NTSB investigators say the non- certified pilot, Darren Fenoglio of Montague County, heard a buzzer and saw control panel lights flash before the chopper's engine failed.
The report states one passenger told authorities he had about six beers before the flight, and the other two people had about the same.
The second passenger says they flew for about an hour when the pilot said they should head back to the airport before fuel ran out.
Local authorities reported recovering multiple beer cans and bottles that floated up from the wreckage.
The NTSB report also says both fuel tanks on the chopper were empty.
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