History of Flight
On January 27, 2014, about 1118 mountain standard time, a Bell model 206L-3 helicopter, registration N207DS, was destroyed when it impacted a wire and terrain near Silt, Colorado. The pilot and two passengers were fatally injured. The helicopter was operated by Delta Bravo Sierra Inc. under 14 CFR Part 135 as an on-demand air taxi flight, conducting aerial surveillance of power transmission lines for Holy Cross Energy. The flight originated from Garfield County Regional Airport (RIL) in Rifle, Colorado, about 1045. Visual meteorological conditions prevailed. The helicopter had completed an earlier surveillance flight and refueled before departing on the accident flight.
The power lines being patrolled ran north-south through a valley. A second set of lines owned by Xcel Energy ran east-west and crossed above the Holy Cross lines. Two parallel static wires ran atop Xcel Energy towers. The helicopter struck the south static wire of the Xcel Energy lines and then impacted the ground. A witness reported seeing the helicopter heading south just before the accident. The Xcel Energy wires were about 170 feet above the valley floor.
Personnel and Aircraft Information
The pilot held a commercial helicopter pilot certificate and a second-class medical certificate issued April 18, 2013, reporting 8,010 total flight hours. The helicopter was a 1991 Bell 206L-3, serial number 51546, powered by a single Rolls-Royce (Allison) Model 250-C30S engine. It had accumulated 5,129.7 total hours as of January 23, 2014. The engine had 12,463.6 total hours and was installed on September 22, 2010.
Meteorological Conditions
Weather at RIL at 1053 included calm wind, 10 statute miles visibility, scattered clouds at 11,000 feet, temperature -2°C, dew point -9°C, and altimeter 30.02 inches of mercury.
Flight Recording
The helicopter carried an infrared camera, two digital video recorders (DVRs), and a GeoStamp+ device. One DVR had an SD card containing video from the accident flight with audio from radio and intercom. Conversation was casual and professional. At 11:15:20, the crew discussed turning right to follow perpendicular power lines. At 11:16:21, deer appeared on the IR camera. At 11:16:29, intersecting power lines came into view; immediately after passing them, video shook, expletives were heard, and recording ended at 11:16:36.
Wreckage and Impact Information
The wreckage came to rest on its left side near crossing power lines. The south static wire of the east-west lines was severed. The main fuselage showed crushing consistent with left-bottom impact. The tail boom separated into two pieces. The landing gear skid tubes and cross tubes were broken. Main rotor blades separated at roots. Control system examination revealed fractures in various components, but no pre-impact anomalies were found. The tail rotor driveshaft cover had marks consistent with main rotor blade impact. The forward fuselage and wire strike cutters showed no evidence of wire impact.
Medical and Pathological Information
A postmortem autopsy determined the pilot's cause of death as multiple injuries consistent with the accident. Toxicology testing was negative for all substances.
Additional Information
The struck power lines were not marked with high-visibility marker balls. Federal obstruction standards (14 CFR 77.23) set a threshold of 200 feet above ground within 3 nautical miles of an airport with a runway over 3,200 feet. The accident occurred about 3.2 nautical miles from RIL (runway 7,000 feet). The wire height was about 170 feet above the accident site elevation. At the time, the sun was about 30° above the horizon at azimuth 162°, with the flight path about 165°, placing the sun directly in front of the helicopter.