A source close to the pilot of a Mozambican aircraft that crashed in northern Namibia on November 29 killing all 33 people on board says it seems he deliberately crashed the plane as an act of suicide.

The source, who insisted on anonymity for fear of reprisals, said that Herminio dos Santos Fernandes had marital problems for about one and a half years.

Preliminary findings from an investigation into the plane crash released on Saturday indicated the pilot intentionally crashed the plane and had locked the co-pilot out of the cockpit.

According to the source, a colleague at Mozambican Airlines, Fernandes had been "very depressed" in the past two months due to his marital problems.

The workmate said the couple had not been speaking to each other.