What happened
While attempting to land on a pontoon at Hardy Reef, the pilot of an EC1ly0B helicopter, registered VH-WII, initiated a go-around after a message appeared on the engine display. During this maneuver, the aircraft experienced an unexpected and rapid yaw to the left. The pilot was unable to arrest this movement, causing the helicopter to descend and strike the water. Following the impact, the aircraft rolled to the right and the cabin became submerged. The accident resulted in two fatalities among the five occupants.
The investigation
The investigation examined several factors that reduced the safety margin during the approach. The aircraft was operating near its maximum weight, having departed Hamilton Island approximately 25 kg over the limit due to inaccurate weight assessments. Additionally, the engine power output was near the minimum allowable limit for this type, and the pilot was using high power to maintain a slow approach to disperse birds from the landing site.
Investigators also looked into the flight dynamics of the turn. The pilot was performing a left turn into a 20-knot right crosswind. While this technique was standard for the operator to reduce required pedal input, it increased the risk of an uncontrolled left yaw. The investigation found that during the go-around, the pilot likely failed to apply sufficient right pedal to counteract the developing yaw, leading to the sudden loss of control.
Findings
- The pilot had limited experience on the EC120B, with only 11 hours of command time on the type.
- The aircraft was operating at a high power setting, near the maximum continuous power limit.
- The decision to perform a left turn into a right crosswind increased susceptibility to an unanticipated yaw.
- The pilot experienced high workloads during the final approach and the subsequent go-around.
- Inaccurate passenger and cargo weight assessments contributed to the aircraft being overweight at departure.
- There were deficiencies in the operator's processes for managing birdstrike risks and ensuring pilot skill consolidation on new aircraft types.
- Emergency egress was hindered by inadequate passenger briefings and the complex design of the aircraft's rear exit.