The pilot of a Bell Iroquois that crashed off Anna Bay NSW in 2019 continued VFR flight after last light, according to an Australian Transport Safety Bureau (ATSB) report released today.
Iroquois VH-UVC was en route from Archerfield to Bankstown in September 2019 when it crashed into the sea off Anna Bay. All five occupants of the aircraft died in the accident.
The ATSB investigation found the pilot was not instrument rated and likely encountered dark-night conditions after turning away from the coast, resulting in spatial disorientation that produced a collision with the sea.
"The ATSB found that the pilot continued to fly after last light without the appropriate training and qualifications, and then into dark night conditions that provided no visual cues," said ATSB Chief Commissioner Greg Hood. "That significantly reduced the pilot's ability to maintain control of the helicopter, which was not equipped for night flight.
“Once visual references were lost, the pilot likely became spatially disorientated and lost control of the helicopter, resulting in a collision with water.”
The helicopter had departed that day from Archerfield on a repositioning flight to Bankstown. After refuelling at Coffs Harbour, the crew departed for Bankstown at 4.48pm, which the ATSB determined wouldn't have left enough time for the aircraft to arrive at Bankstown before last light.
The ATSB speculated that as the aircraft got closer to Bankstown, the pilot may have become increasingly committed to continuing with the original plan. Consequently, deciding to turn back or divert may have been perceived as increasingly difficult.
According to the investigation report, the pilot may have had visual cues from ground lighting close to the aircraft’s track as the flight progressed after last light. However, at 6.11 pm the helicopter commenced a left turn and departed the VFR coastal route and tracked offshore on what appeared to be a direct track to Bankstown.
"As the helicopter flew over a featureless sea with overcast conditions blocking out celestial lighting, the pilot likely lost any remaining visual cues and encountered dark night conditions," the ATSB states. "Williamtown ATC radar contact with the helicopter was lost about two minutes later."
"Research has shown that pilots not proficient in maintaining control of a helicopter with sole reference to flight instruments will become spatially disorientated and lose control within one to three minutes after visual cues are lost,” Hood said.
“A VFR flight in dark night conditions should only be conducted by a pilot with instrument flying proficiency as there is a significant risk of losing control if attempting to fly visually in such conditions.
"If day VFR‑rated pilots find themselves in a situation where last light is likely to occur before the planned destination is reached, a diversion or precautionary landing is almost certainly the safest option, or ATC may be able to provide assistance with available landing options.”
The full investigation report is on the ATSB website.