An Ethiopian Airlines Boeing 737 Max nosedived several times before it came down in a fatal crash last month, a preliminary report has found.
There were no survivors following the incident shortly after take-off.
Pilots “repeatedly” followed procedures recommended by Boeing before the crash, according to the first official report into the disaster.
Flight ET302 crashed after take-off from Addis Ababa, killing 157 people.
It was the second crash of a Boeing 737 Max aircraft in five months.
Last October, Lion Air flight JT 610 crashed into the sea near Indonesia killing all 189 people on board.
Despite their efforts, pilots on board the Ethiopian Airlines plane “were not able to control the aircraft,” Ethiopian transport minister Dagmawit Moges said.
“The crew performed all the procedures repeatedly provided by the manufacturer but were not able to control the aircraft,” Moges said in a news conference.
Boeing said earlier this week it would need more time to finalise a software fix for the Boeing 737 Max.
The manufacturer is working on an update to the manoeuvring characteristics augmentation system, which has been implicated in the crashes.
The global fleet of the aircraft type, roughly 400 planes, is currently grounded following a decision by the FAA.
Responding to the report Ethiopian Airlines chief executive, Tewolde GebreMariam, praised the pilots.
“We are very proud of our pilots’ compliances to follow the emergency procedures and high level of professional performances in such extremely difficult situations,” he said.
“We are also very proud of our Global standard Pilot Training Centre and the Ethiopian Aviation Academy which is one of the largest and most modern in the world equipped with state of the art and latest training technologies.”