3,300 of the jets during the next 20 years.