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. Government personnel involved in flight tests knew about changes Boeing made to the flight-control system, but engineers responsible for certifying the plane did not, according to the report, which is expected to be released Wednesday. Engineers for the Federal Aviation Administration didn’t perform a detailed examination of the flight-control system, called MCAS, until after the first crash, in October 2018 off the coast of Indonesia. In that crash and another less than five months later in Ethiopia, MCAS pushed the nose of each plane down and pilots were unable to regain control.