NTSB Factual Report

On June 10, 2002, at 0930 mountain daylight time, an Enstrom F-28C, N5694Z, operated by Falcon Helicopter, Inc., and piloted by a commercial pilot, was substantially damaged during a hard landing that occurred 10 miles south of Medicine Bow, Wyoming. Visual meteorological conditions prevailed at the time of the accident. The business flight was for conducting pipeline patrol under the provisions of Title 14 CFR Part 91 without a flight plan. The pilot sustained serious injuries in the accident. The passenger on board the helicopter sustained minor injuries. The flight originated at Laramie, Wyoming, at 0830, and was to terminate at Rawlins, Wyoming .

The pilot reported that he was conducting pipeline patrol and marking the positions of pipeline valves using a global positioning satellite receiver. In his written statement, the pilot said they picked up the pipeline at the northwest side of Laramie and proceeded northwest. "The weather was clear but windy. At about 0930 we made a turn to the west to come around over a location, and continued in the turn back to the east downwind. I rolled out of the turn and started to pull some power for the turn back to the right to pick up the pipeline again when the helicopter yawed right and started losing power." The pilot said he immediately "lowered the collective, added throttle, and turned left to the north." The pilot said he was approximately 100 feet above the ground and had an airspeed of about 60 miles per hour. "With the bank and the autorotation I was able to stop forward motion and ground speed. I flared the helicopter, pulled pitch, and hit flat." The pilot said he shut down the engine after impact. "As far as I could tell the power never came back during the autorotation."

In a subsequent interview, the pilot reported that he had flown to Laramie, from Longmont, Colorado, earlier that morning. At Laramie, the pilot had the helicopter's fuel topped off. The pilot said that the fixed base operator at Laramie, told him that they were having trouble with their refueling truck, but didn't know what that was. The pilot said that the helicopter's attitude during takeoff, climb out, and during the flight to the location where they maneuvered, was level. He said that after completing the turn and on downwind, there was a stiff wind of about 25 knots. The pilot said that he was starting to initiate the turn to get back on the pipeline and was pulling power when the power started bleeding off. The pilot said, "It seemed like it sucked bad fuel."

The helicopter came to rest upright in an open field. A preliminary examination of the helicopter showed the left skid broken upward and the bottom of the fuselage crushed upward. The tail boom was broken off, aft of the baggage compartment. The forward windscreen and chin windows were broken out. The trailing edges of two of the three main rotor blades were bent downward, wrinkled, torn, and twisted. The tail rotor gear box was broken out and found resting on the ground in front of the helicopter cabin. The tail rotor blades were bent outward. The helicopter's engine was retained for further examination.

The National Transportation Safety Board examined the helicopter at Greeley, Colorado, on June 25, 2002. Fuel samples were taken at the sump drains to the left and right fuel tanks, and the fuel strainer. The fuel sample taken from the left tank showed approximately 2 ounces of water. Fuel samples from the right tank and the fuel strainer showed no water. The engine was started and run. No anomalies were found during the engine run. The helicopter was then defueled. Approximately 25 gallons of fuel was drained from the helicopter's two tanks. An additional 4 ounces of water was recovered from the bottom of the helicopter's right fuel tank.

NTSB Probable Cause

the unsuitable terrain encountered during the emergency autorotation, following a partial loss of engine power. Factors contributing to this accident were fuel contamination (water), the low altitude, the high winds, and the tailwind.