WPR17LA206

The pilot was flying under a powerline during an aerial application flight in an area with which he was very familiar when the helicopter collided with a wire. The wire was installed at a height of about 20 ft on the 40-ft-tall poles and was used for attaching a larger cable data line, which had not yet been installed at the time of the accident. The pilot did not recall seeing the wire before the accident. Examination of the wreckage revealed that the helicopter impacted the wire at its main rotor mast. The main rotor mast separated from the wreckage and the main rotor blades displayed impact damage consistent with ground impact. Examination revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation of the helicopter.

On September 17, 2017, about 0700 Pacific daylight time, a Bell 47G-5 helicopter, N3285T, was substantially damaged when it was involved in an accident near Salinas, California. The pilot received minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 137 aerial application flight. According to the pilot, the accident occurred during his first application pass on the second field of the day. After loading the helicopter with chemicals near the field, he departed and flew around a large power transmission line tower to the east of the field. He planned to fly the first pass from the northeast side and spray the middle of the field to the southwest. He remembered looking for vehicle traffic along the edge of the field before crossing under the smaller power lines supported by 40-ft power poles that ran parallel to the road when the helicopter impacted a wire and, subsequently, terrain. (see Figure 1). The pilot did not recall seeing the wire on the 40-ft power poles before the accident. He further reported that he had been spraying this field for the previous 20 years, and that the weather was not an issue on the morning of the accident. Figure 1-Accident site and approximate flight path. Examination of the helicopter by a Federal Aviation Administration inspector revealed that the main rotor assembly was separated from the helicopter and the main rotor blades exhibited impact damage. Remnants of wire were found wrapped around the main rotor drive shaft. (see Figure 2). The examination of the wreckage revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. Figure 2-Accident site. The large power transmission line towers extended from the southwest to the northeast and paralleled the southeast edge of the field. The 40-ft poles supported power, telephone, and cable lines, and were oriented southeast to a northwest and parallel to the northeast edge of the field. A wire was installed at a height of about 20 ft up the 40-ft poles for attaching a larger cable data line, which had not yet been installed on that section of wire at the time of the accident.