At about 1410 EST, on 30 April 2011, the crew of an Aerospatiale AS350FX2 helicopter registered VH-RTV (RTV) was replenishing gas well-head inhibitor tanks using sling load operations from Ballera Airport, Queensland. During one such operation to a well-head that was surrounded by water, the tail rotor blades struck two pipes that extended above the other pipe-work. At the time, the pilot was descending the helicopter prior to releasing the sling. Both he and the crewman were focusing on maintaining clearance from other parts of the well-head and neither saw the two pipes that the tail rotor struck.
Immediately following the occurrence, the operator introduced procedures which specifically addressed inhibitor tank replenishment to supplement the external and sling load procedures which were already in place.