Ethiopia's probe of last year's Ethiopian Airlines crash found that Boeing did not provide sufficient training for the 737 MAX and crucial flight software was flawed, according to an interim report published on Monday.

The crash of the Nairobi-bound Boeing 737 MAX six minutes after takeoff on March 10, 2019, killed all 157 people on board, triggering the global grounding of the MAX in the worst crisis in Boeing's history.

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It followed the October 2018 crash of a 737 MAX operated by Lion Air in Indonesia, which killed 189 people when it went down moments after leaving Jakarta airport.

Both accidents saw uncontrolled drops in the aircraft's nose in the moments before the planes crashed, which investigators have blamed on the model's anti-stall flight system, the Maneuvering Characteristics Augmentation System, or MCAS.

A preliminary report by Ethiopian investigators released last April said the crew of Flight 302 repeatedly followed procedures recommended by Boeing, but were unable to regain control of the jet.

Final moments

The report included details of the final exchanges between Captain Yared Getachew and First Officer Ahmednur Mohammed, including Yared imploring Ahmednur to "keep with me" as Ahmednur struggled to get control of the aircraft.

At one point, Yared urged Ahmedur to "pull with me" as both men applied force to the control column.

The final readings of the flight indicate it was moving as fast as 500 knots (more than 900 kilometres per hour) and descending at a rate of greater than 10,000 metres per minute (33,000 feet per minute), the report said.

The plane crashed in a field southeast of the capital Addis Ababa, leaving a crater 10 metres deep "with a hole of about 28 metres width and 40 metres length", the report said.

Plane fragments were found hundreds of metres away, it said.

Boeing could not immediately be reached for comment Monday.

'Inadequate training'

The new report said the design of the MCAS system "made it vulnerable to undesirable activation", adding

Specifically, it pointed to the fact the system could be activated by a single angle-of-attack sensor reading.

The indicators measure the plane's angle vis-a-vis oncoming air to warn of impending stalls.

The report also said the training provided by Boeing on the 737 MAX "was found to be inadequate".

It recommended training simulators need to be capable of simulating scenarios in which the sensor fails.

The new interim report was released a day before the one-year anniversary of the Ethiopian Airlines crash.

Relatives of many of the victims, who hailed from more than 30 countries, have flown to Ethiopia and are expected to attend a memorial ceremony at the crash site on Tuesday.

Last week, a US congressional committee said Boeing made missteps and withheld information about the 737 MAX, and that federal regulators failed to provide proper oversight resulting in a "fundamentally flawed" aircraft.