ATSB releases preliminary report on Queensland crash

The Australian Transport Safety Bureau (ATSB) has released a preliminary report on the crash of a firefighting plane in Queensland last year.

The report details evidence relating to the crash of a Gulfstream 695A twin-turboprop fixed-wing aircraft on 4 November 2023, which resulted in three fatalities.

The aircraft, owned by AGAIR, was serving under a contract with Queensland Fire and Emergency Services. At the time of the incident, it was in transit to conduct fire surveillance in the Australian state’s northwestern regions.

Operations prior to the crash

According to the preliminary report, the aircraft had taken off from Toowoomba to photograph fire zones near Mount Isa.

After flying for approximately 20 minutes, it reached the planned cruise altitude of 28,000ft (8,534.4m). It then descended to 15,000ft, maintaining that height for approximately six minutes, before returning to 28,000ft.

After another 25 minutes, the air traffic controller sent a request to the pilot for the plane to change its radio frequency – a request that the pilot acknowledged.

Despite this, the controller was subsequently unable to establish two-way communications with the plane for over an hour afterwards.

A “substantially lowered” rate of speech from the pilot

When communications were re-established, the pilot told the controller that they were going to conduct air work near Mount Gordon. When provided clearance for this, the pilot then subsequently repeated the clearance four times over the next four minutes, suggesting that they were uncertain.

According to ATSB Chief Commissioner Angus Mitchell: “Although a formal speech analysis has not been undertaken at this stage, radio recordings during this period indicate that the pilot’s rate and volume of speech had substantially lowered from earlier communications and was worsening.”

Around 20 minutes after the pilot’s last transmission, flight data suggests that the aircraft’s groundspeed decreased, and that it began descending rapidly. The aircraft then impacted terrain in an area of open, flat bushland, and was destroyed in the resulting fire.

Engines were running on impact

The report noted that during onsite examinations, all major aircraft components were accounted for, while both propellers and engines had indications suggesting that they were in operation during the impact. It was not, however, possible to determine the operability of the aircraft’s oxygen and pressurization systems.

The ATSB has also been working to interview relevant parties, and to collect radio communications recordings, flight data, and all relevant documentation alongside its onsite work.

Mitchell confirmed: “As the investigation proceeds, it will include further analysis of the pilot’s speech during radio communications, including an examination of hypoxia indicators. Investigators will also analyze weather information, maintenance records, operational procedures, flight data, and pilot and crew training and medical records.”

“If at any time should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so safety action can be taken,” Mitchell concluded.

A preliminary report on the crash of an Air Evac Lifeteam helicopter in the US state of Oklahoma was released by the US National Transportation Safety Board (NTSB) earlier this month.