Inquest fails to solve mystery of 'ghost plane' that flew for six hours

One of Australia's most mysterious air accidents is destined to remain unexplained for ever. An inquest into the deaths of eight men whose plane flew unpiloted across the Outback for six hours before crashing on a remote cattle station proved inconclusive.

One of Australia's most mysterious air accidents is destined to remain unexplained for ever. An inquest into the deaths of eight men whose plane flew unpiloted across the Outback for six hours before crashing on a remote cattle station proved inconclusive.

The twin-propeller Beechcraft Super King Air 200 apparently lost cabin pressure soon after take-off from Perth, and the pilot and seven passengers were all dead or unconscious as it flew nearly 2,000 miles on a silent "ghost flight" across the continent. Air traffic controllers frantically trying to make contact could hear only the pilot's laboured breathing and were forced to watch helplessly as the doomed plane flew through the night and into oblivion.

It finally ran out of fuel and plunged to the ground near Mount Isa, in western Queensland, bursting into flames.

Alistair Hope, the Western Australia coroner, said yesterday that the men – all bound for a gold-mining town north-east of Perth – were clearly dead or incapacitated for most of the flight. But determining whether they lost consciousness because of oxygen deprivation or inhaling toxic fumes was an impossible task.

Mr Hope severely criticised the Australian Transport Safety Bureau, which he said had failed to co-operate with other agencies and did not order full toxicology reports on the victims until a year after the crash in September 2000.

The men, all employees of one of Australia's biggest gold producers, Sons of Gwalia, were returning to a mine at Leonora after a two-week break in Perth. In the final stages of the chartered plane's eerie journey, it was shadowed by several other aircraft that tried in vain to make contact and watched powerlessly as it fell to the ground.

Anthony Ayliffe, a Melbourne air traffic controller, wept as a recording of his last conversation with the pilot, Ken Mosedale, was played at the inquest. Mr Ayliffe tried to contact Mr Mosedale half an hour after take-off, when the plane – which had departed safely from Perth – was at 25,600ft, 600ft above its authorised altitude.

Asked to verify his position, the pilot replied: "Sierra, Kilo, Charlie ... um ... stand-by." For the next nine minutes, the tape recorded only silence punctuated by breathing and background noises as Mr Mosedale's microphone switched itself on and off before going dead. Mr Ayliffe told the court of his sense of hopelessness when he failed to get a reply.

The bureau believes the plane became depressurised soon after take-off and flew on auto-pilot until it ran out of fuel.