Aviation safety investigations & reports

Bell 206-B, VH-FHB, 9 km North East of Sydney Airport NSW, 5 August 1984

Investigation number:
Status: Completed
Investigation completed


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The pilot brought the helicopter to a hover at 1000 feet agl, pointing approximately into wind. The aircraft began to yaw to the right and the pilot was unable to stop the resulting rotation. The helicopter descended in a steep nose down attitude and struck the ground heavily while still rotating to the right. The landing skids were torn off and the helicopter came to rest on its left side. No mechanical fault or defect was found with the helicopter which might have contributed to the development of the accident. It was considered likely that the aircraft experienced the phenomenon known as "tail rotor breakaway", which results in an uncommanded yaw to the right accompanied by a steep nosedown pitch change. The pilot was aware of the phenomenon, and had read various articles on the subject. However, much of the information available at the time was of a confusing and conflicting nature, and the recovery action employed by the pilot on this occasion was ineffective.

Download Final Report
[Download  PDF: 22KB]
General details
Date: 05 August 1984   Investigation status: Completed  
Time: 951    
Location: 9 km North East of Sydney Airport    
State: New South Wales   Occurrence type: Loss of control  
Release date: 03 September 1986   Occurrence category: Accident  
Report status: Final   Highest injury level: Serious  

Aircraft details

Aircraft details
Aircraft manufacturer Bell Helicopter Co  
Aircraft model 206  
Aircraft registration VH-FHB  
Type of operation Aerial Work  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point Channel 10 Helipad,  
Departure time 0951  
Destination Channel 10 Helipad, Sydney NSW  
Last update 13 May 2014