ERA18LA271

About 1 month before the accident flight, the helicopter, which had not been flown in about 7 years, was fueled with about 40 gallons of fuel, of which 3 gallons were drained to remove potential contamination. The helicopter was flown 1.8 hours between the fueling and the accident flight. There was no record of additional fuel being added between those flights and the accident flight. About 15 minutes after departing on the accident flight, between 500 and 1,000 ft above ground level (agl), the engine lost total power. The pilot performed an autorotation and landed on level, soft terrain, the helicopter tipped forward onto the nose, and the pilot applied aft cyclic to correct. The main rotor blades impacted the tailboom, severing it from the helicopter, and the main rotor transmission and rotor head separated from the mount. The helicopter was not recovered and could not be examined after the accident. The amount of fuel onboard at the time of departure could not be determined. Based on the available information, the reason for the loss of engine power could not be determined.

On September 24, 2018, about 1730 eastern daylight time, a Bell OH58A, N206WH, was substantially damaged when it was involved in an accident near Juana Diaz, Puerto Rico. The commercial pilot and two passengers sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to maintenance records, the helicopter was last operated on September 10, 2011, about 7 years before the accident flight. On August 27, 2018, the helicopter was fueled with about 40 gallons of fuel, then subsequently drained of about 3 gallons to remove any potential contamination. Subsequent maintenance was performed on September 2, 2018, followed by a 1.1-hour test flight and a subsequent .7-hour flight. There was no record of additional fueling between the two dates. The pilot reported that there were no mechanical issues or other anomalies noticed during the previous flights. After conducting the second test flight the morning of the accident, he informed the owner that the helicopter was airworthy, and they could perform the flight. About 15 minutes after departure on the accident flight, between 500 and 1,000 ft above ground level (agl), and with no warning, the engine stopped producing power. The pilot performed an autorotation and landed on level, soft terrain. Upon touchdown the helicopter began to go forward onto its nose, and the pilot applied aft cyclic to correct, which resulted in the main rotor blades impacting the tail boom. The helicopter spun around 180° before coming to rest upright. Examination of the helicopter revealed that the tail boom separated aft of the horizontal stabilizer fins and the transmission and rotor head separated from the mount. The helicopter was not recovered for additional examination or fuel sample collection due to accident site logistics and weather conditions. According to the engine manufacturer, the helicopter’s fuel consumption rate was about 190 pounds (28 gallons) per hour during cruise flight. The helicopter likely consumed about 342 pounds (50 gallons) during the 1.8 hours flight time before the accident flight. The fuel tank had a total capacity of 72 usable gallons. The amount of fuel onboard at the time of departure could not be determined.