Whistleblowers told the paper that understaffing was resulting in overworked and tired pilots who are more likely to slip up.

“They’re all great people but the demands on their roster are so great. Small mistakes are creeping in. The workforce is concerned a small mistake could become a big mistake,” one paramedic said.

In a statement, Pel-Air said that its investigations of all three incidents indicated it was “unlikely” that pilot fatigue was a factor in any of them.

“Each pilot, before starting a rostered duty, is assessed on his/her individual fatigue score according to the biomedical model which takes into consideration the cumulative effect of duties in the prior fortnight. No pilot can be put on duty if their fatigue score is below the minimum safe level according to the predictive model,” the statement read.

“In addition, every pilot who feels fatigued (in spite of having a fatigue score above the safe level) must report this to the supervisor who will mobilise the reserve pilot if the fatigue is serious. In all three incidents, the pilots had a score of over 90 with the minimum threshold at 77.”

The company added that it is “not immune to the legacy effects of COVID”, which has caused a “world and industry-wide shortage of fixed-wing pilots, especially for the smaller aircraft”.

“Be that as it may, any causal link between the pilot numbers and pilot fatigue is simply not possible given that Pel-Air has in place a fatigue monitoring system explained above that sits above the Civil Aviation Safety Authority’s (CASA) very prescriptive rules on pilot duty hours,” said Pel-Air.

“We understand the concerns of the informant but, having completed over 12 years of flying for AV with impeccable reliability and an unblemished safety record, we believe that Pel-Air has earned the right to be trusted and relied upon.”

Ambulance Victoria has stood by Pel-Air, which last month commenced a new $300 million 12-year contract signed in 2022 to continue to supply aeromedical services using four Beechcraft King Air aircraft plus pilots and engineers.

Anthony Carlyon, executive director of clinical operations at Ambulance Victoria, told the Herald Sun that the planes are free of mechanical defects and still in service.

“Ambulance Victoria takes the safety of our people and patients very seriously,” he said.

“Any in-flight incidents are reported promptly, in line with protocols to ensure our high standards for safety and service are delivered – and our contracted aeromedical partner Pel-Air conducts maintenance and safety checks on the aircraft after each event.”