Executive summary
Two persons fell while being winched in from the ship "Pacific Ariki", by a hoist installed in Bell 212 helicopter ZK-HNO on 14 November 1993. The ship was at sea 2nm west of Oaonui. The safety issues identified were the effectiveness of the CAA approval of operators and safety audits; the effectiveness of the operators crew training and supervision, the crew's compliance with instructions; the adequacy of existing instructions on winch operation; the dependence of the hoist design on the integrity of the winch cable; the design of hoist control circuitry, and the adequacy of inspection techniques to establish the serviceability of the cable.
Related Recommendations
Require companies engaged in aerial work activities to demonstrate their capability in a different sample of their specialist tasks during consecutive audit inspections.
Investigate the need for and the feasibility of, introducing a suitable maintenance procedure to detect internal wear of winch cables before the cable's strength was reduced to an unacceptable stage.
They review with the subcontracting cable suppliers whether there is a need to impose a life or additional inspections on their winch cables to ensure the sacrificial wear between strands does not jeopardise the safety of winch operations.
When approving an aircraft operating company, encourage that company to have in place a system to ensure that its employees confirm they have read and understood the Operations Manual.
Their cargo winch and rescue hoists be modified so that the control circuitry incorporate a stop switch at the winding in limit which is independent of the control box circuitry.
Amend the Offshore Operations Manual to detail the measures to be taken after a runway situation occurred with a winch. In particular to stress that the winch not be used again until the fault has been rectified by an aircraft maintenance engineer.
Ensure each pilot in his company confirm in writing that the/she had read and understood the contents of the company's Operations Manual(s).
Ensure that helicopter pilots are included in any briefing held about winding exercises or other operations in which they will be involved.