ERA21LA126

The pilot had been performing low-altitude agricultural operations for about two hours when he heard an aural “chirp” with no associated caution panel lights. After scanning the instruments, he observed nothing abnormal, then immediately the low rotor rpm horn sounded, and the helicopter started to lose altitude as the rotor speed decayed. He briefly observed a red engine light on the instrument panel, and initiated an autorotation from an altitude about 50 ft above the ground and airspeed of about 35 knots. The helicopter landed hard on uneven terrain and rolled over; a post-crash fire ensued. The pilot and passenger egressed without injury. Although examination of the engine and its recovered components revealed no evidence of preaccident mechanical anomalies, the extent of the impact and thermal damage precluded a thorough examination, and the reason for the loss of rotor rpm could not be determined based on the available information.

On February 4, 2021, about 0015 eastern standard time, a Bell 206B helicopter, N820H, was destroyed when it was involved in an accident near Pahokee, Florida. The pilot and passenger were not injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 agricultural flight. According to the pilot, the purpose of flight was to fly at low level above crops, which would allow the helicopter’s downwash to help keep the crops from freezing. After completing about 2 hours of low-level maneuvering, the pilot heard a “chirp” with no corresponding caution panel lights. He scanned the instruments and did not immediately observe anything abnormal, then the low rotor horn sounded, and the helicopter immediately started to lose altitude as the rotor speed decayed. The pilot briefly observed a red engine light on the instrument panel. The pilot initiated an autorotation from an altitude of about 50 ft, and forward airspeed of about 35 knots. The helicopter landed hard on uneven terrain and rolled over. After the helicopter came to rest, a post-crash fire ensued. The pilot and passenger egressed without injury. The pilot reported that, at the time of the accident, there was about 60 minutes of fuel remaining. A Federal Aviation Administration inspector reported that the fuselage, landing skids, engine, and transmission were all located at the main wreckage site, with a portion of the tail boom assembly and a rotor blade found separate from the main wreckage. Significant portions of the helicopter were consumed by the post-impact fire and the engine and transmission assembly was thermally damaged by the post-crash fire. Control continuity could not be established to the main rotor or the tail rotor due to the impact- and thermal-related damage. The fuel system was consumed by post-crash fire; therefore, operation and condition of the fuel system during flight could not be confirmed. The engine and its components were recovered and examined at the manufacturer, which revealed no pre-impact anomalies which would have precluded normal engine operation; however, the examination was limited due to the extent of the thermal and impact damage sustained during the accident.