A HELICOPTER pilot sustained a serious head injury in a freak accident, investigators have concluded.

He was struck by a rotor blade while going to help an injured colleague.

The accident investigators have not made any recommendations in relation to the incident in Nelson on May 17 this year.

The aircraft landed at a private site on the Lomeshaye Industrial Estate to drop off two passengers.

The engine power was reduced to flight idle while crew member Harold Lloyd Helm, of Halifax, claimed out to help the passengers.

He was climbing back into the helicopter when he struck his head on the door frame, sustaining a cut that started to bleed, so he walked to the front of the main rotor disc.

The pilot, Roger Feather, of Oxenhope, noticed his colleague's head wound was bleeding heavily and decided to shut down the engine and help him.

But he was struck on the head and seriously injured.

A spokesman for the Department for Transport said: "The helicopter was not fitted with a motor brake. While the main rotor was still slowing down, the pilot disembarked and walked towards his colleague who was standing ahead and just to the right of the nose of the helicopter.

"As the pilot approached the edge of the rotor disc, he was struck on the back of the head by a main rotor blade and sustained a serious head injury.

"It is worthy of note that although the helicopter was fitted with high skids which normally give a minimum rotor tip height of 10ft above the ground, considerable less rotor tip clearance was available during shut down in this case."

The aircraft had landed into the wind and the pilot believed that the addition of a 4ft high earth mound ahead of it caused turbulence which resulted in the main rotor blades sailing as they slowed.