20140127000589A

On 01/27/2014 a bht 206 L3 registration # N207DS being operated by delta bravo sierra, inc., the area of operation was the Silt, CO area. The purpose for the operation was power line survey.

At or around 0700 the aircraft was inspected by a certificated mechanic (pre/post flight inspection). While the aircraft was being inspected the camera operator noted an issue with the a/v cable for the flir recording system and replaced the cable the fuel source and the aircraft were sumped and the samples checked for debris and water no evidence of either was reported as observed by the mechanic. These samples are not retained by the operator.

At or about 0900 the PIC took off from the base of operation with 2 passengers on board one from the power company being surveyed and one from a camera operation company used for surveying power lines through the use of specialized video equipment. The reported amount of fuel on board the aircraft was 590LBS and was taken from a fuel trailer at the operator?s facility.

At or around 1030 the aircraft returns to the base of operation. The aircraft takes on fuel and now has a reported 570LBS on board. The aircraft begins a second operation surveying power lines with the same passengers on board. At or around 1118 the aircraft heading south at appx 163°, at GPS 39° 31' 18.54" n , 107° 39' 37.75 w. at this point there is a set of power lines running east to west crossing over the lines being surveyed. There are 2 sets of wires on this tower, there is a set of 3 lower lines running side by side which are considered primary power delivery lines and a 2nd set of 2 higher lines which are considered secondary delivery lines (static). These secondary wires are smaller in diameter than the lower wires and run side by side at approximately the same height there is one on the north side and one on the southern side.

The aircraft strikes the southern secondary line with the main rotor system above the wire strike prevention system. The aircraft crashes 202.12 feet from the point of contact with the power line. Most of the aircraft wreckage is all within an 80' area. The main rotor blades are broken and there are signs of wire abrasion and separation caused by contact with wire cutting through the blade material. The broken portions of the main rotor blades are within 15' of the aircraft. The drive system shows significant evidence of sudden stoppage consistent with power on until point of impact with terrain. The main drive shaft coupling has sheared from the drive flange on the main transmission and the remainders of the drive shafts show signs of torque overload failure. The tail boom has separated from the main fuselage, and is broken into 2 parts one with the vertical fin and t/r g/b attached and the other section has the horizontal stabilizer still attached but the l/h stabilizer has significant damage and is appx 60' from the main wreckage site. The aircraft is destroyed. All personnel on board the aircraft are deceased. There was no evidence at the scene that the aircraft was experiencing any mechanical difficulty up to the point of contact with the wire. At the scene all continuity with the flight controls and engine controls appeared to be severed.

Other pertinent information:

At 1118 the aircraft would have been facing directly into the sun. There was rising terrain at the point contact with the wires. Pilot appears to have attempted to fly between the east west running power lines upper and lower wire sets and struck the southern upper wire with the rotor blades.