Community service flights conducted by a charity group have a fatal accident rate seven times higher than other private flights, an investigation has found.

The Australian Transport Safety Bureau says its probe of the Angel Flight service after two fatal crashes in the past decade found its pilots and passengers are being exposed to much higher risks.

“Angel Flight did not pressure pilots to fly in conditions beyond their capability, but some circumstances can lead a pilot to feel pressure anyway, such as the responsibility to fly unrelated ill passengers to meet medical deadlines,” ATSB chief commissioner Greg Hood said on Tuesday.

“This can lead to degraded decision making under high-pressure situations, like when confronted with poor weather.”

The ATSB investigation came after a pilot and two passengers were killed when an Angel Flight service crashed at Mt Gambier in July 2017.

Businessman Grant Gilbert, 78, was flying the SOCATA TB-10 Tobago and was taking 16-year-old Emily Redding from Mt Gambier to Adelaide for medical treatment.

Also on board was the teenager’s mother, 43-year-old Tracy Redding.

The investigation found Mr Gilbert took off in low-level cloud without proficiency for instrument flying conditions.

Shortly after take-off, he likely lost visual cues and probably became spatially disorientated, resulting in loss of control, the ATSB said.

On the same day, two regional airline flights into Mt Gambier had been delayed because of poor weather.

Commissioner Hood said the community could reasonably expect that community service flights would have a level of safety similar to other private operations, if not higher.

“However, this investigation has shown that those conducted for Angel Flight are actually less safe than other private operations, let alone charter and scheduled airline flying,” he said.

The ATSB said Angel Flight was to be commended for taking action on a number of safety issues including the development of an online safety course and implementing a safety management system.

But it recommended Angel Flight consider paying for commercial flights where they are available to transport its passengers.

It said commercial flight options are available for nearly two-thirds of the private flights organised by the charity and suitable options were available in Mt Gambier on the day of the crash.

Angel Flight could purchase tickets on commercial flights for two passengers for a comparable cost to the organisation to what they normally reimburse for the fuel costs of privately-operated flights, the ATSB said.

-AAP