US air crash investigators have challenged the conclusions of an Ethiopian inquiry into the Boeing 737 Max crash in Addis Ababa nearly four years ago.
The experts argue that the Ethiopian inquiry focusses on technical issues and not sufficient attention is paid to the actions of the crew.
The accident was the second involving a Boeing 737 Max in the space of five months.
The crash led to the worldwide grounding of all aircraft of this type.
The accident was initially attributed to the technical failure of a sensor that triggered a number of automated procedures that ultimately led to the accident.
While not rejecting the conclusions of the Ethiopian inquiry, US investigators claim that more analysis is required to examine human factors and inadequate pilot response.