A Gold Coast pilot was performing manoeuvres below 500-feet in a Soviet-era aircraft before crashing into the ocean at high speed, killing both himself and his passenger in 2019, an inquest has found.
Investigators were not able to determine with certainty that pilot Martinus van Hattem was completing an aerobatic manoeuvre immediately before the crash, but it was considered a possibility.
The 52-year-old pilot and his passenger, Trista Applebee, 31, were killed when his Yak-52 vintage military aircraft crashed into the ocean off South Stradbroke Island.
The flight in the two-seater, single engine aeroplane had been a birthday present to Ms Applebee from a friend, who had paid Mr van Hattem $200 for two 30-minute flights.
Parts of the wreckage were found on the same day as the crash, and the bodies of Mr van Hattem and Ms Applebee were found in the following days.
A coroner's report noted that Mr van Hattem had been given two prior formal or written warnings about performing acrobatics and low flying in the years before the crash.
The first warning came in 2013, after Mr van Hattem admitted he let someone parachute from his kit-built aircraft. He said that he did not know he needed approval to do so.
Mr Van Hattem received the second warning for performing low-level acrobatic manoeuvres over a residential area near Southport Airport in the Yak-52 aircraft during 2018.
The inquest also looked at footage from another 2019 flight, which Australian Transport Safety Bureau (ATSB) investigators said showed Mr van Hattem performing aerobatics below 1,000 feet.
The ATSB said some parts of the flight were as low as 260 feet.
Mr van Hattem had not completed enough training to be endorsed to conduct aerobatics below 3,000 feet, according to the inquest findings.
Coroner Carol Lee said the spread of the wreckage from the 2019 crash was so great that it hindered the coronial inquest.
"One of the significant impediments with this investigation was the limited wreckage able to be recovered," Mr Lee said on Tuesday.
She said that meant that no examination was able to be undertaken to precisely determine what exactly might have caused the crash.
The inquest findings highlighted issues about aerobatic flying and the training and the regulative system in relation to the Yak-52 aircraft.
Ms Lee made 13 recommendations aimed at avoiding similar crashes in the future.
