Investigation number
198700112
Occurrence date
Location
78km S of Mount Magnet
Report release date
Report status
Final
Investigation type
Occurrence Investigation
Investigation status
Completed
Aviation occurrence category
Loss of control
Occurrence class
Accident
Highest injury level
None

Due to a loose seat belt banging against the fuselage of the helicpoter, the pilot slowed the aircraft and commenced an approach to land as soon as possible. The chosen approach path had a tailwind of between 15 and 20 knots. Shortly after commencing the approach, the rate of descent increased rapidly and the pilot's application of collective pitch to correct the situation further increased the descent rate. During the approach, both the audio and visual annunciators indicated that the engine had failed. The pilot lowered collective but then had to flare as the aircraft was about to impact a small mulga tree. The aircraft cleared that tree but was damaged as a result of a collision with a nearby tree. The rapid rate of descent experienced whilst descending downwind with a low forward speed is typical of an aircraft which has settled in its own main rotor downwash, i.e in a Vortex Ring State. No defect was found in the engine which might have explained the reported engine failure. It is possible that the pilot inadvertantly selected the throttle to the engine shut-off position as he commenced autorotative flight.

Aircraft Details
Manufacturer
Bell Helicopter Co
Model
206
Registration
VH-AZH
Serial number
3075
Operation type
Aerial Work
Sector
Helicopter
Departure point
79km S Mt Magnet WA
Departure time
1053
Destination
78km S Mt Magnet WA
Damage
Substantial