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

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

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.

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.