An official with the Ministry of Civil Aviation in Papua New Guinea says mechanical fault appears to be the most likely cause of last Thursday's plane crash which killed 28 people.
Investigators from Australia's Air Transport Safety Bureau are assisting the PNG Accident Investigation Commission to establish why the Airlines PNG Dash-8 aircraft crashed about 30 kilometres south of Madang town.
The plane's black box voice recorder has been recovered and sent to Australia for analysis.
But the first secretary to the Minister for Civil Aviation, Levai Wama, says it already looks like there was a mechanical fault on the plane.
"Based on the information that the pilot gave to the towers which was there's smoke coming out of the engines and we're running out of power, doing a forced landing, that's what they said, which resulted in it crash landing."
Levai Wama says a team from Canada representing the airframe manufacturers and engine makers are doing their own investigations.
Meanwhile, the chairman of Airlines PNG has defended the company's commitment to safety following the crash.
In a statement on the company website, Simon Wild expresses his sorrow at the tragedy.
The government has cancelled the planned merger of Airlines PNG with the state-owned carrier Air Niugini as a result of the crash.
In 2009 13 people were killed after an Airlines PNG flight went down just north of the village of Isurava and questions are being asked about the company's safety record.
But the chairman says safety is the first priority of the business and says in the past year alone that the airline has passed 16 safety audits.