CEN09FA012 · Bell 206 L-4

**This report was modified on June 28, 2010, and May 11, 2015. Please see the public docket for this accident to view the original report.**

The news helicopter was en route to cover a breaking news story. Witnesses saw the helicopter flying approximately 350 feet above the ground when it nosed over and entered a sharp 70-degree bank and dove towards the ground. The helicopter was equipped with a video camera. Analysis of the video revealed a "small perturbation in yaw (nose towards the left) followed by a return back to the right of equal magnitude." The perturbation was "no larger or faster" than other yaw motions seen previously during the flight. About two seconds later, the helicopter began a slow, smooth roll to the right and the ground was no longer visible. The helicopter came down through trees at a 72-degree impact angle. The right skid was embedded in the ground at a 25-degree angle. Both main rotor blades bore evidence of tree strikes. The clevis ends of the pitch change tubes remained attached to their respective horns. The pitch and collective control rods remained attached to their linkages, and the linkages were attached to their respective servos. Flight control continuity was established between the control rods and the servos but could not be established beyond the servos because of impact forces and a postcrash fire. One tail rotor blade was straight and the other blade was bent 90 degrees to the plane of rotation. There was no evidence of a main rotor blade strike against the horizontal stabilizer, synchronized elevator, or finlets or tail boom. Tail rotor continuity was established. Examination of the engine revealed the Pg line was only finger tight. Later pressure testing of the Pg line disclosed no leaks. The transmission, main drive shaft, and freewheeling unit were disassembled and inspected. No anomalies were noted.

The autopsy of the pilot identified areas of moderate to severe (up to 85 to 90 percent) occlusion of the coronary arteries and a small area of scar in the cardiac muscle, but the significance of these findings to the accident could not be conclusively determined. Although it is clear that the pilot had significant coronary disease, which placed him at risk for an acute coronary event, there is no way to determine, on the basis of the available evidence, whether the pilot actually suffered such an event during the accident flight.

The observations from witnesses, analysis of the wreckage and impact evidence, and test results indicated a loss of control occurred. However, the investigation could not determine the reason for the loss of control.

Verbatim NTSB analysis and probable cause from the NTSB dataset