Aviation safety investigations & reports

Wirestrike and collision with terrain involving Robinson R44, VH-HNF 69 km south-east of Hay Airport (Steam Plains), New South Wales, on 31 July 2020

Investigation number:
AO-2020-040
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final

Download Final report
[Download  PDF: 1.99MB]
 

What happened

On 31 July 2020, the pilot of a Robinson R44 Raven I helicopter, registered VH-HNF and operated by Riverina Helicopters, was conducting aerial weed spraying at Steam Plains, 69 km south-east of Hay Airport, New South Wales.

During the fifth spray load of the morning, the pilot turned the spray off and conducted a climb to clear a stand of trees. At 1057 Eastern Standard Time, as the helicopter descended to continue spraying, the top of the left skid struck a powerline that crossed the flight path.

The helicopter entered uncontrolled flight and collided with terrain about 120 m beyond where it struck the wire, resulting in fatal injuries to the pilot. The helicopter was substantially damaged.

What the ATSB found

The ATSB found that the pilot knew the wire existed and overflew a small section of the target area earlier that morning, but did not conduct an aerial inspection to identify hazards and verify the location of the powerline on the accident flight. Without the aerial hazard check, the pilot was reliant on seeing the wire during the flight, but was unable to do so in time to avoid the wirestrike.

The pilot's injuries were consistent with flailing due to the left-side impact, but it could not be determined whether the pilot slipped out of, or was not wearing, the shoulder sash portion of the 3-point harness.

Although the pilot was wearing a helmet, it did not attenuate the impact to survivable levels. Either the impact forces exceeded the helmet design specifications, or the helmet was not fitted, worn or maintained correctly.

The pilot was not effectively managing severe obstructive sleep apnoea, which has been shown can cause impairments in cognitive functions including attention and short-term memory, and increased the risk of the pilot suffering the effects of fatigue. It could not be determined whether the pilot was experiencing any impairments associated with the condition. The condition had also not been disclosed to the Civil Aviation Safety Authority, which prevented oversight of any ongoing safety risk associated with the condition.

What has been done as a result

The ATSB has released a safety advisory notice to strongly encourage pilots conducting low-level operations to wear a flight helmet, ensuring that it is:

  • fit for purpose
  • custom fitted to the pilot’s head
  • properly secured by using the chin strap
  • maintained in accordance with the manufacturer’s instructions.

Safety message

The risk of wirestrike in low-level operations is well-documented. Uncontrolled flight often follows a wirestrike, which increases the risk of serious and fatal injuries. For pilots conducting low-level operations, pre-flight identification of hazards is essential. As more up-to-date mapping and powerlines data is made available, and more wires carry visible markers, pilots have improved access to tools for planning and strike prevention. The ATSB encourages landowners who engage pilots to conduct aerial application operations to mark powerlines that may pose a hazard.  

However, only by conducting an aerial inspection at a safe height, can the pilot be assured of the location of hazards.

Although planning for hazard avoidance is key, pilot limitations remain, including the ability to see a wire or obstacle, attention, memory and distraction. In these situations, survivability features including 4-point pilot seat restraints and flight helmets, significantly improve survivability of helicopter accidents and should be used. It is also important to remember that a helmet will only meet its design specifications if it is fitted properly, worn correctly and maintained in accordance with manufacturer’s instructions.

Common symptoms of obstructive sleep apnoea (OSA) include snoring, excessive daytime sleepiness and poor concentration. It can also have complex and significant physiological, neurological, cognitive and psychological impacts, and increases the risk of accidents. The Civil Aviation Safety Authority’s Obstructive sleep apnoea and aviation safety fact sheet advises pilots who have symptoms of OSA or suspect they may have it, to see a general practitioner. A diagnosis of OSA must be reviewed by a Designated Aviation Medical Examiner.

Download Final report
[Download  PDF: 1.99MB]
 
 
 

The occurrence

Context

Safety analysis

Findings

Safety actions

Sources and submissions

Glossary

Australian Transport Safety Bureau

Preliminary report

Download Preliminary report
[Download  PDF: 315KB]
 

This preliminary report details factual information established in the investigation’s early evidence collection phase, and has been prepared to provide timely information to the industry and public. Preliminary reports contain no analysis or findings, which will be detailed in the investigation’s final report. The information contained in this preliminary report is released in accordance with section 25 of the Transport Safety Investigation Act 2003.

The occurrence

On 31 July 2020, the pilot of a Robinson R44 Raven 1 helicopter, registered VH-HNF and operated by Riverina Helicopters, was preparing to conduct aerial weed spraying at Steam Plains, 69 km south-east of Hay Airport, New South Wales.

Prior to commencing the day’s flying, the pilot briefed with the helicopter owner/operator, who was performing the role of ground crew and responsible for loading the helicopter with chemical. The briefing included a review of the day’s tasking, maps of the property and hazards associated with the operation. The identified hazards included a 19.1 kV single wire earth return powerline, which crossed the property fence line about 5 m above the ground. The powerline had been marked on the pilot’s map during initial planning with the property manager 2 days prior.

The ground crew then loaded the helicopter with chemical from a centrally-located vehicle. According to recorded GPS data from the helicopter, after loading, the pilot flew the helicopter to the property boundary to spray along the fence line, 2.5-5 m above the ground, before returning to the loader (Figure 1). The pilot sprayed four loads over an 80-minute period and departed with the fifth load at about 1050 Eastern Standard Time.[1]

The GPS data showed that the pilot flew the helicopter to the property boundary and began spraying the fifth load. About 350 m before reaching the position where the previously-identified powerline crossed the fence line, the pilot manoeuvred the helicopter to climb over an area of trees 12-15 m high, before descending to continue spraying. During the descent, the helicopter struck the powerline. The electricity provider reported that the fault to the powerline occurred at 1057. This was consistent with the time of the last recorded GPS position, about 300 m prior to the powerline.

The helicopter subsequently collided with terrain about 120 m beyond the powerline, resulting in fatal injuries to the pilot. The helicopter was substantially damaged.

Figure 1: VH-HNF flight path for fifth spray load

VH-HNF flight path for fifth spray load

Source: Google Earth and GPS data, annotated by the ATSB

Site and wreckage examination

The accident site was located in flat and open farmland (Figure 2), about 7 km north-east of the loading vehicle. The ATSB conducted an examination of the site and wreckage, and identified:

  • the main wreckage was located about 120 m beyond the powerline in the direction of travel
  • the powerline remained entangled in the wreckage, with evidence of wire contact on the front of the left skid
  • significant structural deformation, consistent with heavy impact on the left side of the helicopter
  • the helicopter was fitted with bladder fuel tanks, which had ruptured but there was no fire
  • flight control continuity was established
  • there were no pre-existing issues identified with the helicopter that would have precluded normal operation.

Figure 2: Drone image of accident location, taken at 1028 on 4 August 2020

Figure 2: Drone image of accident location, taken at 1028 on 4 August 2020

Source: ATSB

Further investigation

The investigation is continuing and will include:

  • review of pilot qualifications, experience and medical information
  • review of operational procedures
  • review of environmental conditions
  • consideration of powerline visibility
  • examination of survivability aspects
  • review of similar occurrences.

Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties so appropriate and timely safety action can be taken.

A final report will be released at the conclusion of the investigation.

 

__________

  1.  Eastern Standard Time (EST): Coordinated Universal Time (UTC) + 10 hours.
Download Preliminary report
[Download  PDF: 315KB]
 
 
 

Summary

The ATSB is investigating a wirestrike and collision with terrain involving a Robinson R44, VH-HNF, at Steam Plains, NSW, on 31 July 2020.

During agricultural spraying operations, the helicopter struck powerlines and collided with terrain, resulting in substantial damage. The pilot sustained fatal injuries. 

A team of investigators attended the accident site. The evidence collection phase of the investigation will include examination of the wreckage, mapping the site with a UAV, and reviewing documentation and procedures.

A final report will be released at the conclusion of the investigation. Should a critical safety issue be identified during the course of the investigation, the ATSB will immediately notify relevant parties, so that appropriate safety action can be taken.

General details
Date: 31 July 2020   Investigation status: Completed  
Time: 1057 EST   Investigation level: Defined - click for an explanation of investigation levels  
Location   (show map): 69 km south-east of Hay Airport, (Steam Plains)   Investigation phase: Final report: Dissemination  
State: New South Wales   Occurrence type: Wirestrike  
Release date: 04 March 2022   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Robinson Helicopter Co  
Aircraft model R44  
Aircraft registration VH-HNF  
Serial number 2524  
Operator Riverina Rotor Work Pty Ltd  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point Steam Plains, New South Wales  
Destination Steam Plains, New South Wales  
Last update 07 March 2022