What happened
Following a series of successful fishing trips, two helicopters were returning from Pipon Island to Mossman. Due to slow progress caused by prevailing weather, the crew diverted to Cooktown for refueling, landing shortly before nightfall. Although the pilots were only qualified for daylight VFR operations, they departed Cooktown just after last light for the 45-minute journey.
As the flight progressed south, natural light diminished. By 1919 local time, the horizon had become difficult to discern due to the lack of moonlight, low altitude, and potential cloud or rain. While the pilot of YLY attempted to maintain visual references by dimming instrument panel lights, the loss of a distinct horizon made altitude maintenance difficult. After passing Cape Tribulation, the aircraft was operating in dark conditions with minimal terrestrial lighting. Shortly after this point, the Robinson R44 collided with the water in a right skid-low attitude. There were no fatalities reported in this occurrence.
The investigation
The ATSB examined the flight conditions and the pilot's decision-making process. The investigation found that the pilot of YLY was operating outside of their day-VFR qualification. The investigation noted that the pilot's reliance on external visual references—such as the coastline and water surface—became increasingly unreliable as light faded. The pilot's decision to dim cockpit lights to reduce glare further complicated the ability to monitor instruments like the altimeter and vertical speed indicator. Furthermore, the investigation considered that the pilot may have been influenced to continue the flight by the progress of the lead helicopter.
Findings
- The pilot of YLY departed on a night flight despite being only qualified for day-VFR operations.
- Deteriorating visibility and the loss of a visible horizon contributed to the pilot inadvertently allowing the aircraft to descend into the water.
- The pilot's reliance on external visual references was compromised by the transition into night conditions and the lack of artificial or lunar light.
- The pilot's decision-making was influenced by a desire to reach the destination and a potential high tolerance for risk.