Aviation safety investigations & reports

Bell 206B, VH-AZH, 78km S of Mount Magnet WA, 10 November 1987

Investigation number:
Status: Completed
Investigation completed


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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.

Download Final Report
[Download  PDF: 22KB]
General details
Date: 10 November 1987   Investigation status: Completed  
Time: 1055    
Location: 78km S of Mount Magnet    
State: Western Australia   Occurrence type: Loss of control  
Release date: 08 August 1988   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Bell Helicopter Co  
Aircraft model 206  
Aircraft registration VH-AZH  
Serial number 3075  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point 79km S Mt Magnet WA  
Departure time 1053  
Destination 78km S Mt Magnet WA  
Last update 13 May 2014