Robinson Helicopter Company R44 II N4124D accident near Blackwell, Texas

Probable cause

The pilot’s failure to maintain proper altitude and clearance during low-level aerial application, resulting in an in-flight collision with power lines.

NTSB analysis

During an aerial application flight, the helicopter impacted power lines that were near the top of the canopy of a mesquite tree grove. The helicopter was destroyed during the impact. No radio or distress calls were heard from the pilot before the collision. Detailed examinations of the flight controls, airframe, and engine did not reveal any preimpact mechanical malfunctions or failures that would have precluded normal operation. Examination of the engine revealed multiple transfer marks and scoring consistent with engine rotation at the time of impact.

The pilot's toxicology results indicated that he had used a cannabis product. The precise timing of his cannabis use, and whether he was experiencing impairing effects from that use at the time of the accident, could not be determined from available evidence. Thus, it is unknown whether effects of the pilot's cannabis use contributed to the accident. The pilot's autopsy identified mild coronary artery disease and mild left ventricular hypertrophy of the heart. This heart disease conveyed some increased risk of a sudden impairing or incapacitating cardiac event, such as heart attack or abnormal heartbeat. Based on available medical evidence, it was unlikely that the pilot's mild heart disease contributed to the accident.

Text from the NTSB. Open the NTSB docket for CEN22FA288 for the full record.