A pilot who was killed when he crashed a helicopter into an Australian hotel during an unauthorised flight was under the influence of alcohol at the time, an investigation has found.

The Australian Transport Safety Bureau on Thursday finalised its investigation into the crash in the early hours of August 12.

It’s concluded that 23-year-old pilot Blake Wilson took the helicopter from an airport hangar for an unnecessary and unauthorised flight while affected by alcohol.

Wilson died when the Robinson R44 helicopter crashed into the roof of a hotel in the far northeastern city of Cairns at approximately 2 a.m. local time on August 12.

The crash triggered the evacuation of about 400 hotel guests.

The ATSB found that Wilson, a ground staff employee of the charter company that owned the helicopter, did not have the appropriate experience or licenses for the flight.

“The pilot did not hold the appropriate endorsements to fly at night, did not have any experience flying the R44 at night.

“They conducted the flight well below the 1,000-foot minimum height for flight over built-up areas,’’ ATSB Chief Commissioner Angus Mitchell said in a statement on Thursday.

He said the final report provided assurances to the Cairns community and the aviation industry that were unlikely to be broader transport safety issues.

It needed to be addressed to reduce the risk of future similar incidents.

According to the report, Wilson was socialising and drinking alcohol with friends at various venues in Cairns on the night of August 11.

He returned to his apartment at 11 p.m. local time before driving to his employer Nautilus Aviation’s hangar at Cairns airport at 1 a.m. on August 12.

CCTV footage showed the helicopter took off after 1:30 a.m., flying low over the Cairns central business district, the marina and Wilson’s apartment building for 20 minutes before crashing.

The investigation found the helicopter was inverted when it hit the hotel.

Parts of the rotor blade were found in hotel rooms, with debris strewn across the hotel grounds and street. No evidence was found to explain Wilson’s intentions, and Mitchell said it was fortunate no hotel guests were seriously injured.

 (Xinhua/NAN)