Britten-Norman Islander

In an area of rising terrain, the pilot either flew the track in cloud or in markedly reduced visibility, with no reference to terrain, towards steeply rising terrain at an indicated airspeed that was 35 kts above the manufacturer’s (flight tested) promulgated best angle of climb speed to avoid obstacles. There was no evidence of a manoeuvre to avoid the terrain. Furthermore, investigation determined that the aircraft was flown in cloud or in reduced visibility at a cruise climb speed and struck vegetation and the face of a steep ridge resulting in controlled flight into terrain (CFIT). The aircraft was fitted with a Global Navigation System receiver capable of providing visual terrain awareness warnings. It was not fitted with a terrain aural warning interface. Incorporation of an aural warning in conjunction with the visual terrain warning, may have prevented the accident.

Double engine failure in flight caused by a fuel starvation.
The following findings were identified:
• The pilot did not ensure there was sufficient fuel on board for the planned flight from Aneityum to Port Vila.
• When the pilot identified that there was less fuel on board and higher fuel flow than planned, they elected to continue to Port Vila rather than divert to other suitable aerodromes. Having committed to continue, the pilot then did not lean the mixtures or attempt to transfer fuel from auxiliary tanks (unaware the right auxiliary tank contained usable fuel) to increase endurance. As a result, the engines stopped due to fuel starvation, with usable fuel remaining in one auxiliary tank.
• The pilot did not feather the propellers when the engines stopped and did not maintain optimal airspeed in the time between the first and second engines stopping. Thes actions reduced the pilot’s options and resulted in a forced landing into a coconut plantation.
• The chief pilot misunderstood the chief engineer's verbal instructions regarding engine run-in requirements as a need to operate the engine with the mixture at full rich for at least 25 hours. The chief pilot then conveyed this to other company pilots without providing amended fuel flow figures for pilots' use in flight planning.
• High operational tempo in the months leading up to the accident, and the absence of flight crew workload management, increased the risk of fatigue affecting pilot performance. (Safety issue)
• The forced landing was conducted with a tailwind and the pilot did not extend flaps to allow a slower airspeed immediately prior to the collision to reduce impact forces, which increased the injury risk.
• The passenger seats were fitted with lap belts only and no upper torso restraints, increasing the risk of injury during a ground collision.

The ATSB found that the dual engine speed fluctuations and associated power loss was probably the result of fuel starvation. The mechanism was not conclusively determined, however it was identified that the pilot did not operate the aircraft's fuel system in accordance with the aircraft flight manual, and that the configuration and location of the aircraft’s fuel controls and tank quantity gauges were probably not conducive to rapid and accurate interpretation. The aircraft manufacturer released a service letter in June 2022 that detailed an optional modification to centralize the fuel system controls and gauges, however this modification was not fitted to VH-WQA. The ATSB considered that these factors increased the risk of inadvertent fuel tank selection.

The flight crew’s failure to arrest the descent rate during the non-standard approach, which resulted in a hard landing and failure of the right-wing structure. Contributing was the flight instructor’s selection of a challenging approach for initial training.