The preliminary report into the Twin Otter crash at Mt Lawes in which four people died has revealed that a warning system did not sound off before impact.
This was revealed by the Air Crash Investigation Commission when it released the report today.
Both pilots of the aircraft and two passengers died in the crash on Sept 20th 2014 just before landing at Jackson Airport in Port Moresby.
The preliminary report was presented by AIC Chief Executive Officer David Inau, technical adviser Peter White, and AIC commissioners. Inau said from the outset that the preliminary report into aviation occurrences is factual and does not contain analysis, conclusions or recommendations.
The report was made following data downloaded from recording devices on board the aircraft.
It was presented to the media on the flight details of the Twin Otter, named Kilo Sierra Foxtrot, that left Woitape in Goilala on the morning of Sept 20th at 9:16am with two crew and seven passengers on a charter flight.
The weather in Woitape was fine however in Port Moresby it was poor, with low cloud cover and rain.
As it approached Port Moresby, Air Traffic Control cleared the flight crew to descend while maintaining visual separation from the terrain at the same time.
This was repeated as they descended.
When the aircraft was within 10 nautical miles of the airport, the pilot contacted the tower and mentioned the Instrument Landing System (ILS) but he did not request a discontinuation of the visual approach and he did not request radar vectors to position the aircraft for the Instrument Landing System.
Responding, the tower did not mention the ILS and repeated the clearance to make a visual approach. The clearance was read back by the pilot and soon afterwards, the air craft struck Mt Lawes.
The Twin Otter was fitted with an Enhanced Ground Proximity Warning System and preliminary indications from the cockpit voice recording are that aural warnings which are expected to go off from this equipment did not sound before the impact.
Inau said that a full and thorough investigation into the tragic incident will be conducted. This he said is expected to take months.