On April 18, 2001, a Hughes 369D (registration N713HT) was involved in an aviation accident near DU Quoin, IL. Investigators recorded the probable cause as: loss of engine power for undetermined reasons, the pilot operating the helicopter outside of the height-velocity curve, and the pilot's failure to maintain control of the helicopter during the emergency landing. This summary draws on records from the U.S. National Transportation Safety Board (NTSB) historical archive.
A helicopter conducting powerline trimming experienced low rotor rpm and engine stoppage, leading to an impact in a corn stubble field. Examination revealed no anomalies.
Accident Sequence
The pilot reported that he was using an aerial saw to side trim trees along a powerline right-of-way. According to the pilot, at the end of the tree line at approximately 150 feet above ground level, he applied power to climb. Immediately, the low rotor rpm horn sounded. The pilot attempted to increase engine and rotor rpm using the governor 'beep switch' and checked the N2/Nr indicators, which showed low 90s. There was no response to the inputs. The pilot then lowered the collective, released the saw, and radioed his ground crew that the engine had stopped. At that point, he had low airspeed, low N2/Nr, and an altitude of approximately 100 feet above ground level. The pilot aimed the aircraft at an open field and tried to gain airspeed to attempt a running landing. The helicopter impacted the field in a near horizontal attitude.
Examination Findings
An examination of the helicopter at the accident site showed the helicopter resting on its left side in a corn stubble field approximately 300 feet south of east-west running power lines, and approximately 730 feet from a clearway of trees where the helicopter was cutting prior to the accident. An examination of the helicopter revealed no anomalies.