The pilots of an Ethiopian Airlines 737 MAX jet that crashed last month had initially followed Boeing Co’s emergency procedures but later deviated from them as they tried to regain control of the plane, the Wall Street Journal said on Wednesday.

The crash killed all 157 people on board and led to a global grounding of 737 MAX jets and scrutiny of the certification process for the Boeing plane.

Boeing had issued guidelines to pilots on how to disable an automated anti-stall system after a deadly crash in Indonesia in October, that were followed by an emergency airworthiness directive by the US Federal Aviation Administration (FAA).

The Journal report, citing unidentified people briefed on the matter, said the pilots had initially shut off the MCAS anti-stall system that was pushing the aeroplane’s nose down shortly after it took off from Addis Ababa.

The pilots then cranked a manual wheel in an attempt to stabilise the plane, the report said, but they eventually decided to restore power to the usual electric trim on their control yokes, likely because the manual attempt did not achieve the desired results.

Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures Show all 9 1 /9 Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures This picture taken on March 11, 2019, shows debris of the crashed airplane of Ethiopia Airlines, near Bishoftu, a town some 60 kilometres southeast of Addis Ababa, Ethiopia. - An Ethiopian Airlines Boeing 737 crashed on March 10 morning en route from Addis Ababa to Nairobi with 149 passengers and eight crew believed to be on board, Ethiopian Airlines said. (Photo by Michael TEWELDE / AFP)MICHAEL TEWELDE/AFP/Getty Images AFP/Getty Images Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures Family members mourn the victims at the crash site of the Ethiopian Airlines operated Boeing 737 MAX aircraft, at Hama Quntushele village in the Oromia region, on March 13, 2019. - A Nairobi-bound Ethiopian Airlines Boeing crashed minutes after takeoff from Addis Ababa on March 10, 2019, killing all eight crew and 149 passengers on board, including tourists, business travellers, and "at least a dozen" UN staff. Families of the victims were taken to the remote site on March 13, 2019, where the plane smashed into a field with 157 passengers and crew from 35 countries, leaving a deep black crater and tiny scraps of debris. (Photo by TONY KARUMBA / AFP)TONY KARUMBA/AFP/Getty Images AFP/Getty Images Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures A page of a Boeing flight crew operations manual is seen at the scene of the Ethiopian Airlines Flight ET 302 plane crash, near the town of Bishoftu, near Addis Ababa, Ethiopia March 12, 2019. REUTERS/Baz Ratner REUTERS Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures epa07434278 Rescue workers search the site for pieces of the wreckage of an Ethiopia Airlines Boeing 737 Max 8 aircraft near Bishoftu, Ethiopia, 13 March 2019. Ethiopian Airlines flight ET 302 carrying 149 passengers and 8 crew was en route to Nairobi, Kenya, when it crashed on 10 March 2019 by yet undetermined reason. All passengers and crew aboard died in the crash. The Boeing 737 Max 8 aircraft has come under scrutiny after similar deadly crashes in Ethiopia and Indonesia within a few months. Several countries have banned the plane type from their airspace and many airlines have grounded their 737 Max 8 planes for safety concerns after the Ethiopian Airlines plane crashed minutes after take-off on 10 March. EPA/STRINGER EPA Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures A grounded Boeing 737 MAX 8 passenger plane of the Norwegian low-cost airline Norwegian is parked at the tarmac at Vantaa airport in Vantaa near Helsinki, Finland on March 13, 2019. - A number of countries have banned Boeing's 737 MAX 8 medium-haul workhorse jet from their airspace in response to the Ethiopian Airlines crash that killed all 157 people on board. (Photo by Heikki Saukkomaa / Lehtikuva / AFP) / Finland OUTHEIKKI SAUKKOMAA/AFP/Getty Images AFP/Getty Images Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures Rescue workers search the site for pieces of the wreckage of an Ethiopia Airlines Boeing 737 MAX 8 aircraft near Bishoftu, Ethiopia, 13 March 2019. Ethiopian Airlines flight ET 302 carrying 149 passengers and 8 crew was en route to Nairobi, Kenya, when it crashed on 10 March 2019 by yet undetermined reason. All passengers and crew aboard died in the crash. The Boeing 737 Max 8 aircraft has come under scrutiny after similar deadly crashes in Ethiopia and Indonesia within a few months. Several countries have banned the plane type from their airspace and many airlines have grounded their 737 Max 8 planes for safety concerns after the Ethiopian Airlines plane crashed minutes after take-off on 10 March. EPA/STRINGER EPA Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures A heap of debris from the wreckage of an Ethiopia Airlines Boeing 737 MAX 8 aircraft are piled at the crash site near Bishoftu, Ethiopia, 13 March 2019. Ethiopian Airlines flight ET 302 carrying 149 passengers and 8 crew was en route to Nairobi, Kenya, when it crashed on 10 March 2019 by yet undetermined reason. All passengers and crew aboard died in the crash. The Boeing 737 Max 8 aircraft has come under scrutiny after similar deadly crashes in Ethiopia and Indonesia within a few months. Several countries have banned the plane type from their airspace and many airlines have grounded their 737 Max 8 planes for safety concerns after the Ethiopian Airlines plane crashed minutes after take-off on 10 March. EPA/STR EPA Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures A crew working with an investigative team to clear the site after the Sunday crash of the Ethiopian Airlines operated Boeing 737 MAX aircraft, carry debris at Hama Quntushele village in the Oromia region, on March 13, 2019. - A Nairobi-bound Ethiopian Airlines Boeing crashed minutes after takeoff from Addis Ababa on March 10, killing all eight crew and 149 passengers on board, including tourists, business travellers, and "at least a dozen" UN staff. Families of the victims were taken to the remote site on March 13, 2019, where the plane smashed into a field with 157 passengers and crew from 35 countries, leaving a deep black crater and tiny scraps of debris. (Photo by TONY KARUMBA / AFP)TONY KARUMBA/AFP/Getty Images AFP/Getty Images Boeing 737 MAX grounding: Ethiopia Airlines Flight 302 in pictures FILE PHOTO: An American Airlines Boeing 737 MAX 8, on a flight from Miami to New York City, comes in for landing at LaGuardia Airport in New York, U.S., March 12, 2019. REUTERS/Shannon Stapleton/File Photo REUTERS

Reuters could not immediately verify the report. Boeing declined to comment.

“We are not commenting on an active accident investigation per international protocols,” a Boeing spokesman said.

The plane manufacturer said on Monday a proposed software enhancement package to MCAS would be submitted in the “coming weeks”, having previously said it would deliver the fix for US approval by last week.

A 737 pilot told Reuters last week it was “not physically easy to make large trim changes to correct, say, an MCAS input” by using the wheel.

“You – or more than likely the other pilot – have to flip out a little handle and wind, much like a boat winch,” the pilot said.

The Ethiopian Airlines pilots appeared to have restored power to the electric system to cope with a persistent steep nose-down angle, the paper said.

Their actions reactivated MCAS and allowed it to continue its strong downward commands that they were unable to counteract using electric thumb switches, the paper said.

The FAA directive after the Indonesian crash had instructed pilots to use cut-out switches in the centre console to shut off the electric power to the system.

The switches should remain off for the remainder of the flight, the FAA directive said.

A preliminary report by Ethiopian investigators is due within 30 days of the March 10 disaster, according to international rules governing crash investigations.

Ministry of Transport spokesman Musie Yehyies said there were no plans to publish the report on Wednesday.