A former theme park assistant has said a rollercoaster ride from which a teenager fell to her death started before she gave a "go" signal.
Rebecca Chittleburgh, 21, also told Haverfordwest Coroner's Court that she should have physically checked safety restraints but had been distracted.
Hayley Williams, 16, of Pontypool, fell 120ft to her death in April 2004.
An expert said aspects of restraints on the hydro ride at Oakwood in Pembrokeshire were "unacceptable".
Ms Chittleburgh said that along with her supervisor she was meant to check the safety restraints before giving him the signal or nod to activate the ride.
She was supposed to physically check the restraints by pulling the seat belts and pushing down the lap bars, and she said she had done this previously that day.
But, she recalled, on the occasion on which Hayley and a group of friends boarded the ride, she was distracted by something going on in the window of the hydro ride station.
When she looked again the carriage was already moving, and she said she had not given the signal to go.
Earlier the inquest was told that footage from the rollercoaster ride moments before Hayley fell to her death suggested a safety bar had not been lowered.
It showed Hayley seat in the ride wearing a yellow plastic poncho to protect her from getting wet as the boat dropped down a near-vertical chute into a plunge pool at 50 mph.
Friend cried out
The jury has heard that the G-force as the boat plunged would have been capable of flipping out anyone who was not secured.
Hayley was dressed in a yellow plastic poncho as she boarded
Hayley's sister Hannah Williams previously recalled that as the ride began to descend, a friend cried out that Hayley had fallen.
Image expert Andy Laws said the image of Hayley was consistent with the T-shaped safety bar on the seat being left "open".
The jury also heard from mechanical engineer Roger Jones, who considered safety to be "unacceptable".
He manually tested all 24 bars and belts and thought they were operating as they should. But, he revealed, he was able to get out of Hayley's seat unaided even after pulling the security lap bar down into place.
"I sat in the seat, pulled the bar towards me and I found that I could get out," he told the inquest. "You are actually able to get out of it."
Mr Jones acknowledged that if the seat belt and the lap bar were both being used - or if either restraint was properly fitted - a passenger would be secure.
Consultant engineer Douglas Dadswell described the double restraint system as "perfectly adequate and standard on many rides at theme parks in the UK".
Later, Oakwood duty manager Simon Phillips recalled how he was alerted to Hayley's fall by a call on his radio.
"As I approached I could see a crowd gathering, I could see someone in the water. My initial thought was someone had jumped in," he said.
Once Hayley was pulled from the water, he said: "We laid her on the gravel and the gentleman did a check for vital signs."
Mr Phillips added that security was called to clear the crowd, an ambulance was summoned and reflective jackets were used to make a landing area for the air ambulance.
An announcement went out on the loudspeaker system for anyone in the park with medical experience and shortly afterwards a triage nurse arrived at the scene.
He said he believed everything that could have been done was done to save her.
The inquest continues.