Aviation safety investigations & reports

Bell 214ST Helicopter VH-HOQ, Timor Sea, 22 November 1991

Investigation number:
Status: Completed
Investigation completed


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On 22 November 1991 at 0912 hours Australian Central Standard Time (Greenwich Mean Time + 9.5 h), a Bell 214ST helicopter was ditched into the Timor Sea shortly after takeoff from a floating production facility. The two crew and 15 passengers evacuated uninjured from the floating helicopter, prior to the right main flotation bag being punctured and the helicopter capsizing. The report concludes that at a critical stage of the takeoff, at an altitude of approximately 120 ft above the sea, one of the engines experienced a high-side speed excursion. This was followed by an aircraft main rotor speed increase which illuminated a cockpit indication warning that the aircraft main rotor speed was out of limits. The captain reacted to what he thought was an engine power loss by lowering the collective, which is the prescribed response to that situation, thereby unloading the main rotor which rapidly accelerated to 116.7%. The electrical control unit of the ungoverned engine, sensing a power turbine overspeed, actuated the fuel sequence valve to shut off fuel to the engine. As the over speeding engine accelerated, the other engine, while attempting to compensate, decelerated to idle power because of the lowered collective command. The captain's action in lowering the collective exacerbated the rapidity of the event, and because of insufficient aircraft altitude, there was not enough time for the engine still under power to pick up the load, or for the captain to take further corrective action to avoid a sea ditching. At the time of the emergency, the captain was demonstrating a takeoff to his co-pilot.
Download Final Report
[Download  PDF: 2.5MB]
General details
Date: 22 November 1991   Investigation status: Completed  
Time: 0912 ESuT    
Location   (show map): Timor Sea    
State: Western Australia    
Release date: 20 June 1993   Occurrence category: Accident  
Report status: Final   Highest injury level: None  

Aircraft details

Aircraft details
Aircraft manufacturer Bell Helicopter Co  
Aircraft model 214  
Aircraft registration VH-HOQ  
Serial number 28121  
Type of operation Charter  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point Skua Venture  
Destination Troughton Island WA  
Last update 13 May 2014