Casualties unknown

2016-11-12: Robinson Helicopter Co R44 (VH-YMJ) — near Riversleigh (ALA), Queensland

near Riversleigh (ALA), Queensland

On November 12, 2016, a Robinson Helicopter Co R44 (registration VH-YMJ) was involved in an aviation accident near near Riversleigh (ALA), Queensland. Investigators recorded the probable cause as: Insufficient power for the prevailing environmental conditions at the helicopter’s takeoff weight. This summary draws on records from the Australian Transport Safety Bureau (ATSB).

Sourcesthe Australian Transport Safety Bureau (ATSB)Primary reportUpdated 1779789590Data APIEditorial standards

A helicopter with takeoff weight below maximum experienced a forced landing after encountering gusty, variable winds. The investigation determined insufficient power for the environmental conditions at the aircraft's weight.

Background

The helicopter was operated at a takeoff weight below its published maximum takeoff weight (MTOW) and within the limits for hover in ground effect (HIGE) operations. During the takeoff, no unusual noises or vibrations were reported. The engine was delivering power to the rotors, and rotor speed remained within normal limits.

Event Sequence

The pilot estimated a headwind component of 10 knots, but noted that the wind was gusting in strength and variable in direction. Shortly after takeoff, the helicopter was forced to land. The pilot attributed the forced landing to insufficient power for the prevailing environmental conditions at the aircraft's takeoff weight.

Analysis

Two scenarios were considered as possible causes for the insufficient power. In the first scenario, a shift in wind direction to the right of the helicopter would have required increased left tail rotor pedal input to maintain the takeoff heading, thereby reducing the power available from the engine for main rotor thrust. In the second scenario, a decrease in wind strength just after achieving translational lift would have placed the helicopter in the hover out of ground effect (HOGE) flight regime, at the limit for the takeoff weight and ambient temperature.

Findings

The investigation identified that the forced landing likely resulted from insufficient power available for the environmental conditions at the helicopter's takeoff weight. No other factors were identified as contributing to the event.

Probable cause

Insufficient power for the prevailing environmental conditions at the helicopter’s takeoff weight.