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Analysis

Summary

Risk management options for application during an airborne task include reducing the consequence and/or likelihood of adverse events, such as an aircraft striking a power cable. Those options having the potential to affect the consequence of a wire strike include:

  • the use of helmets and wearing of full-cover clothing by aircraft occupants
  • installation of wire-strike protection systems
  • inclusion of advanced safety harnesses
  • appropriate flight following and search and rescue procedures.

However, in terms of risk, the consequence of an aircraft striking a power cable can generally be expected to be severe to catastrophic. As a result, a large investment is generally made by involved parties in order to decrease the likelihood, and therefore risk of a wire strike. That was the case during the 2004 Plague Locust Control Campaign.

The regulatory requirements affecting aircraft operations below 500 ft above ground level, including in the plague locust aerial support task, were an attempt to reduce the likelihood of an adverse event affecting a pilot during those operations. In addition, the Expression of Interest (EOI) mandated requirements affecting the acceptability of nominated pilots for employment in the locust survey task, indicated an attempt by the NSW Department of Primary Industries (DPI) to further reduce the likelihood of an adverse event during the locust control campaign. Also, the establishment by the operator of specific pilot low-level operations competency requirements defined an additional risk mitigation strategy that was based on the reduction of the likelihood of an adverse event in that environment. Both the DPI and the operator's requirements were in excess of the Civil Aviation Safety Authority regulatory requirements, and were valid risk management options for application in the locust survey task.

It was likely that Rural Lands Protection Boards (RLPBs) relied on the pilot's competence and experiential requirements of the EOI when considering the risks affecting their employees during aerial survey operations. The lack of any local control measure that would have allowed the Forbes or other control centre staffs to ensure that the occurrence and other pilots complied with those requirements meant that the Forbes, and possibly other RLPBs unknowingly placed its employees in a potentially higher risk environment than intended. Similarly, the residual risk inherent in the locust control campaign, including that of a wire strike could have been higher than initially accepted by the State Council in order for the campaign to commence.

The emergency nature of the 2004 locust control infestation resulted in the involvement of DPI and RLPB staff volunteers from throughout NSW in the locust control campaign. In addition, operators and pilots from many backgrounds and experience bases were also involved in that campaign. Those circumstances, together with the 'living' nature of the Standard Operating Procedures (SOP) and, in some instances verbal amendment process minimised the likelihood of the standardisation of airborne techniques and procedures among those operators, pilots and DPI / RLPB staff. That was confirmed in this instance by the recent consideration of whether a survey helicopter needed to land to examine the bands of locusts and the variation in knowledge of the content and application of the SOPs among the DPI / RLPB staff aboard the helicopter.

It was probable that the pilot was unaware of the rear seat occupants' perceived lack of involvement in the identification of power cables or other hazards, or communication equipment difficulties affecting that process. That meant that the identification of any power cables and other hazards effectively rested with the pilot and senior ranger. It was likely that, having drawn the pilot's attention to the wires to the west of the landing area, the senior ranger applied his concentration to the locust band in the paddock once the pilot commenced the final stages of the approach to land. In that case, the identification of the west to east spur line fell to the pilot. Although unable to be quantified, there was the potential that the pilot's workload during the approach to land in the unfamiliar environment adversely impacted on his ability to detect the west to east spur line. The result was that no-one onboard the helicopter detected that spur line.

The abbreviated nature of the pilot's induction meant that the pilot had to integrate relevant aspects of his low flying training and previous experience to the specifics of the locust survey task while carrying out that task. In contrast to the pilot's likely intimate knowledge of the few power cables in the Kununurra area, the density of the power cables in the Forbes area, and the differing environmental and other cues indicating the presence of those cables, suggested that the pilot would have benefited from a practical consolidation of elements of the Chief Pilot's brief. The lack of that practical consolidation had the potential to reduce the reliability of the operator's low-level rating/approval/training requirement as a risk management tool.

Depending on respective pilots' ratings and endorsements, there was a potential difference between survey and spray pilots' knowledge and skills bases affecting the low-level locust control operations. Adherence to the DPI SOP meant that, in the event that a survey pilot did not have an agricultural rating, the pilot may not be able to contribute effectively to the identification and communication of low-level hazards and sensitive areas by an on board ranger or spotter. That could result in the ranger or spotter unwittingly omitting information that was potentially critical to the safe application of relevant chemicals by a spray pilot. Although a spray pilot retained ultimate responsibility for the safety of that application, the investigation concluded that the SOP compounded the risk of an unsafe or environmentally unsound application by a spray pilot.

The SOP requirement for locust survey pilots to fly along creek and tree lines in order to flush up adult locusts could be perceived to represent a form of mustering manoeuvre. Unless included as an individual operator requirement, or an individual pilot held a mustering approval or had completed low-level training, the SOP required pilots to conduct those mustering-like manoeuvres without the benefit of the competency-based mustering risk controls inherent in the requirements of Civil Aviation Order 29.10. In addition, that procedure placed pilots in an environment identified by the Chief Pilot as being particularly dangerous with regard to power cables and other hazards. There was the potential that the SOP manoeuvre requirement could combine with those environmental dangers to increase the likelihood, and therefore risk that a pilot might strike a power cable or other hazard to unacceptable levels.

This investigation identified the potential for the application of relevant risk management strategies to reduce the residual risk affecting a low-level aircraft operation to a level considered acceptable by that operation's stakeholders. The majority of the investment in risk management in that environment was found to be in the reduction of the likelihood of an adverse event. In this occurrence, the lack of a robust application of existing risk controls to the locust survey task resulted in the level of residual risk, including that of a wire strike, being above that intended by the State Council, and considered by respective RLPBs when approving the employment of their staff in airborne operations. The investigation was unable to quantify the contribution of that elevated residual risk to the development of the accident.

 
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