Pilots of the Ethiopian Airlines flight that crashed last month initially followed emergency procedures established by Boeing to manually disable the aircraft's automated anti-stall system, according to news reports on Wednesday, but the plane slammed into the ground about five minutes after takeoff killing all on board.

The flight crew turned off the Maneuvering Characteristics Augmentation System (MCAS) but they were unable to regain control of the MAX 8 jet and gain altitude, The Wall Street Journal reported, citing unnamed people it said had knowledge of the investigation.

After turning off the automated system but not controlling the plane, the flight crew re-engaged MCAS, according to the Journal. It's not clear why the pilots returned to the anti-stall system rather than continuing to follow Boeing's emergency checklist, the newspaper said. Using nonstandard procedures may have made the situation worse, aviation analysts who asked not to be identified by name told China Daily.

The action taken prior to the crash is still being evaluated by investigators attempting to determine the cause of the crash. Information contained in the plane's "black box" flight data recorder has not yet been officially released, but Reuters, without citing its source, reported on Wednesday that the MCAS system was engaged at least three times.

Action by the pilots in the minutes prior to the crash may call into question statements by Boeing and the US Federal Aviation Administration (FAA) that simply turning off the automated anti-stall system could have prevented the crash.

"We urge caution against speculating and drawing conclusions on the findings prior to the release of the flight data and the preliminary report," Paul Bergman, a spokesman for Boeing in Seattle, said in a statement.

James Hall, managing partner of Hall & Associates in Washington and former chairman of the National Transportation Safety Board, offered a similar view.

"Until the investigation is completed, it's too early to draw conclusions," Hall told China Daily USA. "We can't draw any conclusions from the flight crew's action."

John Cochran Jr, president and CEO of Eaglemark, an aviation consulting firm and professor emeritus of aerospace engineering at Auburn University, said the Ethiopian Airlines pilots may have lacked sufficient training in emergency procedures.

"There will be differences in training among different airlines," Cochran told China Daily. "You have to question the training if the pilots were looking at the manual to determine what to do. But it's still too early in the investigation to draw any definitive conclusions."

The Ethiopian Airlines flight crashed March 10, killing all 157 passengers and crew. Lion Air crashed in Indonesia Oct 29, 2018, killing all 187 people on board. Both planes maneuvered erratically shortly after takeoff.

After the second crash, 42 nations worldwide, including China, grounded the aircraft. The US was the last major country to order the planes grounded. Those nations had flown the 737 MAX, introduced in 2017, without incident.

The crashes raised questions about the automated anti-stall system. Boeing is cooperating with the investigation and is eager to determine the cause of the crash and resolve the issue, assuming the planes did not crash due to pilot error.

The Ethiopian Airlines flight crew did not train on a simulator before flying the MAX jet, The New York Times reported. Use of a simulator is generally considered essential training before piloting a new type of aircraft, including the 737 MAX, an updated version of prior Boeing aircraft.

Some analysts fault Boeing for not issuing explicit instructions on how to turn off the anti-stall device. Pilots said they first learned of potential difficulties with the new system after the Lion Air crash.

The FAA then ordered 737 MAX manuals to be updated and Boeing issued instructions telling pilots how to override the system. But pilots said Boeing failed to issue the instructions in a timely fashion and therefore independently compiled a 13-page guide for the 737 MAX.

There also may be a problem with the software that drives the anti-stall device, according to initial assessments of the crash. The software updates follow preliminary results from the Lion Air crash that suggested bad data from a single sensor may have caused the anti-stall system to malfunction and send the plane into the fatal dive.