A Senate committee has recommended the Civil Aviation Safety Authority (CASA) relax maintenance requirements for aircraft involved in medical charity flights.

A Senate inquiry was launched earlier this year in response to a damning report by the Australian Transport Safety Bureau (ATSB) into Angel Flight - a charity flight provider.

The ATSB report came after the deaths of Emily and Tracy Redding, aged 16 and 43, who were killed along with 78-year-old pilot Grant Gilbert at Mount Gambier in South Australia's south-east.

Mr Gilbert was flying voluntarily for Angel Flight - a charity that coordinates non-emergency flights by recreational pilots so that residents of regional areas can reach medical appointments.

In August, the ATSB publicly released its two-year investigation into Angel Flight, finding the likelihood of a fatal crash was “was more than seven times higher than other private flights”.

The authorities said Angel Flight passengers are exposed to “much higher levels of risk”.

Angel Flight slammed the ATSB investigation, describing it as “demonstrably wrong”.

This led to a review by a Senate committee, which has now expressed “concerns” about findings in the ATSB report.

“The committee was disturbed to learn that the ATSB had not consulted with any Angel Flight pilots in reaching its conclusions about the pressure [on pilots] — perceived or otherwise,” it found.

“The ATSB has … provided no direct evidence to support its views that Angel Flight pilots are under more pressure to complete a flight than private pilots.

“The committee is concerned by the certitude of some of the conclusions drawn by the ATSB, from a dataset involving two incidents separated by six years, and over a 10-year period.”

The inquiry recommended CASA remove additional maintenance requirements for community service flights from the “community service flight (CSF) instrument” regulatory documents.

It said “maintenance concerns played no role in the 2011 and 2017 Angel Flight accidents”.

“In both instances, the ATSB concluded that there was no indication of unserviceable equipment or defects at the time of the accidents,” the Senate report found.

“The committee is of the view that the existing aircraft maintenance regime is adequate to ensure the safety of passengers and Angel Flight operators.

“The committee considers that the CSF instrument should be amended to remove those aeroplane maintenance requirements … which exceed the existing maintenance requirements for airworthiness in the general aviation sector.”

CASA has received the Senate review and says it will respond in detail at a later date.

“We are, however, somewhat perplexed that a Senate inquiry into the performance of the ATSB somehow results in two recommendations for a completely separate organisation, CASA,” a spokesperson said.

Centre Alliance senator Rex Patrick — who was part of the inquiry — described the ATSB's report as “lies, damned lies and statistics”.

“Angel Flight provides an invaluable service to regional communities who have families that require non-urgent, but critical medical services or families who need [disability] assistance for their loved ones,” he said.

“CASA has an over-regulation issue, so much so that the Government is progressing a bill through the Parliament that legally requires CASA to treat safety as primary, but to be mindful of the need to maintain a healthy industry.”