Unsecured object lifted by helicopter downwash

The incident occurred when the vessel received the first crew change helicopter of the day. During the final approach of helicopter, the downwash of its rotors caused the cover of the bench to be lifted into the air and flung onto the deck some 6m below. The object was 180 cm x 50 cm. There was no-one in the area where the object landed.

• The bench was recently made onboard.
• The cover of the bench was not secured.
• The Helicopter Landing Officer (HLO) and assistant had both checked the helideck and the area nearby before the first helicopter arrived.
• The immediate cause of the incident was failure to secure the object -the cover of the bench was not secured nor was a requirement for this identified during inspections.
• The root cause of the incident was:
  • Inadequate verification of design – the benches were made for an area affected by downwash during helicopter approach over starboard towards the aiming circle of the helideck. The design of the benches failed to include hinges or securing aids.
  • Failure to identify hazard and risk – during manufacturing, installation of the benches and afterwards during pre-helicopter operation inspections, this hazard and the significant risk it posed, was not identified.

There are a large number of safety flashes in which one of the causes of the incident is failure to secure objects, whether at height or otherwise – for example, the following Related Safety Flash.

IMCA has received no similar incidents involving any objects caught and lifted by helicopter downwash. Keywords used: debris, object, helideck, downwash.