Aviation safety investigations & reports

Loss of control - Robinson R44 helicopter, VH-HFH, Cessnock Aerodrome, NSW, 4 February 2011

Investigation number:
AO-2011-016
Status: Completed
Investigation completed

Safety summary

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What happened

At 1115 Eastern Daylight-saving Time on 4 February 2011, a Robinson Helicopter Company R44 Astro helicopter (R44), registered VH-HFH, commenced circuit operations at Cessnock Aerodrome, New South Wales. On board the helicopter were a flight instructor, a pilot and a passenger.

Following a landing as part of a simulated failure of the hydraulic boost system for helicopter's flight controls, the instructor elected to reposition the helicopter to the apron. As the helicopter became airborne, it became uncontrollable and collided with the runway and caught fire. The pilot exited the helicopter; however, the instructor and passenger were fatally injured.

What the ATSB found

The Australian Transport Safety Bureau (ATSB) identified that a flight control fastener had detached, rendering the aircraft uncontrollable. The helicopter manufacturer had not recorded any previous instances of separation of this fastener. A number of separated components could not be located, preventing the identification of the specific reason for the separation.

A number of human factors contributed to the accident, including that the 'feel' of the flight control fault mimicked a hydraulic system failure.

Finally, the ATSB identified that fatal injuries sustained by the instructor and passenger were due to the post-impact fire and that a large number of R44s had not been modified to include upgraded bladder-type fuel tanks that reduce the risk of post-impact fuel leak and subsequent fires.

What has been done as a result

In response to the identification of a number of failures of the same type of self‑locking nuts in other aircraft, the helicopter manufacturer and Civil Aviation Safety Authority have highlighted the issue to operational and maintenance personnel.

The helicopter manufacturer also reduced the compliance time on a current service bulletin requiring that all‑aluminium fuel tanks fitted to older R44 helicopters be replaced with more impact‑resistant bladder‑type fuel tanks. A second bulletin aimed at removing a possible impact‑related ignition source was also issued.

Safety message

This accident reinforces the importance of thorough inspections by maintenance personnel and pilots. It is also a powerful reminder not to take off after identifying a possible problem with an aircraft. In addition, the accident highlights the risk of carrying unnecessary personnel during practice emergencies, and reinforces the safety benefits of incorporating the requirements of manufacturer's service bulletins in their aircraft as soon as possible.

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Preliminary

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Alternate: [Download  DOC: 514KB]
 

Preliminary report released 18 March 2011

On 4 February 2011, a Robinson Helicopter Company R44 Astro helicopter (R44), registered VH‑HFH, was conducting circuit operations at Cessnock Aerodrome, New South Wales. On board the helicopter were an instructor, a pilot undergoing a helicopter flight review and a passenger.

Following the completion of a sequence involving the simulated failure of the helicopter's hydraulic‑boost system, the instructor assessed that the hydraulic system had actually failed. He elected to reposition the helicopter on the aerodrome to facilitate further examination. Upon becoming airborne, control of the helicopter was lost and it collided with the runway and, shortly after, there was a fire. The pilot managed to exit the helicopter; however, the instructor and passenger were fatally injured.

Examination of the wreckage identified that a bolt securing part of the flight control system had detached. Although the circumstances of the accident are still under investigation, the Australian Transport Safety Bureau has, in the interest of transport safety, issued a Safety Advisory Notice suggesting that operators of hydraulic system-equipped R44 helicopters, and organisations performing inspection, testing, maintenance and repair activities on the flight controls of those helicopters, inspect and confirm the security of the aircraft's hydraulic-boost servos.

Download Preliminary Report
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Alternate: [Download  DOC: 514KB]
 

Safety Issues

Go to AO-2011-016-SI-01 - Go to AO-2011-016-SI-02 -

Self-locking nut failure

A number of self-locking nuts from other aircraft, of the same specification as that used to secure safety-critical fasteners in VH-HFH, were identified to have cracked due to hydrogen embrittlement.

Safety issue details
Issue number: AO-2011-016-SI-01
Who it affects: Owners and operators of Robinson Helicopters
Status: Adequately addressed

Bladder-type fuel tank retrofit

A significant number of R44 helicopters, including VH-HFH, were not fitted with bladder-type fuel tanks and the other modifications detailed in the manufacturer's service bulletin 78 that were designed to provide improved resistance to post-impact fuel leaks.

Safety issue details
Issue number: AO-2011-016-SI-02
Who it affects: Owners and operators of Robinson Helicopters
Status: Adequately addressed
General details
Date: 04 February 2011   Investigation status: Completed  
Time: 1141 ESuT   Investigation level: Complex - click for an explanation of investigation levels  
Location   (show map): Cessnock Aerodrome    
State: New South Wales   Occurrence type: Loss of control  
Release date: 30 April 2012   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Robinson Helicopter Co  
Aircraft model R44  
Aircraft registration VH-HFH  
Serial number 505  
Type of operation Flying Training  
Sector Helicopter  
Damage to aircraft Substantial  
Departure point Cessnock, NSW  
Destination Cessnock, NSW  
Last update 14 November 2018