An "unknown mechanical failure" caused the fiery Queensland Raceway crash that killed British motor racer Sean Edwards, a coroner has found.
Deputy State Coroner John Lock on Friday handed down his findings into the horrific 2013 accident that killed Edwards, the son of Formula One driver Guy Edwards, and severely injured experienced amateur Will Holzheimer.
He found the brakes of their Porsche 996 GT3 "totally failed" as a result of the mechanical glitch, causing the car to slam into a tyre barrier and concrete wall at 145km/h and catch fire.
Mr Lock was unable to pinpoint what caused the malfunction but suggested some type of mechanism causing the throttle to lock on or the ABS being "tripped" as possibilities.
Edwards, a Monaco-based professional driver, was hired by Mr Holzheimer's father for two days of coaching.
The young driver survived the crash but suffered injuries so severe he had to learn how to walk again.
The coroner found he had not been driving recklessly before the crash, nor had his instructor done anything to risk their safety as they looped the track.
Mr Lock said anything either man did after the mechanical failure would've been "futile" to stop impact.
He noted the inherently risky nature of motorsport, and conceded participants were tasked with accepting this, but said designs around gravel traps and barriers could help prevent future deaths.
"Or, at the least, informing participants of that risk so they can take appropriate steps to improve safety and reduce the risk of death and serious injury," he found.