The UH-1H 'Huey' aircraft, operated by Garlick Helicopters, was carrying out long-line lifting operations near Talbingo on April 17, 2018 when its engine failed.

An Australian Transport Safety Bureau (ATSB) report released found the helicopter made a forced landing before colliding with trees and a riverbed.

The pilot suffered serious injuries and the helicopter was destroyed.

The ATSB found the pilot had been wearing a lap-belt and a helmet, but was not wearing the fitted upper torso restraint due to the need to lean out of the aircraft and visibly check the cargo attached below.

"It was virtually certain that this lack of upper torso restraint use resulted in the pilot sustaining serious head injuries when the aircraft collided with the riverbed," ATSB Director Transport Safety Dr Stuart Godley said.

At the time of the crash, Garlick Helicopters was working for Snowy Hydro by moving parts of drilling rigs for a geotechnical survey.

The ATSB investigation found a "notable proportion of pilots" carrying out similar flying operations were likely to not routinely wearing upper torso restraints.

"In the majority of helicopters used for vertical reference flying, the pilot often needs to be able to lean out to look below the helicopter to observe the line and load," Dr Godley said.

"Standard upper torso restraints are likely not fit-for-purpose for these operations. This means, in the event of an accident, the restraints cannot provide the important defence to reduce the severity of injuries.

"Engineering innovations for these restraints could reduce the risk associated with this problem, which is particularly relevant in Australia during bushfire season, when the frequency of vertical reference flying is elevated.

The ATSB also found that two contributing factors for the crash were a lack of prior recognition of the risks posed to the drill site of the helicopter lost power.

The pilot was also unable to get the workers below to clear the drill site and so had to complete an emergency landing.

The pilot did not have assurance that ground support personnel could vacate the drill site in an emergency. As a result, although the engine failed close to the cleared area, the pilot conducted the forced landing to a less suitable location, increasing the severity of impact forces during the subsequent collision with terrain.

Following the crash, Garlick Helicopters has amended its site safety induction to include specific instructions on what to do in an emergency helicopter landing and has engaged a third party 'to review and audit all helicopter operations".