Lack of oxygen could have caused fatal plane crash that killed three people: ATSB

A lack of oxygen in the blood supply may have caused a plane crash that killed three members of an aerial firefighting crew in November, an Australian Transport Safety Bureau (ATSB) report suggests.

The plane took off from Toowoomba on November 4 and was on its way to photograph fire zones north of Mount Isa.

On board were a pilot and two camera operators, including 22-year-old William Jennings from the US, all of whom died in the crash.

The report states that there were issues with communications between the air traffic controller and the pilot during the flight.

At one stage, the pilot informed the air traffic controller that oxygen systems were working in the aircraft, the ATSB report stated.

Later on, the pilot advised the controller they were to conduct airwork — aerial surveying — in an area near Mount Gordon.

When they were provided clearance for this, the pilot, seeming uncertain, repeated the clearance four times over a four-minute period.

During the last radio transmission, the pilot seemingly had difficulty pronouncing certain words, the ATSB report stated.

“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,” ATSB Chief Commissioner Angus Mitchell said.

Flight data indicates approximately 20 minutes after the pilot’s last transmission, the aircraft began to descend rapidly.

The plane crashed in flat, open bushland near Cloncurry, in north-west Queensland and was destroyed by a significant post-impact fire.

Investigation ongoing

The ATSB report stated that all parts of the aircraft were recovered and that both engines and propellers had indications they were running at impact.

However, it was not possible to determine the operability of the aircraft’s pressurisation and oxygen systems, the ATSB said.

“As the investigation proceeds, it will include further analysis of the pilot’s speech during radio communications, including an examination of hypoxia indicators,” Mr Mitchell said.

“Investigators will also analyse weather information, maintenance records, operational procedures, flight data, and pilot and crew training and medical records.”

Hypoxia is a state where a physiologically inadequate amount of oxygen is available to or utilised by tissue.

A final report will be released at the conclusion of the investigation.