CEN13FA003 · Bell 407

According to the operator, the pilot was performing a local postmaintenance flight following a routine phase check that had been completed the previous evening. Several witnesses reported seeing the helicopter start up and enter a low altitude hover before it hover-taxied toward the runway. One witness reported that she saw the helicopter depart on the runway heading and disappear into fog or a low cloud ceiling. Another witness, who also was a pilot employed by the operator, reported that there was mist, fog, and a low cloud ceiling when the helicopter departed.

Recovered flight data indicated that, about 20 seconds after takeoff, the helicopter reached a maximum altitude of 255 feet and ground speed of 51 knots while still on the runway heading. The helicopter then entered a left descending turn, during which, it reached a maximum bank angle of 38 degrees to the left and a 20-degree nose-down pitch angle. The helicopter also achieved a 1,600 ft per minute descent during the turn. After turning about 200 degrees from the original departure heading, the helicopter descended into trees and terrain in a nose-low, left-skid-low attitude.

The postaccident examination of the helicopter revealed no evidence of a preimpact failure or malfunction that would have precluded normal operation. Additionally, the engine exhibited damage consistent with it operating at the time of impact. The witness accounts of the helicopter climbing into a low cloud ceiling during initial climb and the subsequent descending left turn shown by the recovered flight data were consistent with the pilot inadvertently encountering instrument meteorological conditions and then attempting a course reversal. Additionally, the helicopter's descent rate and pitch and bank angles during the course reversal were consistent with the pilot lacking a discernible horizon or ground reference to maintain control of the helicopter. Although the helicopter was equipped with basic attitude instrumentation and avionics, it was not certified for flight under instrument flight rules (IFR). Additionally, although he held an instrument rating for helicopters, the pilot was not current for IFR operations nor was it required for his employment as a pilot of helicopters limited to visual flight rules operations.

Verbatim NTSB analysis and probable cause from the NTSB dataset