A motorcyclist suffered fatal head injuries when he crashed into a turning van.
Kulraj Singh Kalsi and his 125cc motorbike were thrown into the air on impact, a coroner heard.
The 23-year-old then struck a metal pillar and a stone gatepost at the entrance to Anchor Mills in Dewsbury.
Despite a swift response from paramedics, he was pronounced dead at the scene at 12.55pm on April 27 last year.
During a hearing at Huddersfield Coroners on Wednesday, witness Simon Furness said he saw the motorbike undertake a Volkswagen Caddy van in Thornhill Road as it was turning into the mill.
“Both the motorcycle and the rider were airborne and then collided with the stone pillar”, he said.
“I would assume he would have seen the van.”
Collision investigator PC Martin Ward said CCTV footage showed van driver John Gledhill had been indicating as he turned.
He said speed had not been a factor in the crash and the primary cause was the bike undertaking the van.
The court heard Mr Kalsi, of West Park Road, Dewsbury, had not been wearing a helmet because of his Sikh religious beliefs.
A post-mortem examination found he died as the result of skull fractures and bruising to the brain.
Det Con Noel Lowden, who rides a motorbike, said it had been drizzling at the time.
He said that with the bike travelling at 35mph and no visor to shield his eyes, there was a chance that Mr Kalsi’s vision was affected.
“It could be a reason why he failed to react to the slowing down of the Caddy,” he said.
Coroner Mary Burke said it was not possible to establish why Mr Kalsi had been riding on the nearside of the van or why he failed to slow down when it began to turn.
She concluded that Mr Kalsi died as the result of a road traffic accident.