The ATSB Interim Factual Investigation Report into the Metroliner fatal aircraft accident on 7 May 2005 near Lockhart River has found that if the ground proximity warning system functioned as designed, the crew should have received a number of warnings from the system as the aircraft descended below the minimum obstacle clearance altitude of 2,060 ft.
However, because no data on the cockpit voice recorder (CVR) was useable, the functionality of the warnings could not be confirmed. Flight data recorder information from the accident aircraft continues to assist with the ATSB investigation.
Aircraft VH-TFU was 11 km north-west of Lockhart River aerodrome on the final instrument approach track for runway 12, travelling at about 290 km/hr, when it collided with South Pap, a steep tree covered ridge in the Iron Range National Park.
The two pilots and 13 fare-paying passengers perished, and the aircraft was totally destroyed by massive overload forces as the aircraft collided with trees and large boulders during the impact sequence, and the intense fuel-fed fire which followed.
Although the weather conditions in the Lockhart River area on the day of the accident were worse than originally forecast, the crew was advised by Brisbane air traffic control of the amended forecast details more than two hours prior to commencing the approach to Lockhart River. The weather conditions at the time of the accident were reported as being broken low cloud with squally rain showers and drizzle.
Air traffic control tapes indicate that the copilot was making radio calls during the flight, which may indicate that the pilot-in-command was flying the aircraft, but this has not been able to be confirmed.
The investigation is continuing and because of the extent of the damage to the aircraft and loss of CVR data, is extremely complex and painstaking.
The full report is available on the ATSB website.