What happened
On 7 March 2000, an Aerospatiale AS 350BA helicopter, registration ZK-HWK, was performing a local charter flight near Raglan, New Zealand. The mission was to transport two telecommunications technicians to the summit of Mount Karioi to service equipment.
Earlier that morning, the flight began in Hamilton under clear skies. However, upon arriving at Raglan, the pilot noted that cloud was already obscuring the upper portion of the mountain. Despite this, the flight proceeded. During the flight toward the summit, the aircraft encountered deteriorating weather. The helicopter eventually struck the forest canopy on the southern side of the mountain before colliding with the ground at an elevation of 1,850 feet. The impact destroyed the aircraft and caused 4 fatalities.
The investigation
Investigators examined the flight path, weather conditions, and the mechanical state of the aircraft. The investigation established that the helicopter was well-maintained, had a valid airworthiness certificate, and was within its weight and balance limits at the time of departure.
While the exact flight path could not be definitively proven, the wreckage trail suggested the aircraft may have been following a ridgeline and inadvertently drifted across a valley. The investigation also looked into the pilot's experience and the meteorological conditions, noting that a low-pressure system was bringing increasing cloud and a lowering cloud base to the coastal area.
Findings
- The aircraft was functioning normally and remained under the pilot's control until the moment of impact.
- The pilot was appropriately licensed and experienced for this type of operation.
- The flight was conducted during a period when local cloud covered the summit of the mountain.
- The pilot may have inadvertently lost visual reference with the ground while flying in reduced visibility.
- There was no significant pressure or pressing reason for the pilot to continue the flight given the obscured summit.
- The location of the Emergency Locator Transmitter (ELT) in the nose of the aircraft was found to be highly vulnerable, which prevented it from functioning after the crash.
Safety action
Following the investigation, a safety recommendation was made to the Director of Civil Aviation to initiate regulatory action. The goal was to require the relocation of ELTs to less vulnerable positions on helicopters, moving them away from the nose section to ensure they remain functional during accidents.