Aviation safety investigations & reports

In-flight break-up involving Cicaré S.A. CH-7BT helicopter, VH-JEW, near Roy Hill Station, Western Australia, on 28 July 2015

Investigation number:
AO-2015-089
Status: Completed
Investigation completed
Phase: Final report: Dissemination Read more information on this investigation phase

Final Report

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What happened

On 28 July 2015, the pilot and owner of an amateur-built Cicaré CH-7BT helicopter, registered VH‑JEW, was conducting a ferry flight from Indee Station to Roy Hill Station, Western Australia. When about 8.5 NM north‑east of Roy Hill Station, the stabiliser assembly fractured leading to an in-flight break up and collision with terrain. The pilot, and sole occupant, was fatally injured and the helicopter was destroyed.

What the ATSB found

The ATSB examined the helicopter wreckage and identified that the stabiliser had separated in‑flight from the tail boom as a result of fatigue cracking of the stabiliser mount. This was the second fatal accident in Australia involving in-flight stabiliser separation on a Cicaré CH-7B helicopter (In-flight break-up involving Cicaré CH-7B, VH-SWQ, 43 km north-west of Barcaldine Airport Queensland on 12 May 2014 (AO-2014-086)). Following the event in 2014, the helicopter manufacturer, Cicaré S.A., released a mandatory service bulletin, BSC007, which required inspection of the stabiliser assembly. However, the bulletin did not include an initial or recurrent time interval for that inspection.

The ATSB found that there were notable differences between VH-JEW and SWQ, and the accidents were not directly comparable. However, it was established that both helicopters were fitted with an external storage pod, likely without the appropriate engineering assessment to ensure there would be no adverse effects on the performance, handling and structure of the helicopter. In addition, both helicopters had previously been used for mustering operations, although the helicopters were designed be used for recreational use only. The ATSB found other Cicaré CH-7B owners were also likely using their helicopters for aerial mustering and other agricultural activities. The addition of unapproved modifications and use for mustering operations can produce unintended stresses on the airframe leading to premature failure of components.

The ATSB determined that a combination of factors could have contributed to the development of the fatigue crack including, the stabiliser design, operating the helicopter in high load mustering activities, and the use of untested accessories. However, the investigation was unable to determine the contribution of these factors.

What's been done as a result

On 6 August 2015, the ATSB emailed an information letter to registered Cicaré CH-7B owners, informing them of the second accident, the mechanism of stabiliser failure, and a recommendation to ensure the integrity of the stabiliser prior to further operation and on an ongoing basis.

The ATSB has also released a Safety Advisory Notice (AO-2015-089-SAN-014) to raise awareness among amateur-built helicopter owners and the aerial mustering community regarding the risks associated with operating outside the recommended design intent.

A revision to the original bulletin, BSC007, was released in September 2015, which provided some additional information with regard to disassembly of the component to allow examination. The contents of this bulletin was incorporated into the ongoing maintenance documentation for the helicopter in March 2016, with the inspection required to be performed every 100 hours. The stabiliser was also redesigned, originally for the bigger CH-8 series helicopter. The latest design was incorporated into all new Cicaré helicopters and is available for retrofit on the CH-7T/B/BT. A number of operators in Australia have already installed the new stabiliser assembly.

Safety message

The addition of external loads may result in forces in excess of the manufacturer’s limitations. This accident highlights the significance of ensuring that any modifications, such as external accessories, are appropriately assessed, and the effects on structural integrity and handling characteristics are considered prior to flight.

Further, it emphasises the importance of operating aircraft in accordance with the manufacturer’s intent and limitations. Operating outside these has the potential to induce stresses on the aircraft, leading to premature wear and possible failure.

Lastly, as detailed in the information letter released in March 2016, the ATSB reinforces the importance of CH-7B owners ensuring the integrity of the stabiliser on an on-going basis. If any doubt arises concerning the inspection or maintenance of any part, piece or component, owners should immediately contact Cicaré.

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The occurrence

Context

Safety analysis

Findings

Safety issues and actions

Sources and submissions

Appendices

Safety Issue

Go to AO-2015-089-SI-01 -

Cicaré S.A. CH-7T/B/BT service bulletin

The Cicaré 7T/B/BT mandatory service bulletin (BSC007) for the general stabiliser support assembly provided limited guidance for disassembly of the manufactured component and did not stipulate a compliance period within which to perform the inspection nor provide consideration for repeat inspections. This potentially reduced the opportunity to detect the presence of crack initiation and growth in the stabiliser support assembly.

Safety issue details
Issue number: AO-2015-089-SI-01
Who it affects: All owners and operators of Cicaré CH7T/B/BT helicopters
Status: Adequately addressed
General details
Date: 28 July 2015   Investigation status: Completed  
Time: 1720 WST   Investigation level: Systemic - click for an explanation of investigation levels  
Location   (show map): 16 km (8.5 NM) NE Roy Hill Station   Investigation phase: Final report: Dissemination  
State: Western Australia   Occurrence type: In-flight break-up  
Release date: 20 December 2019   Occurrence category: Accident  
Report status: Final   Highest injury level: Fatal  

Aircraft details

Aircraft details
Aircraft manufacturer Amateur Built Aircraft  
Aircraft model Cicaré CH-7BT  
Aircraft registration VH-JEW  
Serial number 032  
Type of operation Private  
Sector Helicopter  
Damage to aircraft Destroyed  
Departure point Indee Station, Western Australia  
Destination Roy Hill Station, Western Australia  
Last update 03 April 2020