Mustering pilots are reminded to conduct a new risk assessment before commencing unplanned tasks, an ATSB investigation into a May 2021 wirestrike accident highlights.
After two days of wild goat mustering at a property near Hay, New South Wales, the pilot of a Robinson R22 helicopter was instructed to locate a small cattle herd and direct a stockperson to them for mustering to the property’s main yards.
This was first time the main yards were used during the muster. While looking for the herd, the pilot detected a second larger herd and directed the stockperson to the larger herd before heading to locate and move the small herd to the main yards.
After locating the original cattle herd, the pilot began moving them along a fence line towards the main yard and flew ahead and landed to open a gate at the entrance to the yard. They then took-off and flew in a southerly direction—at a height of between 5-10 metres—to another gate that needed to be opened for the cattle. As the R22 turned towards an adjacent gate the helicopter struck an unmarked single wire earth return (SWER) line running across the northern side of the main yards.
Witnesses reported hearing a loud bang, and the helicopter was found on its right side just outside the fence at the north-west corner of the main yards. The helicopter was substantially damaged, with indications it had sustained a wirestrike. The pilot sustained fatal injuries.
“Mustering operations around yards and buildings are inherently dangerous due to low-level hazards including powerlines,” said ATSB Director Transport Safety Stuart Macleod.
“To mitigate the risk of powerlines pilots are reminded that any change to their existing flight or work plan they should conduct a new risk assessment including an aerial inspection to identify potential hazards.”
Powerlines, particularly unmarked wires, can be nearly impossible to see due to the size of the wire, camouflage with the background and the natural limitations of the eye.
“The Aerial Application Association of Australia has been working with landowners and energy suppliers to install markers on powerlines through the Powerline Safety Program. In addition, a number of power companies are making these markers available at reduced cost,” said Mr Macleod.
The ATSB also found the helicopter’s emergency locator transmitter (ELT) did not activate after the accident as it was selected to OFF.
“As the accident was witnessed, this did not affect the response, however, having a working ELT increases the likelihood that an aircraft and its occupants will be located quickly in the event of an accident.”
For more information on how to get powerline markers visit the Aerial Application Association of Australia’s website.