Investigators have determined that evacuation of the Air Niugini Boeing 737-800 which undershot into the sea at Chuuk was slowed by occupants trying to retrieve baggage.
The aircraft was lightly loaded, with just 35 passengers and 12 crew members on board, when it came down short of the runway on 28 September last year.
Papua New Guinea's Accident Investigation Commission says that it "noted with concern" that there were "many instances of non-compliance" with evacuation directives prohibiting baggage from being taken from the aircraft during evacuation.
"A couple of passengers stated in their response to [the commission's] written questionnaire that they were annoyed that a cabin crew member at the overwing exit forced them to leave cabin baggage in the aircraft," it says.
Despite these instructions, the inquiry adds, several passengers still emerged from the wrecked aircraft with their bags.
Images reviewed by the commission found evidence that a loadmaster on board had his hands full with a backpack, clipboard and shoes when he left.
The commission has detailed two particular instances where passengers' baggage removal "slowed" the evacuation.
One passenger stopped inside the aircraft and leaned out a right-hand overwing exit to pass a carry-on bag to a US Navy diver standing on the wing. The diver first threw the bag into an inflatable boat before assisting the passenger from the aircraft.
He removed his life-jacket and happened to be wearing a shirt beneath on which was printed 'US Navy', which "gave the appearance" that he was part of the actual US Navy rescue team, and he remained on the wing trying to assist divers to evacuate occupants.
The second occurrence involved a passenger who, having initially exited with cabin baggage, was then assisted by divers with re-entering the aircraft to retrieve shoes.
Cabin crew members pointed out to the investigators that some passengers appeared not to understand the word 'evacuate', but understood and followed the instruction to 'get out'.
No passengers had been seated in the overwing exit rows, so none was briefed on opening these exits. A flight attendant responsible for the exits moved forward from her station at the rear of the cabin, but had to barge through with "mild force" and "shove passengers out of her way" owing to congestion in the aisle, says the inquiry.
"This flight did not have a full passenger load. There were numerous empty seats," it adds. "In the event of a full-capacity flight, the cabin crew would have had significant difficulty reaching the overwing emergency exit."