On 10 April 2015, at about 1120 Central Standard Time (CST), the pilot of a Robinson R44 helicopter, registered VH‑LOL (LOL) was engaged in herbicide dispensing operations near Marion Bay on the Yorke Peninsula in South Australia.

In the course of traversing the field at low level in search of the target weed, the helicopter struck a previously unidentified power line severing the tail rotor blade tips. The helicopter was landed safely and the occupants were not injured.

An aerial survey of the area had failed to identify the single wire powerline which was strung between the support posts of two sets of main transmission line running parallel to each other. The single wire dissected the southern edge the operational area and provided power to a distant building. The failure to note the wire was attributed to a lack of readily identifiable support posts and the nature of the reconnaissance flight that served to confirm previously mapped powerlines.

This accident provides a reminder to flight crews of the need for consistency in aerial surveys for powerlines, the establishment of standardised procedures for their identification and the need for independent assessment of their presence.

Single wires can be difficult to see and occur in the most unexpected places in rural areas. ATSB research article ‘Avoidable accidents No. 1 and 2’ provide details on wire hazards associated with flight below 500’ and explains a number of strategies developed by the Aerial Agriculture Association of Australia (AAAA) and the ATSB, to help pilots manage the on-going risk of wire strikes.

Aviation Short Investigations Bulletin - Issue 42

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