An inquest examining the deaths of students Addison Stewart, Chace Harrison, Jye Sheehan, Jalailah Jayne-Maree Jones, Peter Dodt and Zane Mellor resumed in Tasmania on Tuesday.
The kids, all aged 11 or 12, were enjoying end-of-year celebrations at Hillcrest Primary School, Devonport, in December 2021 when a dust devil picked up the castle and other inflatable objects.
The inquest also heard from an employee of the company that set up the equipment, who said he had never been shown an instruction manual and was given "on-the-job" training.
Stephen Fenn, who taught some of the Year 5 and 6 children who died, was supervising near the castle when he felt the wind pick up.
Until then, it had been a sunny day with hardly a breeze.
"I turned around and I could see (the wind) swirling around," the now-retired teacher said.
"As it got close, it increased a little bit and brought up a lot of dust and grass clippings."
The short-lived whirlwind then hit.
"It went from one to 1000 in a split second. To me it felt an awful lot more than 100km/h.
"It could have gone anywhere on that oval. It went straight for the jumping castle, it seemed like."
The veteran teacher heard a "whoosh" sound before seeing the jumping castle come down from the height of a telephone pole and land on the other side of the oval, he said.
He ran to help Jye Sheehan and saw several students lying on the oval, before going to hospital to identify bodies including Addison Stewart's.
"I didn't know she had passed away," he said.
"That was ... very confronting to see that little girl there."
The tragedy forced Mr Fenn, who had taught at Hillcrest since 2000, into an early retirement.
He was unable to return to the classroom with the same care and love, he said.
It affected his mental health, caused depression and meant he was always on the lookout for danger.
The inquest, which began in September after delays due to criminal proceedings, is examining the causes of death, safety protocols and national standards.
Taz-Zorb worker Jesse Barrett, who helped set up the inflatable equipment, said he was never shown an instruction manual but was aware of sewn-on instructions on the castle.
Four pegs were used on the castle's eight tether points, he said.
Taz-Zorb operator Rosemary Gamble would sometimes require more than four pegs, depending on how hard or soft the ground was or whether it was slightly windy, he said.
It was fine, sunny and not windy in the lead-up to the tragedy, Mr Barrett said.
Ms Gamble, who will give evidence on Thursday, claims she was not given a manual by Chinese supplier East Inflatables but downloaded one from its website.
Ms Gamble was found not guilty in 2025 of criminal workplace safety breaches related to the incident.
Earlier, counsel assisting the coroner, Maree Norton, said the castle didn't meet the bar to require registration with workplace regulator WorkSafe Tasmania, and national standards lacked legal teeth.
The inquest continues.
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