What happened
On 27 June 2023, two Robinson R2-2 helicopters were engaged in mustering operations near Limbunya Station in the Northern Territory, working alongside a ground team on motorcycles and horseback. During the operation, the pilot of a second aircraft, VH-RCS, lost contact with the pilot of VH-PSC. After a search lasting approximately 15 to 20 minutes, the second pilot located the wreckage of VH-PSC. The aircraft was destroyed upon impact, and the pilot sustained one fatality.
The investigation
Investigators examined the wreckage to determine the cause of the crash, focusing on a potential reduction in engine power and subsequent loss of control. Analysis of the wreckage suggested the main rotor was in a low energy state at the time of impact. While some minor scoring was found on the drive train belt-tensioning clutch actuator body, the nature of the damage suggested the rotor blades may have been forced backward upon hitting the ground rather than the engine driving the rotation. Furthermore, damage to the fanwheel was consistent with the engine not being operational during the collision.
The ATSB investigated several potential causes for power loss, including mechanical defects, fuel issues, and carburettor icing. No mechanical faults or fuel contamination were identified. Although local meteorological data indicated conditions near the threshold for carburettor icing, the pilot of the nearby aircraft reported no such issues. The investigation also considered whether the pilot had intentionally reduced the throttle for a rapid descent, which could have led to an inadvertent engine stoppage if performed at too low an altitude to execute an autorotation.
Regarding loss of control, investigators found no evidence of bird strikes, wire strikes, or mast bumping. While the possibility of an object in the cabin interfering with controls could not be entirely ruled out, the state of the wreckage prevented a definitive conclusion.
Findings
- The aircraft experienced a reduction in engine power and a subsequent loss of control for reasons that could not be determined.
- The maintenance release for VH-PSC had expired, as there were no endorsements for daily inspections and no certification for completed scheduled maintenance, though this was not a contributing factor to the crash.