WPR19TA245

During the flight before the accident, the pilot of the helicopter observed that the engine would not produce adequate power to keep the rotor rpm within the green arc of the tachometer, and witnesses reported hearing backfiring from the engine. The pilot sought the assistance of an acquaintance to help him perform maintenance on the helicopter. The acquaintance told the pilot that he was a commercial pilot with 3,000 hours of flight experience in helicopters, and 300 hours in the accident helicopter make and model. After performing maintenance on the helicopter, they relocated the helicopter to a helipad and boarded the helicopter for flight. The pilot lifted the helicopter to a hover but soon began to have difficulty maintaining control and transferred the flight controls to the passenger. The passenger acknowledged that he had the flight controls. Shortly thereafter, the passenger lost control of the helicopter and it drifted backward into a fuel cart and rolled onto its left side. A postaccident interview and review of Federal Aviation Administration records revealed that the passenger did not possess a pilot certificate. Examination of the airframe revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation. Examination of the engine revealed that the No. 1 cylinder inner and outer intake valve springs were fractured and collapsed, which was likely the cause of the low engine and rotor speed on the previous flight.

On August 27, 2019, about 1716 Pacific daylight time, a Bell 47G-4A helicopter, N6064H, was substantially damaged when it was involved in an accident near North Las Vegas, Nevada. The pilot and a passenger were not injured. The helicopter was operated as a Title 14 Code of Federal Regulation Part 91 personal flight. According to the pilot, he purchased the helicopter in August 2018 and had flown it only twice. On what would have been his third flight, the pilot was air taxiing about 40 knots when he observed that the engine was not generating enough power to keep the rotor speed in the green arc of the tachometer, so he terminated the flight. The pilot reported that witnesses informed him the engine was backfiring during the hovering. The pilot sought assistance from an acquaintance who professed to be a commercial pilot with 3,000 hours helicopter flight experience, and 300 hours flight experience in Bell 47 helicopters. On the day of the accident, the pilot and the acquaintance cleaned and reinstalled the sparkplugs. They then repositioned the helicopter to a helipad with the intent to run the engine and hover over the helipad. The pilot stated that he lifted the helicopter to a hover, and it was difficult to control. He transferred the flight controls to the passenger, believing that he had more flight experience in the helicopter model. The passenger acknowledged that he had the flight controls. According to the pilot, the helicopter “rapidly tipped and tracked backwards to our right toward the parking lot.” Federal Aviation Administration (FAA) inspectors interviewed the passenger, during which he admitted to making false statements of being a certificated pilot. A review of FAA records confirmed that the passenger did not possess a pilot certificate. Review of airport security video revealed that, shortly after takeoff to a hover, the helicopter drifted aft, banked left, and yawed to the right. The tail rotor impacted a fuel cart about the same time that the main rotor impacted the ground. The helicopter then rolled onto its left side. The pilot and passenger exited through the right door with assistance from first responders. Examination of the airframe revealed no preaccident mechanical malfunctions or failures that would have precluded normal operation. Examination of the engine revealed that the No. 1 cylinder inner and outer intake valve springs were fractured and had collapsed, which reduced the height of the springs.