Accident Details
On April 13, 2013, at approximately 1215 mountain daylight time, a Robinson R-44 II helicopter, registration N424DP, serial number 11036, was substantially damaged after impacting terrain near Buffalo, South Dakota. The commercial pilot and three passengers did not report any injuries. The helicopter was registered to Double D Choppers LLC and operated under 14 Code of Federal Regulations Part 91 with no flight plan filed. Day visual meteorological conditions prevailed. The flight originated from private land near Buffalo about 1210.
Flight and Maneuvering
While conducting a sightseeing flight at 100 to 150 feet above ground level and 50 knots airspeed, the pilot reported reversing course from southeast to northwest. After the turn, the low rotor speed horn activated. The pilot lowered the collective and executed an immediate landing into uneven terrain. During the landing, the tail boom and landing gear separated from the fuselage.
Weather Conditions
The weather station at Harding County Airport (K2WX), Buffalo, South Dakota, located 14 nautical miles south of the accident site, reported at 1156: wind 120 degrees at 22 knots with gusts to 28 knots, 10 miles visibility, temperature 8°C, dew point -2°C, altimeter 29.46 inches of mercury.
Postaccident Examination
Following the accident, the engine was functionally tested on the helicopter. It started without hesitation and ran continuously at different power settings, including idle and 100 percent rpm. No anomalies were noted with the engine or its associated controls. Postaccident examination of the airframe and engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation.
Pilot Information
The pilot reported a total flight experience of 12,020 hours, of which 306 hours were in helicopters and 89 hours in this make and model. He was an experienced fixed-wing agricultural spray pilot. On April 5, 2012, he was the pilot of a Robinson R-22 helicopter accident that also involved a low rotor RPM condition and forced landing.
Safety Notice Reference
Review of Robinson Safety Notice SN-18 discussed the issue of overconfidence in pilots transitioning from fixed-wing aircraft to helicopters, highlighting the need for self-discipline and defensive flying.