Testing of the 737 Max jetliner’s revised flight-control systems by U.S. regulators and Boeing Co. wrapped up July 1, laying the foundation for the plane’s possible return to service later this year.

A government report says Boeing did not give regulators documents about changes it made in a key system blamed in two deadly crashes of its 737 Max jet, and that officials responsible for approving the plane did not know how powerfully the system could push the plane’s nose down.

A Boeing 777 made for FedEx Express will be the latest in the aircraft manufacturer’s ecoDemonstrator series of planes designed to test emerging technologies.