Papua New Guinean officials were Friday trying to piece together how a passenger plane crashed in dense forest, killing 28 people -- but leaving four survivors -- in the nation's worst air disaster.
The survivors were the Australian and New Zealand pilots, a flight attendant, and a passenger believed to be a Chinese national, who reportedly escaped the fiery wreckage through a crack in the fuselage.
The Airlines PNG flight from the mountain gateway city of Lae to Madang, believed to be carrying parents travelling to see their children ahead of their university graduation, went down on Thursday as a heavy storm closed in.
"We had 32 people on board. Four survived and the rest sustained fatal injuries in the crash," the head of Papua New Guinea's Accident Investigation Commission David Inau told AFP via telephone.
"This will be the worst (crash) in terms of fatalities. This is the biggest, the highest fatality figures we've had."
Papua New Guinea authorities said the weather had been poor when the Bombardier Dash 8 aircraft came down in dense forest near the mouth of the Gogol River, about 20 kilometres (13 miles) from its destination.
But they were unable to confirm whether the storm caused the crash.
"There was some weather in the area and that's normal for Papua New Guinea in the afternoons, you do have thunderstorms and heavy rain," Inau said.
Reports said that villagers saw the plane crash and in flames, but Inau said it was not yet known whether the fire began while the aircraft was airborne or after impact.
One man reportedly told staff at a Madang hospital he escaped the burning wreckage through a break in the fuselage.
"He told the nurses he was sitting on the seventh seat and the plane broke in half," local journalist Scott Waide told the Australian Broadcasting Corporation.
"While struggling to get out, his arms got burnt and his back got burnt."
Nurses at the hospital confirmed to AFP that a middle-aged Asian man with burns to his back and arms, and other signs of trauma including bruising, had been brought in from the crash site. He was conscious and talking, they said.
The Australian pilot, believed to be in his 60s, has suffered leg injuries and was being taken to Port Moresby, Australian High Commission warden in Madang Trevor Hattersley said.
"The (Australian) pilot's leg is fairly bad, he can't walk, and the co-pilot is shaken up but I don't think he has any injuries," Hattersley told Australian news agency AAP.
More than 20 planes have crashed since 2000 in Papua New Guinea, whose jungle and mountainous terrain and lack of roads make air travel crucial for its six million citizens.
A 20-seat Twin Otter went down in August 2009, killing 13 people including nine Australians and a Japanese tourist.
That accident -- in which the aircraft ploughed into a mountainside -- also involved an Airlines PNG plane, with a subsequent report ruling pilot error was probably responsible.
PNG has since introduced legislation requiring all aircraft carrying more than nine people to have a cockpit recorder installed.
The impoverished South Pacific nation has only had an air accident commission since 2008, established in response to claims that corruption and a lack of funding had led to a sharp decline in safety standards.
Four Australian Transport Safety Bureau investigators were at the crash site to help with the investigation, while Airlines PNG grounded its Dash 8 fleet of 12 aircraft until further notice.
Most of the passengers were believed to be Papua New Guineans heading to Madang for thanksgiving ceremonies ahead of the graduation of fourth-year students at Divine Word University.