Plover, WI, USA
N7924S
BELL 47G-3B-1
The pilot reported that the engine was at 3,200 rpm (full power) during takeoff. He completed the last aerial application pass, initiated a climb, and made a 180-degree turn. During the course reversal, the engine power was about 2,000 rpm. He was increasing the power during the rollout when the helicopter descended rapidly and impacted the field. A postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
On July 6, 2013, about 1110 central daylight time, a Bell 47G-3B-1 helicopter, N7924S, sustained substantial during an agricultural aerial application flight near Plover, Wisconsin. The pilot was performing a 180-degree course reversal when the helicopter impacted the terrain. The pilot, the sole occupant, received minor injuries. The helicopter was registered to 102 Leasing LLC and operated by Reabe Spraying Service under the provisions of the 14 Code of Federal Regulations Part 137 as an aerial application flight. Visual meteorological conditions prevailed at the time of the accident, and no flight plan was filed. The flight originated from a private airstrip near Plover, Wisconsin, about 1105. The pilot reported that he was finishing the field after having flown about 5 hours of aerial application flights for the day. On the accident flight, the helicopter was fueled with about 1/2 tank of fuel and about 4 gallons of pesticide. He completed the last pass along the west side of the field traveling to the north. He turned to the southeast and completed spraying a short segment of the field. He pulled up and did a 180-degree turn to the right. During the turn, the engine and rotor rpm were about 2,000 rpm when he started to reapply power. He rolled out of the turn and the helicopter impacted the field. During an interview with a Federal Aviation Administration (FAA) inspector, the pilot reported that the engine was at 3,200 rpm (full power) during takeoff. During the course reversal turn, the engine was about 2,000 rpm, and he was reapplying power back to 3,200 rpm during the rollout when the helicopter impacted the field. FAA inspectors examined the helicopter and determined that the collective, cyclic, and anti-torque pedals exhibited flight control continuity. The examination of the engine's fuel system and ignition system revealed no anomalies. The compression test revealed that all six cylinders had normal compression readings. The main rotor tachometer and engine tachometer were checked and were found operational. A teardown of the engine was conducted and no anomalies were noted which would have prevented normal operation.
The pilot’s failure to maintain proper engine rpm, which resulted in a high rate of descent and ground impact.
Source: NTSB Aviation Accident Database
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