Aviation safety investigations & reports

Sling-load incident involving Aerospatiale Industries AS350, VH-BII, Lake Disappointment, WA, on 23 May 2016

Investigation number:
AO-2016-096
Status: Completed
Investigation completed

Final Report

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On 23 May 2016 at about 0700 Western Standard Time, a team of ground and flight crew commenced sling operations to move a drill rig and associated platform and equipment by helicopter to a new location on a salt lake at Lake Disappointment, Western Australia.

The ground team for the removal of the equipment consisted of a load master and a driller’s offsider. The pilot of an Aerospatiale Industries AS350 helicopter, registered VH-BII, worked with the ground crew to move three mats and a power pack to a new site, before returning to move the rig. The load master and offsider attached the rig to the hook under the helicopter and attached two tag lines – 6 m loop slings, to the load on separate corners. At about 1040, in readiness to lift the rig, the load master advised the pilot using hand signals that the load was attached and that they were clear and ready for the lift.

The helicopter climbed and the rig lifted a few centimetres above the ground. The load swivelled as it lifted off the ground, and pushed against a PVC pipe protruding from a bore hole. The load master and offsider stepped in closer to manoeuvre the rig clear of the pipe.

The pilot observed the ground crew then step away from the rig. As they stepped back, the offsider had inadvertently stepped into the loop of the tag line. As the helicopter lifted the rig, the tag line went taught, and the offsider’s leg was ensnared in the loop. The offsider was lifted off the ground by the leg and the helicopter began lifting the load. The load master radioed the pilot, and advised that the offsider was hanging in the loop.

The helicopter was then about 50–60 ft above the salt lake. The pilot turned the helicopter around to return to the pad and descended to about 15–20 ft above the ground. The pilot also slowed the helicopter as much as possible given the load and the tailwind, to a groundspeed of about 25 kt.

The offsider then freed their leg and was about to jump off, but the helicopter then started to climb and accelerate. The offsider therefore released the tag line and dropped about 10 m into the mud below. The offsider sustained a serious injury.

This incident highlights the importance of conducting a thorough risk analysis prior to commencing operations. The risk assessment should clearly identify hazards and introduce measures that mitigate any associated risks.

 

Aviation Short Investigations Bulletin - Issue 54

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General details
Date: 23 May 2016   Investigation status: Completed  
Time: 10:30 WST    
Location   (show map): Lake Disappointment   Investigation type: Occurrence Investigation  
State: Western Australia   Occurrence type: Miscellaneous - Other  
Release date: 22 November 2016   Occurrence class: Operational  
Report status: Final   Occurrence category: Serious Incident  
  Highest injury level: Minor  

Aircraft details

Aircraft details
Aircraft manufacturer Aerospatiale Industries  
Aircraft model AS.350B2  
Aircraft registration VH-BII  
Serial number 2267  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Nil  
Departure point Newman, WA  
Destination Newman, WA  
Last update 14 November 2018