Accident Overview
On July 29, 2024, at about 1330 central standard time, a Bell 206-B3 helicopter, registration N94XA, was destroyed when it struck powerlines and impacted terrain near Nashua, Iowa. The pilot was fatally injured. The flight was conducted as a Title 14 Code of Federal Regulations Part 137 aerial application operation.
Flight History
According to the operator, the pilot was scheduled to spray insecticide and fungicide over local cornfields. Data from an onboard GPS aerial application guidance system indicated the helicopter departed from a farm approximately 3 statute miles west of Nashua at 0905. It then sprayed several fields south of the accident site. At 1244, the helicopter began a back-and-forth pattern in an east/west direction over a field bisected by a power transmission line. The flight track ceased at 1326:50, about 1,750 feet west of the accident site.
Wreckage and Impact
The helicopter came to rest inverted in a cornfield about 200 feet southeast of a powerline tower, oriented on a heading of 280° true. All major structural components were located at the accident site. The first piece of wreckage found was a section of the main rotor blade afterbody, located about 10 feet east of the powerlines. Two severed powerline conductors were observed near the wreckage; an illegible black and white sticker was removed from the intact west conductor, which sustained abrasion damage.
The airframe was fragmented into multiple pieces consistent with impact forces. The nose section was underneath the main fuselage, and a fracture of the semi-monocoque aft fuselage was found about 40 feet west. The tail boom exhibited several fractures. The upper wire strike cutter showed no evidence of contact, while the lower wire strike cutter showed evidence of wire contact. The main rotor hub and blades were found about 80 feet southeast of the main fuselage, with both blades attached to the hub and spars intact. The mast fractured just below the main rotor hub static contact stop area, consistent with bending overload. The transmission and driveshaft showed overload fractures and rotational contact gouging. The aft tail boom and tail rotor were found about 110 feet east of the main fuselage, with the tail rotor assembly intact and free rotation observed. The airframe did not reveal pre-impact anomalies that would have precluded normal operation.
Engine Examination
The engine was separated between the gearbox and exhaust collector support/hot section. The hot section was about 45 feet from the main fuselage, with extensive crush damage. The compressor and scroll assembly remained attached to the gearbox. All engine mounts were fractured. The KAflex driveshaft remained attached to the freewheeling unit and engine gearbox, but separated at the main rotor transmission. Internal driveshaft and freewheeling unit operated properly when rotated by hand. N1 and N2 continuity were established. Straw-colored fluid with the odor of Jet A1 was found in fuel filters, which contained some foreign material but were not occluded. The engine did not reveal pre-impact anomalies that would have precluded normal operation.
Operator Observations
A representative of the helicopter operator flew a similar Bell 206 along the last known flight path, toward the wires from west to east (090° heading). He reported that the wires were masked by a hill in front of the helicopter’s route and were practically invisible against the background of the cornfield. While flying on the south side of the tree line at spray height, he could not see the transmission tower to his left, and the next tower to his right was out of his field of view.
Additional Information
An automated 911 call was made from the pilot’s iPhone as a result of the impact. The helicopter was recovered and transported to a secure location for further examination.