On August 15, 2017, a Robinson Helicopter Co R44 (registration VH-HBV) was involved in an aviation accident near Brooklyn (ALA), E 22 km, Julatten, Queensland. No fatalities were reported. Investigators recorded the probable cause as: These findings should not be read as apportioning blame or liability to any particular organisation or individual. The pilot applied aft cyclic just prior to touchdown, resulting in a tail-low attitude. This summary draws on records from the Australian Transport Safety Bureau (ATSB).
A helicopter experienced a tail rotor strike after the pilot applied aft cyclic, causing the tail stinger to be over a slope. The tail rotor separated, leading to a rapid yaw and rollover upon landing.
Incident Description
During a landing approach, the pilot applied aft cyclic just before touchdown, resulting in a slightly tail-low attitude. Normally, the tail stinger would contact the ground to prevent a tail rotor strike. However, the ground behind the concrete landing pad sloped away, placing the stinger over the slope. This allowed the tail rotor to strike the ground and detach without prior warning.
Sequence of Events
Following the detachment of the tail rotor and gearbox, the helicopter yawed rapidly to the right, completing a 360-degree rotation in response to torque from the still-powered main rotor. The pilot did not roll the throttle off quickly enough to reduce the yaw rate before lowering the collective. Consequently, the helicopter was still yawing when the skids contacted the ground. This led to a rollover, and the main rotor blades struck the ground.