Pilots of the 737 Max that crashed in Ethiopia in March initially followed Boeing’s standard emergency procedures to try to get control of the plane, but ultimately failed, The Wall Street Journal reported Wednesday.

Crew members turned off the flight-control system that automatically pushed down the plane’s nose after takeoff but could not get the plane to climb, the Journal reported, citing people briefed on the investigation’s preliminary findings. The Ethiopian Airlines crew ended up turning the control system back on before the plane crashed, killing all 157 people aboard.

It’s the latest report amid mounting pressure on Boeing and the Federal Aviation Administration over their assertions that the crash may have been avoided had pilots simply followed established safety procedures. The new details of the crash are based on data from the aircraft’s "black box" recorders.

The pilots turned the electrical power back on, which re-engaged the stall-prevention feature, known as MCAS, and then used electrical switches to try to raise the nose, the Journal’s sources said.

It’s not clear why pilots on Ethiopian Flight 302 turned the automated system back on rather than continuing to follow Boeing’s standard emergency steps. Government officials and investigators said it’s likely that manual controls to raise the nose of the plane didn’t work, and pilots tried to reengage the system to combat the nose-down angle of the jet and failed, the Journal reported.

The same Maneuvering Characteristics Augmentation System was also involved in the 737 Max crash in Indonesia in October that resulted in deaths of all 189 people on board.

The Senate Committee on Commerce, Science and Transportation launched an investigation on Tuesday into whistleblower complaints accusing the FAA of improperly training its safety inspectors to review the Boeing jets. The FAA may have been notified about these deficiencies as early as August, the panel said. The Justice Department has also launched a criminal probe.

Ethiopian investigators are expected to release a preliminary report about the crash in coming days. Investigators looking to the Lion Air Flight 610 crash in Indonesia think similar system malfunctions were involved, including erroneous data from a single sensor that caused the MCAS system to misfire.

Boeing is still preparing software updates for the 737 Max plane’s flight-control system. The plane maker initially planned to submit the fixes to the FAA last week but said it needs more time. The revised software will have two sensors, rather than one, and will give pilots more control over the system, according to Boeing.