NTSB investigators either traveled in support of this investigation or conducted a significant amount of investigative work without any travel, and used data obtained from various sources to prepare this aircraft accident report.
During the 2 to 3 hours before the accident, a witness saw the commercial pilot drinking from a cup that smelled like alcohol and noticed that he refilled the cup two or three times. He then heard the pilot say that he was going to put on an airshow. The helicopter lifted off at a 45° angle backward and upward, reach an altitude of about 125 ft, and then descend out of sight behind hangars. A postaccident examination revealed that the helicopter's tail contacted the ground behind the hangars resulting in separation of both tail rotor blades. The helicopter then rose above the hangars and began to spin. The helicopter descended again, impacted terrain, and burst into flames. The examination of the wreckage did not reveal evidence of any preimpact anomalies that would have precluded normal operation of the helicopter. Toxicology testing detected diphenhydramine, a sedating antihistamine, and elevated levels of ethanol in the pilot's blood and tissues. The pilot was most likely impaired by the combination of ingested alcohol and the use of diphenhydramine, both of which are central nervous system depressants. The impairing effects of the combination of these substances most likely contributed to his decision to fly after drinking alcohol as well as his inability to maintain control of the helicopter.