Aviation Accident Summaries

Aviation Accident Summary ERA20FA012

New Salem, NC, USA

Aircraft #1

N167AG

Bell 206

Analysis

The pilot was conducting an aerial application flight in the helicopter. During the relocation flight from the previous site, the pilot overflew the application area and a powerline before landing on a truck near the northwest end of the field to refill the helicopter’s chemical reservoir. A witness described a normal liftoff and departure from the truck. The helicopter proceeded north along the west side of the field before turning south, then he heard a “pop” that he attributed to the helicopter striking a powerline wire before he saw the helicopter descend and impact the field. Postaccident examination of the helicopter revealed that a section of a nearby powerline was entangled with the main and tail rotor drive systems, consistent with the helicopter having struck those wires.

Factual Information

HISTORY OF FLIGHTOn October 17, 2019, about 1538 eastern daylight time, a Bell 206B Helicopter, N167AG, was substantially damaged when it was involved in an accident near New Salem, North Carolina. The commercial pilot was fatally injured. The helicopter was operated as a Title 14 Code of Federal Regulations Part 137 local aerial agricultural application flight. According to the operator’s lead ground crew member for the spraying missions on the day of the accident, the pilot performed a preflight inspection of the helicopter about 0745 at their local base. After completing a total of 21 spraying loads at the other locations, the team transitioned to the field where the accident occurred. The ground support truck arrived first and was staged near the northwest corner of the field. The ground crew member reported that the helicopter approached the area from the north, overflew the field to be sprayed, then landed on the truck to refill the chemical reservoir. After refilling, he dispatched the helicopter using hand signals. He reported that the helicopter departed to the north, turned left to a southerly heading, and flew along the west side of the field. Shortly thereafter, he heard a pop that he attributed to a [powerline] wire breaking, then he turned around and saw the helicopter travel about 30 yards before impacting the ground. WRECKAGE AND IMPACT INFORMATIONExamination of the accident site area revealed damage to powerlines that were oriented south to north. (see Figure 1.) The helicopter was on a north-northwest heading when it struck the wire between poles 1 and 2, near pole 2. Figure 1 – Accident location. The helicopter came to rest on its right side, nose low, oriented on a heading of 351°. All major components were located with the main wreckage, with the exception of two pieces. (1) a 9’ 5” section of one rotor blade was located 123 feet to the southwest of the main wreckage. (2) a 12-inch section of the vertical stabilizer was located 198 feet south/southeast of the main wreckage, directly below the wire path between pole 1 and pole 2. The main rotor mast was fractured about 2 inches below the bottom of the hub. The hub and blades were located about 5 feet to the west side of the main wreckage with both blade grips attached and about 3 feet of each blade intact. The left side horizontal stabilizer was fractured from the tail boom and was found next to the tail rotor hub and blade assembly. A section of powerline wire ran from the nose of the helicopter over the top of the cockpit, and about three rotations were wrapped around the main rotor mast and entangled in the spray system. About five rotations of wire were wrapped around the tail rotor hub and blade assembly. The fuel tank bladder remained in place but was breached. The debris field was on a heading of 339° from the vertical stabilizer to the main wreckage. Flight control system continuity was established from the pilot side cyclic and collective controls through the push-pull control tubes to the three hydraulic servo actuators. Continuity was confirmed from the servos through overload breaks in the control tubes to the swashplate assembly on the main rotor mast. The blade pitch change links remained attached at both ends and were fractured consistent with overload. Control continuity was established from the anti-torque pedals to the tail rotor hub and blade assembly. The tail rotor blade pitch change links remained intact and attached. Examination of the throttle linkage confirmed throttle continuity to the engine. The copilot side cyclic and collective controls were not installed. Postaccident examination of the engine, which remained attached to the engine mounts, revealed damage to the compressor air inlet. The compressor blades could not be rotated by hand, and rotational scoring was observed on the top of the air inlet housing.   The main gearbox was found rotated aft about 45°, and the engine to transmission drive shaft was pulled from the main gear box attachment fitting. The main gear box was repositioned upright, and the mast rotated freely by hand. The aft end of the engine to transmission shaft remained attached to the engine reduction gear box. The tail rotor shaft was fractured just forward of the horizontal stabilizer. The shaft remained attached to the engine reduction gear box and showed rotational scoring just forward of the fracture. When the tail rotor shaft was rotated, the freewheeling unit engaged, and when it was rotated in the opposite direction, it turned freely. The shaft aft of the fracture was continuous to the tail rotor gear box, which turned freely when rotated by hand. ADDITIONAL INFORMATIONSpray Information/GPS Data The helicopter was equipped with an AGNAV GUIA Platinum P771 cockpit display recorded data about three times per second and recorded a portion of the accident flight. The device stopped recording about 35 to 40 seconds before the helicopter impacted the electrical wire. According to the operator, “The incident could have been prevented with more thorough field recon” and “more eyes on the site prior to the aircraft arriving.” He also stated that relaying better information to the pilot about the ground conditions could have prevented the accident. MEDICAL AND PATHOLOGICAL INFORMATIONAn Autopsy of the pilot was performed by the Mecklenburg County Medical Examiner’s Office, Charlotte, North Carolina, the pilot's cause of death was blunt trauma injuries of the head and neck. Toxicology testing performed at the FAA Forensic Sciences Laboratory detected no carbon monoxide, volatiles, or drugs.

Probable Cause and Findings

The pilot's inadequate visual lookout, which resulted in impact with a powerline.

 

Source: NTSB Aviation Accident Database

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