It said air speed and altitude values on the left side of the 737 Max conflicted with data from the right sensor, causing flight control problems.
The head of Ethiopian Airlines Tewolde, GebreMariam, said he was proud of the efforts of the pilots in trying to stop their jet from crashing.
When the pilots restored power to the horizontal stabilizer however, the MCAS re-engaged and forced the nose of the plane down again and the pilots were unable to pull the plane out of the nosedive that followed.
People close to the Ethiopian investigation have said the anti-stall software - which automatically pushes the aircraft's nose down to guard against a loss of lift - was activated by erroneous "angle of attack" data from a single sensor.
Dagmawit did not make specific reference to the automatic anti-stalling system, but did mention a "repetitive nose-down" movement of the aircraft.More news: Android Q Beta 2 arrives with zoomable microphones, Bubbles, and more
News of the report's impending release came as the Federal Aviation Administration announced a new review of the 737 MAX and as the head of Boeing joined a test flight created to demonstrate the effectiveness of the company's proposed fix.
Boeing has issued guidance to pilots on how to manage MCAS, and it plans to install an extra warning system on all 737 Max aircraft, which was previously an optional safety feature.
It recommended that Boeing review its flight-control systems and that regulators properly verify the review.
She said the report recommended that Boeing should review the aircraft flight control system.
Ethiopian Minister Dagmawit Moges said that the Boeing 737 MAX aircraft was in good condition before take-off. "Flight crews will always have the ability to override MCAS and manually control the airplane", the company said.More news: Joe Biden jokes about inappropriate touching during a speech
But in a clear indication of where Ethiopian investigators are directing the attention of regulators, they cleared the pilots of using incorrect procedures and issued two safety recommendations focused on the recently introduced aircraft. Nor did it give a detailed analysis of the flight, which is expected to take several months before a final report due within a year.
Ethiopia's Transport Minister Dagmawit Moges' comments were based on a preliminary report, which has not yet been published. "It is so sad to learn that our loved ones would have been spared if this problem was detected on time". "I've never seen so little information in a report".
Ethiopian Airlines Boeing 737-800 parked at Bole International Airport in Addis Ababa, Ethiopia. The complaint, which also names Ethiopian Airlines and parts maker Rosemount Aerospace as defendants, alleged negligence and civil conspiracy among other charges.
The Kenyan group follows a Rwandan family who filed suit against Boeing in late March.
Stumo, originally from MA, is the niece of consumer activist Ralph Nader, who called for a boycott of the 737 MAX on Thursday. The FAA launched a review of the 737 Max.
This is the second time a Boeing crash has ended in fatality in the past five months.More news: Watch NCAA Tournament Game Online
- The chairman of the U.S. House of Representatives transportation committee and another key Democrat asked the Transportation Department's inspector general to examine key decisions the FAA made in certifying the MAX jet.