Aviation safety investigations & reports

Collision with terrain, Garlick Helicopters UH-1H, VH-HUE 24 km south-east of Talbingo, New South Wales, on 17 April 2018

Investigation number:
AO-2018-031
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final

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What happened

On 17 April 2018, the pilot of a Garlick Helicopters UH-1H, registered VH-HUE, was conducting long-line lifting operations near Talbingo in the Snowy Mountains region of New South Wales. While on approach to pick-up a load, the helicopter’s engine failed. During the subsequent forced landing, the helicopter collided with trees and a riverbed. The pilot sustained serious injuries and the helicopter was destroyed.

What the ATSB found

The ATSB found that the inner struts in the exhaust diffuser fractured leading to the engine failure. The fracture was the result of high-cycle metal fatigue, which had not been detected for at least 36 routine maintenance inspections prior to the accident. It was also established that the maintenance practices and processes were likely inadequate to detect the potential impending failure of safety critical components. These practices related to inspections, record keeping and trend monitoring.

Following the engine failure, the pilot had limited assurance that ground support personnel could vacate the clearing directly below the helicopter, necessitating a forced landing to a less suitable location. This was likely the result of a risk assessment for helicopter operations that did not consider the hazard of an emergency landing as the helicopter approached to hook-up a load.

The pilot was not wearing the upper torso restraint fitted to the helicopter during the flight. It was virtually certain that this resulted in the pilot sustaining serious head injuries when the aircraft collided with terrain. It was also identified that upper torso restraints were likely not routinely worn by a notable proportion of pilots conducting vertical reference flying operations in Australia. This was likely due to these restraints not being fit-for-purpose for the operations being conducted. The operations mainly related to aerial firefighting, and to a lesser extent, lifting operations.

Although not contributory, the ATSB also found that a screw-clamp was retrofitted to the firefighting retardant delivery hose, which likely prevented the release of the long-line during the forced landing. While this did not influence the outcome of the accident, this had the potential of becoming snagged in trees and increase the severity of the impact. 

Further, the immediate response of the ground personnel to extinguish a small fire in the engine bay and assist the pilot with exiting the helicopter, likely reduced the risk of more severe injuries to the pilot.

What has been done as a result

Following the accident, the maintenance organisation was acquired by another company. They advised improvements were made to their maintenance procedures and processes. Those improvements included the implementation of a new computer-based maintenance system that was expected to provide greater assurance in maintenance performed and assist with trend monitoring for detecting anomalies. Further, vibration test equipment was purchased to allow greater ease in conducting required checks.

In addition, the company responsible for managing the site ground works convened a hazard assessment workshop with the helicopter operators where they reviewed the hazards and controls for mountain flying and lifting operations. This was to ensure alignment, and a common approach and understanding between all parties. A risk management plan was collated during this workshop for use in similar future operations.

Safety message

Purposeful visual inspections of safety critical components, and the routine review of documented maintenance records for trend monitoring and anomaly detection purposes provide a vital role in preventative aircraft maintenance. These aspects would have likely allowed anomalies to be identified and investigated prior to the engine failure occurring.

Helicopter lifting operations introduce additional risks to personnel working in their vicinity. In circumstances where there may be insufficient time to formulate a plan, such as an emergency landing from a low height and low speed, carefully considered and clearly communicated pre‑flight risk assessments provide an important mechanism to mitigate these risks.

Upper torso restraints provide an important defence to reduce the severity of injuries during an accident. This report highlights an elevated risk to pilots who are unable to effectively wear these restraints during some vertical reference operations, such as aerial firefighting and lifting. Further consideration of engineering innovations for these restraints could reduce the risk associated with this problem.

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The occurrence

Context

Safety analysis

Findings

Safety issues and actions

Glossary

Sources and submissions

Appendices

About the ATSB

Preliminary Report

Preliminary report published: 6 June 2018

On 17 April 2018, the pilot of a Garlick Helicopter UH-1H, registered VH-HUE, was conducting long-line lifting operations near Talbingo in the Snowy Mountains region of New South Wales. This operation was part of a proposed expansion of the Snowy Mountains Hydro-electric Scheme, known as the Snowy 2.0 project. The onsite ground crew consisted of two loadmasters, who had VHF/UHF radio communications with the helicopter, and three additional workers.

Figure 1: Accident location of VH-HUE

Figure 1: Accident location of VH-HUE. Accident site location approximately 24 km SSE of Talbingo Township. 
Source: Google Earth

Accident site location approximately 24 km SSE of Talbingo Township. Source: Google Earth

After completing a number of earlier lifts, the pilot was positioning the helicopter to lift the motor of a drill rig. As the helicopter approached, the load master advised by radio that he needed some more time to prepare the rigging for the next lift and requested that the pilot to hold off for a short time. The pilot repositioned the helicopter approximately 700 metres north-east and maintained a hover while waiting for clearance to commence a forward approach to the intended lift. The pilot recalled that weather conditions were ideal in the valley with a slight breeze and good visibility (Figure 2). Wind observations[1] recorded approximately 45 minutes later at Cabramurra (18 km away), were 11 km/hr from the west.

While waiting for radio clearance to lift the drill rig motor, the pilot recalled that he had time to conduct a full systems check and that all instruments indicated the helicopter was operating in the normal range. At about 1415 EST, the load master requested the pilot approach the site in preparation for lifting the drill rig motor. As the pilot approached overhead, the load master radioed to the pilot that he wanted to re-check the rigging and to temporarily delay the approach. In order to minimise the rotor downwash on the people below, the pilot raised the collective to climb the helicopter, and the 100 foot long-line, above the tree canopy.

As the helicopter started to climb, the pilot heard a loud mechanical ‘screaming’ noise, and he started making plans for an emergency landing. Almost immediately, the pilot also heard an audible alarm, followed by a noticeable yaw. Around this time, a light coloured gas or mist was evident near the engine area of the helicopter (Figure 2).

Figure 2: Light coloured gas or mist from helicopter prior to accident

Figure 2: Light coloured gas or mist from helicopter prior to accident. A light coloured mist or smoke is visible trailing from the helicopter in this photograph taken near the time of the ‘Mayday’ call. 
Source: GHD.

A light coloured mist or smoke is visible trailing from the helicopter in this photograph taken near the time of the ‘Mayday’ call. Source: GHD.

The pilot elected to conduct the emergency landing in the Yarrangobilly River bed, south-west of the lifting area and workers. Concurrently, the pilot transmitted a ‘Mayday’ call over the radio. The ground workers observed the helicopter turn to the south-west, away from the lifting site and descend toward the river. The helicopter subsequently collided with the river bed. Two areas along the flight path with broken tree branches were identified, consistent with being struck by the helicopter main rotor blades.

The pilot, who was wearing a helmet and secured in a lap belt, sustained serious injuries and the helicopter was destroyed.

Figure 3: Accident site showing drill pad and helicopter wreckage

Figure 3: Accident site showing drill pad and helicopter wreckage. Drill pad shown in top right of photo including path of helicopter shown. 
Source: GHD.

 

Drill pad shown in top right of photo including path of helicopter shown. Source: GHD.

At interview, the pilot advised he had flared the helicopter prior to the impact with the second tree, but could not recall the remainder of the impact sequence until exiting the helicopter. Examination of the wreckage and ground impact marks indicated that the helicopter had impacted the ground in a nose high, slightly right side down attitude. During the impact with terrain, the tail boom of the helicopter detached from the fuselage. The fuselage then came to a rest inverted and nose low a short distance away, balancing on the main rotor head assembly.

Figure 4: Helicopter wreckage in Yarrangobilly River

Figure 4: Helicopter wreckage in Yarrangobilly River

Figure 4: Helicopter wreckage in Yarrangobilly River. Wreckage of VH-HUE looking downstream away from the drill pad, in the approximate direction of flight. 
Source: ATSB

Wreckage of VH-HUE looking downstream away from the drill pad, in the approximate direction of flight. Source: ATSB

Post-accident response

Four of the workers on the ground gathered fire extinguishers and immediately moved in the direction of the helicopter. One of the loadmasters stayed at the lifting site and called for help via satellite telephone and radio.

The four workers travelled on foot down river to access the accident site. Upon arrival, fuel was visible leaking down the outside of the fuselage. Some smoke was also observed in the area and, due to concerns of a potential fire in the engine bay, fire extinguishers were deployed toward this area to mitigate this risk. Meanwhile, two workers assisted the pilot to exit the helicopter and supported him in moving upstream, safely away from the wreckage, before commencing first aid.

The pilot of another helicopter (also operating in support of the Snowy 2.0 project), heard the Mayday call, flew to the lifting site, and dropped off three additional workers to assist. These workers gathered additional first aid supplies to help provide first aid to the injured pilot and also assisted with rescue coordination. As communication was limited from the site, the pilot of the helicopter took off and climbed the helicopter to relay messages from the ground by flight radio and UHF. This pilot remained overhead for the duration of the rescue efforts and medical extraction of the pilot.

The pilot of a third helicopter (also conducting Snowy 2.0 operations) had also become aware of the accident. This helicopter flew to Cabramurra to transport Snowy Hydro medical support workers to the accident site. Upon arrival at the accident site, the two medical personnel, consisting of a nurse and paramedic, commenced further medical treatment of the injured pilot.

During this time, a medical helicopter was deployed from Canberra to lift the pilot from the site. Approximately 2 hours after the accident, the injured pilot was winched from the accident site and transported to a Canberra hospital.

The immediate rescue efforts of the ground workers afforded the best opportunity to assist the pilot escaping the helicopter, conduct first aid and mitigate the risk of a serious fire.

While the helicopter was destroyed, the fuselage remained unaffected by fire (Figure 5).

Figure 5: Helicopter wreckage showing nose of helicopter in Yarrangobilly River

Figure 5: Helicopter wreckage showing nose of helicopter in Yarrangobilly River. Wreckage of VH-HUE looking upstream toward the drill pad, showing the nose of the helicopter and pilot’s seat. 
Source: ATSB

 

Wreckage of VH-HUE looking upstream toward the drill pad, showing the nose of the helicopter and pilot’s seat. Source: ATSB

Ongoing investigation

Due to the unstable nature of the wreckage, on-site examination was limited. Consequently, the helicopter was lifted from the accident site (Figure 6) and transported by road to a secure hangar for further examination.

Figure 6: Helicopter wreckage lifted to Cabramurra aircraft landing area

Figure 6: Helicopter wreckage lifted to Cabramurra aircraft landing area. Wreckage of VH-HUE being lowered by an s-61 ‘Sea-King’ to Cabramurra ALA for transfer to a secure hangar. 
Source: ATSB

Wreckage of VH-HUE being lowered by an s-61 ‘Sea-King’ to Cabramurra ALA for transfer to a secure hangar. Source: ATSB

The ATSB investigation is continuing and will include the following:

  • Examination of the fuselage, flight and engine instruments, controls and linkages, engine and auxiliary components, and the pilot occupied space.
  • Technical failure mechanisms for the engine and/or drive train
  • Cabin safety and survivability factors
  • Helicopter maintenance history

Acknowledgements

The ATSB wishes to thank the significant contribution of the following organisations and their staff: New South Wales Rural Fire Service, Snowy Hydro Limited, GHD and Jindabyne Landscaping. These organisations assisted with transport to the accident site and operational support during the investigation process. The ATSB also acknowledges the support of Encore Aviation, Charles Taylor Adjusting, Heli Survey Jindabyne and Coulson Helicopters in supporting the lifting of the helicopter wreckage from the accident site.

 

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The information contained in this web update is released in accordance with section 25 of the Transport Safety Investigation Act 2003 and is derived from the initial investigation of the occurrence. Readers are cautioned that new evidence will become available as the investigation progresses that will enhance the ATSB's understanding of the accident as outlined in this web update. As such, no analysis or findings are included in this update.

 

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  1. Source: Australian Bureau of Meteorology

Safety Issues

Go to AO-2021-031-SI-01 - Go to AO-2021-031-SI-02 -

Maintenance practices and processes

Encore Aviation's maintenance practices and processes related to inspections, record keeping and trend monitoring, were likely inadequate to detect the potential impending failure of safety critical components.

Safety issue details
Issue number: AO-2021-031-SI-01
Status: Closed – Adequately addressed

Risk assessment for lifting operations

GHD's documented risk assessment for helicopter operations did not consider the hazard of an emergency landing at the drill site. This increased the risk that ground personnel were not clear of the load pick-up area in the event an emergency landing was required.

Safety issue details
Issue number: AO-2021-031-SI-02
Status: Closed – Adequately addressed
General details
Date: 17 April 2018   Investigation status: Completed  
Time: 1417 EST   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): 24 km south-east of Talbingo, New South Wales   Investigation phase: Final report: Dissemination  
State: New South Wales   Occurrence type: Collision with terrain  
Release date: 16 December 2021   Occurrence category: Accident  
Report status: Final   Highest injury level: Serious  

Aircraft details

Aircraft details
Aircraft manufacturer Garlick Helicopters Inc  
Aircraft model UH-1H  
Aircraft registration VH-HUE  
Serial number 65-09763  
Operator O’Driscoll Aviation Pty Ltd  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Destroyed  
Departure point Lobs Hole, New South Wales  
Destination Lobs Hole, New South Wales  
Last update 16 December 2021