The Australian Transport Safety Bureau (ATSB) has released its investigation report into the crash of a VFR Cherokee 235 off Point Lonsdale in Victoria last year.
VH-PXD with four people on board was part of a group flying from Moorabbin to King Island on 29 January 2016 when it crashed into Bass Strait after encountering bad weather. There were no survivors.
The aircraft tracked from Moorabbin over Port Phillip Bay before turning through 180 degrees, then heading south over the strait. After two minutes, it turned right again before entering a steep descent and impacting the water.
Cameras in the area and the weather radar showed poor visibility at the time, and another aircraft had already returned to Moorabbin, later reporting what appeared to be storms over Point Lonsdale. Two other aircraft from the same group passed through the area minutes later, reporting poor conditions, but both were able to continue to King Island.
"... continuation of the flight beyond Point Lonsdale, and towards an area of low visibility conditions, was likely influenced by the inherent challenges of assessing those conditions," the ATSB investigation report states.
"The ATSB also found that due to the presence of low cloud and rain, the pilot probably experienced a loss of visual cues, and became spatially disoriented, leading to a loss of control and impact with the water. The risk of loss of control in the conditions was increased by the pilot's lack of instrument flying proficiency."
The report also examines the pilot's decision to depart from Moorabbin under what were then Special VFR conditions, and the influences on the pilot's assessment of the weather.
The ATSB also issued a caution that "on entering an area of reduced visual cues, the risk of experiencing spatial disorientation and a loss of control is high, measuring from between 60 to 178 seconds from the time of entering the area of low visibility. This risk is highest for those without proficiency or recent experience in instrument flying. Requesting assistance from air traffic control can increase the chances of re-establishing visual cues."
The full investigation report can be downloaded from the ATSB website.