The agency grounded the 787 after a fire broke out on a 787 operated by Japan Airlines at Boston's Logan International Airport. The fire was caused by a lithium-ion battery failure.
Smoke was seen in-flight on another 787 that had a similar battery issue shortly thereafter, causing the FAA to order U.S. airlines to take the planes out of service.
The second plane, operated by Japanese airline All Nippon Airways, made an emergency landing. No one was hurt in either incident, but other worldwide aviation agencies followed the FAA's lead, resulting in a worldwide grounding of the Dreamliner.
The National Transportation Safety Board (NTSB) has said that the 787 battery that caught fire in Boston exhibited signs of accelerated temperature increases known as "thermal runaway" and short-circuiting.
The NTSB is conducting a separate review of the 787's battery issues.