Flight data from the Ethiopian Airlines disaster a week ago suggest "clear similarities" with a crash off Indonesia last October, Ethiopia's transport minister has said.
Both planes were Boeing 737 Max 8 aircraft.
Last Sunday the Ethiopian Airlines jet crashed after take-off from Addis Ababa, killing all 157 people on board.
Transport Minister Dagmawit Moges told journalists that a preliminary report would be released within 30 days.
"Clear similarities were noted between Ethiopian Airlines Flight 302 and Indonesian Lion Air Flight 610, which would be the subject of further study during the investigation," Ms Dagmawit told journalists on Sunday.
In both cases flight tracking data showed the aircraft's altitude had fluctuated sharply, as the planes seemed to experience erratic climbs and descents.
Boeing Chairman and CEO Dennis Muilenburg later reaffirmed that the company was supporting the investigation.
In a statement, he added that Boeing was going ahead with a software update that will address the behaviour of the flight control system "in response to erroneous sensor inputs".
Also on Sunday, ceremonies took place both in Kenya and Ethiopia to honour the victims.
Thousands of people gathered in the Holy Trinity cathedral in Addis Ababa where empty coffins were draped in the national flag. None of the bodies has yet been formally identified because of the impact.