Charter/Taxi (Non Scheduled Revenue Flight)

Controlled flight into terrain (CFIT) after the airplane entered adverse weather conditions while cruising under visual flight rules.
The following contributing factors were identified:
- Deficiencies in the effective control and monitoring of flights by the operations; adequate control or monitoring of the flight by the operator was not evident.
- Deficiencies in dispatch procedures; insufficient provision of preflight meteorological information.
- Deficiencies in the inspection, monitoring, and oversight procedures by the Aeronautical Authority.

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.

Loss of engine power in flight caused by the failure of the exhaust gas temperature regulator (RT12-7 IIc). This led to a subsequent loss of airspeed, a descent, and the aircraft’s collision with trees and the ground.
The accident resulted from a combination of the following factors:
- Violation of the regulator repair procedures.
- Repairs of the regulator were carried out by personnel who did not have specific training.
- The captain failed to check the proper functioning of the temperature regulator after the engine was started, as required by the Aircraft Flight Manual (AFM).

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 pilot's selection of an unsuitable takeoff area, resulting in a loss of directional control. Contributing to the accident was a flooded runway.