ATSB officials have described a flight during which a Robinson R44 crashed into the roof of a Cairns hotel in August this year as "unauthorised and unnecessary".
The pilot took R44 VH-ERH from a hangar at Nautilus Aviation at Cairns Airport in the early hours of 12 August, conducting a low-level flight over Cairns with the strobes turned off. The flight ended when the helicopter collided with the hotel roof in an inverted position. The pilot, a ground employee of Nautilus, was killed in the crash.
ATSB investigators determined that the pilot held a CPL(H), but was not authorised to fly any of Nautilus' aircraft, and was affected at the time by alcohol.
Investigators were unable to state exactly why the pilot took the helicopter and made the flight, only that it was a "purposeful" act.
“The investigation found that the pilot conducted an unauthorised and unnecessary flight at night, while affected by alcohol,” said ATSB Chief Commissioner Angus Mitchell.
“The pilot did not hold the appropriate endorsements to fly at night, did not have any experience flying the R44 at night, and they conducted the flight well below the 1000 ft minimum height for flight over built up areas.”
The ATSB finalised the investigation today after determining it unlikely that broader safety issues or lessons would be uncovered.
“Our final report published today provides assurance to the Cairns community and the aviation industry that after gathering and analysing the available evidence, there are unlikely to be broader transport safety issues that require addressing to reduce future risk arising from this tragic accident,” Mitchell said.
According to the ATSB, the pilot took the helicopter after an evening of drinking and socialising that ended around 2300, but CCTV caught them leaving their apartment just after 0100, and extracting the R44 from the hangar at 0130.
GPS and ATC radar data revealed the aircraft leaving the airport just before 0147, after which the pilot took in on a flight over Cairns, during which it never exceeded 500 feet AMSL.
Two security cameras recorded brief portions of the final part of the flight, showing the helicopter pitching up, then almost immediately descending steeply before colliding into the roof of the hotel at about 0150.
“Wreckage distribution and impact marks indicate that the helicopter was inverted at impact," Mitchell said.
"From the available evidence there were no airworthiness factors with the helicopter that likely contributed to the accident.
“The flight was a purposeful act, but there was no evidence available to explain the pilot’s intentions.”
Most of the helicopter came to rest on the hotel roof and was destroyed by the impact and a post-impact fire.
Parts of the main rotor blade were found in the hotel rooms below the accident site, while the helicopter’s instrument panel, main rotor head, mast and most of the main rotor blades were found in the hotel grounds.
There were no injuries to hotel guests, staff or other people on the ground.
The full report is on the ATSB website, and the ATSB has produced a video explaining how the incident unfolded.