The black box from the Ethiopian Airlines crash that killed 157 people will be sent abroad for analysis, the airline said on Wednesday.
Ethiopian Airlines' CEO Tewolde Gebremariam told CNN that the pilots had informed air traffic control that they were having flight problems before the crash.
Two black boxes were recovered from the crash site on Monday, one holding voice recordings and other digital data.
Mr Tewolde said he did not know if the boxes would be sent to the United States, but said, "it could also be a closer country in Europe in the interest of proximity and in the interest of speed."
Two American agencies, the Federal Aviation Authority and National Transportation Safety Board are assisting the Ethiopian Authorities in the investigation, along with the plane manufacturer Boeing.
As the "state of occurrence," Ethiopian authorities will lead the investigation, Graham Braithwaite, a professor of safety and accident investigation at Cranfield University in the United Kingdom, told The National.
"If there are particular skills that may come from another state or indeed any other agency, for example a university, then it is appropriate that the investigator in charge [Ethiopia] can invite them to participate," Mr Braithwaite said. He added that it is not unusual for the flight black boxes to be sent overseas as not every country has the equipment needed to analyse the data.
"Aircraft accident investigation depends on international collaboration — all with the common goal of improving flight safety," he said.
Data from the black box will hold crucial information on whether the Ethiopian Airlines flight experienced the same issues as a crashed Lion Air flight of the same model five months ago.
Concerns over the safety of the Boeing 737 Max has prompted airlines and aviation authorities to ground the aircraft or stop it flying in their airspace.
Mr Tewolde said while speculation about the safety of the aircraft is not helpful, there are "questions without answers on the aircraft."
The airline CEO said there are "very significant similarities" between the Ethiopian Airlines crash and that of Lion Air.
