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Summary

Summary

On 25 September 2008, a Bell Helicopter Co 407 helicopter, registered VH-NSH, with a pilot and six passengers onboard, lifted off from the helideck of the cruise ship True North on a 45-minute tourist flight. As the pilot moved the helicopter clear of the right of the ship, and at a height of about 10 m above the surface of the sea, a loud bang was heard followed by a total power loss. The helicopter rapidly descended to the water, where it rolled onto its side before inverting.

Despite two of the occupants, one of whom was unconscious, requiring assistance to exit the partially-submerged aircraft, all of the occupants survived the accident. Sometime later, the helicopter sank.

The investigation found that there had been a 'burst' failure of the engine outer combustion case as a result of ongoing high-cycle fatigue cracking during normal engine operation.

As a result of this occurrence, the engine manufacturer conducted a computerised analysis of the design of the combustion case in an effort to more effectively address the relevant areas of high stress. In response to this, and a similar failure in another helicopter 2 weeks earlier, the Civil Aviation Safety Authority released an Airworthiness Bulletin highlighting the circumstances of the occurrence to Australian helicopter operators.

The operator of the helicopter has also advised its intention to change a number of the operational procedures employed during shipborne helicopter operations to better ensure passenger safety.

 
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