The final report on the Beech Super King Air 200 VH-SKC accident, in which all eight occupants died when a charter flight from Perth on 4 September 2000 overflew Leonora and then the NT before crashing near Burketown QLD, was released today by the Australian Transport Safety Bureau.
ATSB Executive Director, Kym Bills, made the following statement:
"Based on the available evidence, including voice analysis of air traffic control tapes, the investigation concluded that the pilot and passengers were probably incapacitated as a result of hypobaric (altitude) hypoxia due to the aircraft being unpressurised and their not receiving supplemental oxygen.
The extent of damage to the King Air after it impacted the ground at about 240 kts (445 km/h) and the constraints associated with the subsequent autopsies as a result of the hot, remote crash site, made this investigation particularly difficult.
However, testing established that carbon monoxide and hydrogen cyanide were unlikely to have been factors.
The reason for the aircraft probably being unpressurised (such as lack of hull integrity and/or bleed air not operating) or why the pilot and passengers did not receive supplemental oxygen to prevent hypobaric hypoxia, could not be determined from the evidence.
The investigation concluded that setting the aircraft's visual alert to operate when the cabin altitude pressure exceeded 10,000 feet rather than 12,500 feet and adding an aural warning to operate in conjunction with the visual alert, may have prevented the accident.
In December 2000 the ATSB made recommendations to CASA along these lines based on an earlier occurrence, which the regulator has accepted."