Aviation occurrence briefs

Foreign object damage, Eurocopter AS350 B3 Mount Difficult, 38 km south-east of Horsham, Victoria, on 30 June 2021

Status: Completed
Investigation completed


Occurrence Briefs are concise reports that detail the facts surrounding a transport safety occurrence, as received in the initial notification and any follow-up enquiries. They provide an opportunity to share safety messages in the absence of an investigation.

What happened

On 20 June 2021, the Eurocopter AS350 helicopter was involved in lifting operations transporting materials to a worksite on Mount Difficult, approximately 38 km south-east of Horsham, Victoria. The lift operations were conducted by a single pilot, using a 100 ft line, and supported by a second pilot acting as ground crew. The ground crew member was also an experienced long line pilot. The two crew had swapped roles and worked extensively together throughout the project.

The pilot had completed eight lifts that day and at 1350 local time, after all required lifts had been completed, the helicopter returned to the Mount Difficult Helicopter Landing Site (HLS) near the worksite. The landing site was a confined area on the edge of a rock ledge with trees and shrubs nearby (Figure 1). The established procedure was to lower the remote hook and line to the ground before releasing the line from the belly of the aircraft at the lowest safe height. The helicopter would then reposition for an approach. This allowed the helicopter to approach the HLS without the 100 ft line attached.

The pilot placed the line to the south of the HLS and re-positioned to land. Most of the line was lying on the ground, but a small section of the line was suspended in a sapling 10­­­­­–12 ft right front of the aircraft nose. The aircraft landed clear of the line, and after receiving confirmation from the ground crew member that the landing position looked safe, the helicopter was shut down.

As the engine spooled down the ground crew member commenced sorting and coiling the line into the back of the aircraft. This placed tension on the line between the coiled section in the helicopter and the looped section in the tree, thereby bringing the line into the path of the rotor disc. This was caught by a blade and subsequently entangled the rotor head. The line pulled the ground crew member’s arm upwards, snared their lower leg and body, before pulling them sideways along the ground.

The crew member sustained minor bruising to their face, right elbow, left leg and foot and was later cleared of concussion or serious injury. The line was later found to have wrapped around the mast, resulting in minor damage to the swashplate, mast, rotor head and main rotor blades.

Figure 1: Mount Difficult HLS

Figure 1: Mount Difficult HLS

Source: Supplied by operator, annotated by the ATSB

Safety action

The ATSB has been advised the operator has implemented the following safety action in response to this occurrence:

  • A safety briefing was conducted with all company pilots, which included an incident analysis, review of procedures and safety measures. A new requirement was introduced that now states that objects should not be raised above shoulder height while under the rotor disc.
  • The Flying Operations Manual and relevant Aircraft Operations Plans (including Daily Safety Briefing and Emergency Plan) were updated to specifically clarify that:
    • movement of equipment, including aerial work equipment, into and out of aircraft should be conducted while the rotor is stationary unless strictly necessary; and
    • coiling of lines and the assembly of equipment must be completed outside the rotor disc unless the rotor is completely stationary.

Safety message

Despite having produced detailed safety assessments and extensively documented operating procedures, an unintentional decision error resulted in a serious incident. Operators involved in complex operations need to remain vigilant when monitoring potential hazards around the area of operations, especially when equipment is to be stored or positioned close to operating aircraft.

About this report

Decisions regarding whether to conduct an investigation, and the scope of an investigation, are based on many factors, including the level of safety benefit likely to be obtained from an investigation. For this occurrence, no investigation has been conducted and the ATSB did not verify the accuracy of the information. A brief description has been written using information supplied in the notification and any follow-up information in order to produce a short summary report, and allow for greater industry awareness of potential safety issues and possible safety actions.

General details
Date: 30 June 2021   Investigation status: Completed  
Time: 1350 EST    
Location   (show map): 38 km south-east of Horsham    
State: Victoria    
Release Date: 12 November 2021   Occurrence category: Serious Incident  
Report status: Final    

Aircraft details

Aircraft details
Aircraft manufacturer Eurocopter  
Aircraft model AS350 B3  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Minor  
Departure point Mount Difficult, Victoria  
Destination Mount Difficult, Victoria  
Last update 12 November 2021