What happened
On 23 March 2019 at 1940, a Diamond DA42 aeroplane, registration ZK-EAP, departed Ardmore Aerodrome on an instrument flight rules (IFR) night navigation consolidation flight. On board were a pilot and a safety pilot. The planned route was from Ardmore to Palmerston North, returning via Taupō. The flight south to Palmerston North was uneventful.
After departing Palmerston North at 2135, the pilot received an air traffic control clearance to Taupō via reported waypoints at 9,000 feet. At 2152, the latest Taupō weather was passed: surface wind 030° magnetic at 8 knots, visibility 17 km, overcast cloud at 4,500 feet. The aeroplane left controlled airspace and the pilot switched to Christchurch Information frequency. At 2203, communication was established. At 2205, the aeroplane turned left at TARUA and commenced descent from 9,000 feet, with the pilot reporting 'top of descent'. The flight information officer (FIO) asked about runway lighting. The pilot requested lighting for runway 35 and confirmed conducting the RNAV 35 approach followed by missed approach to Ardmore. The last transmission was at 2212:48.
At 2213, about eight minutes after descent began, the aeroplane struck terrain at about 4,500 feet, approximately 38 km south of Taupō Aerodrome. The pilot and safety pilot were fatally injured. The wreckage was located the following day.
Background
The pilot was a Category B instructor working towards a multi-engine instrument instructor endorsement. The flight was part of the operator's CAA-approved IFR instructor training programme. The safety pilot was also a Category B instructor, accompanying the pilot per operator procedures for IFR training flights. A safety pilot was required to have adequate visibility, a current licence, and type and instrument ratings; the safety pilot on this flight met those criteria. The operator's procedures described the safety pilot as essentially a passenger, not touching controls or radios, but with duties including monitoring for deviations and safety-critical intervention.
The Flight
The pilot booked the flight using the staff rental option the day before. The operator required IFR flights by Category B instructors to be authorised by training management. On the day, a Category A instructor was present but left after completing a training flight; the operations desk remained staffed. The flight to Palmerston North was uneventful. While on the ground, the pilot obtained a clearance from Ōhakea Control for the leg to Taupō. After departure, the pilot climbed to 9,000 feet. The aeroplane was identified and later switched to Christchurch Information. The pilot began descent at 2205. Radar data showed the turn at TARUA. At 2209, the pilot requested runway lighting for runway 35 and confirmed the approach. No further transmissions were received after 2212:48.
Findings
The Transport Accident Investigation Commission found that the pilot descended the aeroplane below the specified minimum safe altitude for the area, and a controlled flight into terrain occurred. The pilot operated outside parameters required for direct routing in uncontrolled airspace when attempting to connect with an instrument approach. No evidence of malfunction or medical issue was found. The aeroplane was equipped with a terrain proximity awareness system, but it was very likely not used. Weaknesses in flight-authorisation procedures permitted the flight without applicable authorisation or supervision. The pilot and safety pilot had little experience in night IFR navigation and required increased supervision.
Lessons
Key lessons include: pilots, especially instructors, should be fully aware of parameters prescribed by Civil Aviation Rules for navigating away from pre-planned and IFR-approved routes; pilots should use and be proficient in the full capabilities of flight instrumentation, including terrain awareness systems and proper lighting; flight training schools should ensure robust flight authorisation and supervision procedures.