What happened
On the afternoon of April 18, 1999, a Cessna 206 floatplane, registered ZK-EKJ, was conducting a scheduled scenic flight from Te Anau toward Milford Sound. During the flight, the aircraft collided with the upper portion of a steep, rocky mountain ridge. The impact of the collision resulted in five fatalities, including the pilot and all four passengers on board.
The investigation
Investigators examined the circumstances surrounding the flight path and the pilot's maneuvers near the ridge crest. The inquiry established that the aircraft was flying at a high speed and likely attempted to traverse the ridge at a low altitude. The investigation also looked into the pilot's historical flight patterns and the oversight provided by the aircraft operator. Evidence suggested that the pilot had a history of performing unnecessary low-level maneuvers and crossing ridges with very little clearance during previous scenic flights over several years.
Findings
Several factors contributed to the fatal impact. It is believed the pilot may have miscalculated the elevation of the ridge top, potentially due to distractions or visual illusions. The presence of localized turbulence or downdrafts, combined with the aircraft's high velocity, likely played a role in the accident. The pilot's failure to maintain a sufficient height margin above the ridge crest was a critical factor; had safer ridge-crossing techniques been employed, the collision could have been prevented.
Furthermore, the investigation identified significant organizational failures. The operator failed to provide adequate supervision of the pilot and did not investigate previous reports of low-level flying. Additionally, the operator lacked a formal system to monitor pilot performance or ensure compliance with safety standards. These internal safety lapses, along with the fact that the pilot's previous low-flying incidents were never reported to the Civil Aviation Authority, meant that the risks were never addressed by the regulatory body.
Safety action
Following the investigation, safety recommendations were issued to both the operator's chief executive and the Director of Civil Aviation to rectify the identified safety management and oversight deficiencies.