An investigation into a helicopter crash in Cairns, Queensland, that killed 23-year-old former Christchurch student pilot Blake Wilson in August has uncovered several alarming details, but the reasons behind his actions remain a mystery.

The Australian Transport Safety Bureau has released its final report found that Wilson, employed as ground crew at Cairns Airport, conducted an unauthorized flight in the early hours of the morning.

Despite holding a commercial helicopter pilot license, Wilson lacked the necessary endorsements for night flying and had never flown a Robinson R44 helicopter at night before. The report said he was likely intoxicated when he decided to take the helicopter from his employer’s hangar.

According to his work, Wilson had been celebrating a recent promotion with workmates before taking the helicopter hours later. Using his security code, he gained access to the building and positioned the helicopter on a helipad without activating any strobe lights.

After lifting off from Cairns Airport, he headed south towards the city center. Position data from GPS showed Wilson made a turn over his shared apartment before flying towards the Cairns Wharf complex.

After completing a brief orbit, he continued north along the coastline and eventually returned towards the airport, passing over his apartment a second time. Ground-based radar data indicated that the helicopter maintained an altitude of less than 500 feet throughout the unauthorized flight. While the helicopter’s movements could no longer be tracked by GPS, a CCTV camera captured brief footage of the final moments of the flight.

The video showed the helicopter pitching up before rapidly descending. Within approximately four and a half minutes of takeoff, the helicopter collided with the roof of the DoubleTree Hotel, resulting in a fatal impact and a subsequent fuel-fed fire that destroyed much of the aircraft.

The investigation found that, upon impact, the helicopter was inverted, as evidenced by main rotor blade marks beneath the accident site and the distribution of the wreckage. A portion of a rotor blade shattered a hotel room window, while another part of the blade was discovered in a nearby park. Despite their thorough investigation, the report said there were no mechanical issues with the helicopter that contributed to the accident.

The flight, characterised as an unauthorised but deliberate act, was likely influenced by Wilson’s intoxication. However, officials remain uncertain about why he chose to undertake the fatal flight in the first place.