The process will be complicated because the passengers came from more than 30 countries and Ethiopia has limited forensic capabilities, the expert added, asking not to be named.
But he says more questions need to be answered.
CEO Tewolde GebreMariam told CNN's Richard Quest on Tuesday that a recorded conversation with air traffic control detailed the final moments of the flight. "However, this investigation has just begun and to date we have not been provided data to draw any conclusions or take any actions".
It was the second crash involving the 737 Max 8 model in less than five months, after the Lion Air crash off Indonesia in which 189 people died in October. Major U.S. airlines such as Southwest- which uses 34 Boeing 737 Max 8 aircraft - say they're confident in the plane.
In response, the world's biggest planemaker, which has seen billions of dollars wiped off its market value, said it understood the decisions but retained "full confidence" in the 737 MAX and had safety as its priority.
US officials said the devices suffered some damage but they were confident of some initial results within 24 hours of the data being downloaded.
In a statement released Monday, the World Food Programme, which accounted for the largest number of deaths, said it is in mourning for seven WFP staff members who lost their lives.
There is no evidence the two crashes are linked. And Nikki Haley, Trump's former United Nations ambassador, has been nominated to join Boeing's board.
But October's Lion Air crash in Indonesia sparked a debate on automation, particularly over a software system created to push the plane down to stop a stall during flight.
Little is known about the Ethiopian Airlines pilots flying the jet on Sunday morning.
At the rural site where Flight ET 302, which was bound for the Kenyan capital Nairobi, came down near the village of Gora-Bokka, dozens of grief-stricken relatives paid their respects.
The problem presents "a potential for repeated nose-down trim commands", the directive states, noting, "This condition, if not addressed, could cause the flight crew to have difficulty controlling the airplane" and possibly resulting in a crash.
Canada has no plans to ground 737 MAX aircraft but is ready to act to suspend flights if new information emerges indicating there is a problem, Transport Minister Marc Garneau said.
With Ethiopia reeling from its worst plane crash in its history, the likes of Fekadu and Getu are hoping such tragedies will no longer happen in the future, and hope the Ethiopian government undertakes an exhaustive investigation into the incident.