Investigators on Thursday said Blake Wilson, 23, took the helicopter from a far north Queensland airport hangar for an "unnecessary and unauthorised" flight after a night of drinking.
Mr Wilson died when the Robinson R44 helicopter struck the roof of DoubleTree by Hilton in Cairns CBD about 2am in August, prompting the evacuation of about 400 guests.
He was the helicopter's sole occupant.
Blake Wilson died when the helicopter he was flying hit a hotel. (Brian Cassey/AAP PHOTOS)
"There was no airworthiness factor with the helicopter that likely contributed to this accident," Australian Transport Safety Bureau Chief Commissioner Angus Mitchell told reporters.
"The flight was a purposeful act, but there was no evidence available to explain the pilot's intentions."
Witness reports confirmed the pilot had been socialising and drinking alcohol with friends at various venues in Cairns for his farewell party before the crash.
The ATSB says it's fortunate no hotel guests were seriously injured. (HANDOUT/QUEENSLAND POLICE SERVICE)
Mr Wilson returned to his apartment at 11pm before driving to his employer Nautilus Aviation's helicopter hanger about 1am.
CCTV footage showed the helicopter take off after 1.30am, flying for less than 20 minutes before crashing.
Mr Wilson flew the helicopter over the CBD, his apartment building twice and along the marina before heading back towards the city centre.
The flight's last moments caught on CCTV showed the helicopter pitch up before immediately descending steeply into the roof of the hotel.
A report has revealed the pilot was affected by alcohol. (HANDOUT/QUEENSLAND POLICE SERVICE)
Parts of the rotor blade were found in hotel rooms, with other debris strewn across the venue's grounds and on the street.
Mr Mitchell said it was fortunate no hotel guests were seriously injured after two elderly visitors were treated for smoke inhalation.
The report found Mr Wilson did not hold the appropriate qualifications to fly the helicopter at night nor did he have any experience given he flew at just 500 feet over the CBD, instead of the regulated 1000 feet.
Investigators found no evidence to explain the pilot's intentions, Angus Mitchell says. (Brian Cassey/AAP PHOTOS)
"While it was tragic that the young man lost his life, there was significant risk to others here in the Cairns area which is why we have put resources to find out what we can look at all the available evidence," Mr Mitchell said.
"It is fair to say that this is quite an exceptional set of circumstances for the ATSB to be investigating."
24°C