Drugs, stress 'likely impaired' Sea World tragedy pilot

A helicopter pilot involved in a fatal mid-air collision was probably affected by cocaine withdrawal, an alcohol hangover and fatigue at the time, a coroner has heard.

A toxicologist who gave evidence at mushroom murderer Erin Patterson's trial was among a panel of experts speaking about the likely effects at an inquest into the tragedy on Wednesday.

Ashley Jenkinson, 40, was among four people killed when his Sea World chopper collided mid-air with another outside the Gold Coast theme park on January 2, 2023.

Mr Jenkinson tested positive to cocaine during an autopsy, coroner Carol Lee has heard, but a Australian Transport Safety Bureau investigation found he was "unlikely to have been directly affected by the drug at the time of the accident".

The pilot was seen inhaling multiple lines of cocaine, and drinking 12 beers and whiskey at a New Year's Eve party before the crash.

He had a lower level of cocaine metabolites than most people who crashed in vehicles, Victoria's chief forensic toxicologist Dimitri Gerostamoulos testified.

"I can't come to the conclusion that he was impaired or not. It is likely given the consumption of alcohol and cocaine within that period," said Dr Gerostamoulos, who gave evidence this year at Patterson's Victorian Supreme Court murder trial.

Mr Jenkinson tested negative to alcohol before starting work on the day of the crash and negative at a random drug test in August 2022.

He flew six passenger joy flights and had lunch with workmates before his last and fatal take-off just before 2pm, Ms Lee heard.

Mr Jenkinson's lack of obvious intoxication at that time was not reassuring in itself, Queensland Health senior forensic physician Katherine Robinson testified.

"The subtle and fine signs of impairment are only detected through assessment by people looking to test for them," she said.

Mr Jenkinson signed a form he was fit to fly but might not have been aware of his own impairment, the inquest was told.

Australian Army aviation medical officer Jeffrey Brock said testimony from witnesses about Mr Jenkinson's drug and alcohol use, opportunities for sleep and levels of workplace stress had shifted his opinion.

"To me, the likelihood of impairment during flying on the day of the accident has gone from possibility to probability," Dr Brock said.

But forensic pharmacologist Judith Perl testified Mr Jenkinson's ability to fly being significantly affected before the crash was possible, not probable,

"It would lead me to suspect whatever cocaine he used was pretty poor quality," Dr Perl said.

Mr Jenkinson was killed along with British newlyweds Ronald and Diane Hughes - aged 65 and 67 - and Sydney mother Vanessa Tadros, 36, in the 2023 mid-air collision.

His aircraft collided 25 seconds after take-off with another Sea World Helicopter that was preparing to land at a waterside helipad at the theme park.

Nine passengers across both helicopters were injured.

Sea World owner Village Roadshow Theme Parks sold its joy flights operation to Sea World Helicopters in 2019.

The inquest has been adjourned until January 19, with evidence to resume in February.