"The leading experts in this field are working to understand what happened and how we can safely get these aircraft back into service," the statement read. "The FAA is looking at both the certification process and, specifically, at the required tests and design of the aircraft's lithium ion battery. The FAA invited the NTSB to observe this FAA-led process."
Just last night, the FAA announced it would allow a test flight of the Dreamliner from Texas to Washington state. The aircraft has special requirements for checking the battery throughout flight and only necessary personnel are allowed on board
United Airlines, the only U.S. operator previously flying the Boeing, announced last night that it will replace its six 787s with other planes through the end of February. The company still has plans, however, to start new flights with the aircraft at the end of March.
Despite the grounding and battery uncertainties, Boeing announced this afternoon that American Airlines ordered 42 new 787s this week.
Japan's All Nippon Airways on Wednesday canceled its 787 from flying through March 30.
The NTSB will be issuing an interim report on its investigation in a few weeks. The decision to return the 787 to flight will be made by FAA.
The Associated Press contributed to this report.