2000 Australia Beechcraft King Air Crash - Accident

Accident

On 4 September 2000, the aircraft, chartered by mining company Sons of Gwalia, departed Perth, Western Australia, for the mining town of Leonora, Western Australia, transporting seven workers to Gwalia Gold Mine. The aircraft took off from Perth at 6:09 pm local time (1009 Coordinated Universal Time (UTC)), and one minute later was cleared by ATC to climb to FL130 (13,000 feet (4,000 m)). Five minutes later, at 1015, the aircraft was cleared to ascend to its cruising altitude of FL250 (25,000 feet (7,600 m)); the pilot was told to ascend to FL160 by the time it was 36 nmi (67 km) from Perth. The pilot acknowledged this transmission.

Five minutes later, at 1020, as the aircraft passed through FL156 (15,600 feet (4,800 m)) it was cleared to waypoint DEBRA; the pilot acknowledged this. At approximately 1033 the aircraft ascended through FL256 (25,600 feet (7,800 m)) and ATC requested the pilot to confirm the altitude of the aircraft. “Sierra Kilo Charlie–um–standby," the pilot said. This was the final spoken transmission from the aircraft, and the altitude of the aircraft continued to increase. According to the accident report, transmissions from the aircraft thereafter were only open-microphone transmissions, sounds of what is believed to be standard background noise produced by the engines, a person breathing, "one unintelligible syllable" and "two chime-like tones, similar to those generated by electronic devices." ATC attempted to regain contact with the aircraft as the transmissions occurred. "Sierra Kilo Charlie Sierra Kilo Charlie Melbourne Centre if receiving this transmission squawk ident" the controller in contact with the aircraft said at 1040. At 1041, the controller asked again, "Sierra Kilo Charlie only receiving open mike from you. Would you contact me on one two five decimal two."

The aircraft continued to ascend and left radar coverage at 1102, climbing through FL325 (32,500 feet (9,900 m)). Thirty-one minutes later, Australian Search and Rescue contacted a business jet to request the aircraft fly near the Beechcraft to observe the situation aboard. The flight crew of the jet said the Beechcraft had levelled off at FL343 (34,300 feet (10,500 m)), and there was no movement on the flight deck or in the cabin. They added the conditions made it difficult to make observations of the situation of the Beechcraft.

Two other aircraft were then told to intercept and monitor the Beechcraft; they sighted it in the Northern Territory, northwest of Alice Springs. The flight crews of the aircraft reported the Beechcraft was making a steady descent. Both aircraft followed the Beechcraft during the descent. The airspeed of the Beechcraft increased during the descent. "Although its external lights were on, nothing could be seen inside the cabin" the accident report stated. "The crews of the chase aircraft attempted to contact the pilot of the Beechcraft by radio but they did not receive a response." At 1510, the aircraft turned left through 90 degrees as it descended through 5,000 feet (1,500 m). The aircraft impacted with the ground near Mount Isa, Queensland. Upon impact the aircraft broke up; all seven passengers and the pilot died.