Executive summary
On 24 February 2013 a Robinson R44 Raven II helicopter operated by Volcanic Air Safaris Limited had just departed on its second scenic flight for the day, with the pilot and three passengers on board, when the engine lost power. The pilot put the helicopter into autorotation and turned the helicopter towards the shoreline, where she carried out a successful ditching in shallow water near the lake edge. The pilot and passengers were able to evacuate the helicopter uninjured. They were picked up shortly afterwards by a nearby jet boat.
The Transport Accident Investigation Commission (Commission) determined that the most likely cause of the engine power loss was a malfunctioning of the engine's right magneto. The malfunction was caused by engine oil that had accumulated in the magneto because an oil slinger had been omitted during a maintenance procedure.
The Commission also found that the imported, second-hand engine and its associated records had not been subjected to the required level of scrutiny before they were released to service, although it is unlikely that this safety issue contributed to the power loss.
This report also comments on how the level of risk to people involved in helicopter operations over water, where there is any chance that a helicopter might have to ditch in water, could be reduced if all occupants were made to wear life jackets.
The Commission made the following recommendations:
- a recommendation was made to the Director of Civil Aviation to provide specific guidance to Civil Aviation Rule Part 145 certified companies, for the performance of conformity inspections of parts and components with unknown service histories or incomplete airworthiness documentation, or that have been stored improperly
- a further recommendation was made to the Director of Civil Aviation to promote the use of quick-donning life jackets for all occupants of single-engine aircraft flying over water
The key lesson learnt from the inquiry into this occurrence was:
- purchasers of aviation parts sourced without the accompanying proper documentation need to research thoroughly the service histories of the components, as do certifying engineers carrying out the required conformity inspections.
Related Recommendations
An engine that had been involved in a sudden stoppage incident overseas was put through a conformity inspection and released to service in New Zealand without the required inspections having been completed. The regulator's guidelines for inspecting used parts of unknown origin was not well defined, and the company's approved procedures developed from these guidelines were not adequate in this case.
Civil Aviation Rule 91.525 requires a life jacket to be available for each person on board a single-engine aircraft being flown beyond the gliding distance from shore. The life jacket is to be stowed in a readily accessible position. The Commission has previously recommended to the Director of Civil Aviation that on all flights, if at any point a ditching is likely to have a better outcome than a forced landing on unfavourable terrain, life jackets should be carried. Helicopters descend at a much higher rate in autorotation than an aeroplane does when gliding.