The U.S. Federal Aviation Administration (FAA) on Sunday said it had investigated Leon’s safety complaints in 2008 and 2009 but concluded his allegations focused on prototypes that were not ultimately used in the new lightweight airliner.

FAA spokeswoman Laura Brown said the reviews also found that Securaplane’s production of a particular printed circuit board complied with FAA requirements.

Japan’s GS Yuasa Corp makes lithium-ion batteries for the Dreamliner, while France’s Thales produces the control systems for the battery. Thales has declined comment.

In its statement, the NTSB said French authorities were also participating in the investigation. No comment was immediately available from the French safety agency.

JAPANESE INVESTIGATION GEARING UP

Japan Transport Safety Board said it was aware of the NTSB report and would consider the U.S. statement in its probe.

The NTSB said the Japanese agency was participating in its investigation of the Boston incident, while NTSB officials were helping the agency with its investigation of the emergency landing in Japan. Both investigations were ongoing.

“There’s nothing more I can add at this point as we still haven’t started our investigation into the battery here,” JTSB inspector Hideyo Kosugi told Reuters. “The NTSB’s investigation started earlier. We still haven’t taken X-rays or CT-scans of the battery.”

Kosugi said both the battery and the surrounding systems were being stored in Tokyo’s Haneda Airport until authorities decided where to conduct the Japanese investigation.