History of Flight
On March 8, 2011, at 1305 mountain standard time, a Hughes 369D helicopter (N131AL) was substantially damaged when it impacted terrain near Meeker, Colorado. The commercial pilot was not injured, and the passenger sustained minor injuries. The helicopter was registered to and operated by Quicksilver Air, Inc., and was conducting a public use deer netting flight for the Colorado Division of Wildlife. The local flight departed approximately 1200 from Meeker, Colorado (KEEO) and operated without a flight plan in marginal visual meteorological conditions.
The pilot reported that the crew was performing their seventh deer capture of the day. While herding a deer toward a road for capture, the pilot descended from 40 feet above the trees using forward cyclic and lowering the collective, with an estimated airspeed of 25 to 30 knots. A shudder or jolt was felt through the helicopter and collective, immediately followed by a "bang," after which the helicopter began rotating right and the nose pitched down. The passenger stated that the helicopter leveled just before impact and then bounced upon hitting the ground, recalling no violent maneuvers before the loud bang.
Personnel Information
The pilot, age 31, held a commercial pilot certificate with airplane single-engine land and helicopter ratings. He was issued a second-class airman medical certificate without limitations on June 24, 2010. The pilot reported 7,600 total flight hours, with 2,420 hours in the accident helicopter make and model. He completed a flight review on November 29, 2010.
Aircraft Information
The accident helicopter was a Hughes 369D (serial number 1107230D) manufactured in 1977, with a standard airworthiness certificate for normal operations. It was powered by a Rolls-Royce 250-C20B turbo-shaft engine rated at 375 horsepower, driving five main rotor blades and a tail rotor through a main gearbox. The helicopter was maintained under a continuous airworthiness inspection program. A 100-hour inspection was completed on February 24, 2011, at an airframe total time of 16,414.7 hours. The helicopter had flown 26.2 hours since the last inspection, with a total airframe time of 16,440.9 hours at the accident.
Meteorological Information
The nearest official weather observation station was Meeker Airport (KEEO), located 25 nautical miles east of the accident site at an elevation of 6,426 feet mean sea level. The METAR issued at 1306 reported wind from 230 degrees at 3 knots, visibility 2 miles in light snow, broken ceiling at 1,400 feet, temperature minus 1°C, dew point minus 4°C, and altimeter 30.00 inches of mercury.
Wreckage and Impact Information
The accident site was in terrain with juniper trees beside a dirt road at an elevation of 6,785 feet mean sea level. The helicopter came to rest on the west side of the road, and the tail boom was found 70 feet away on the east side. The right landing skid separated from the airframe; the left skid was bowed out and partially separated at the front skid leg.
Tests and Research
Investigators from the NTSB, The Boeing Company, MD Helicopters, Inc., an FAA inspector, and a representative from Quicksilver Air, Inc. examined the wreckage. Continuity of cyclic and collective controls was confirmed to the main rotor hub. Chip detectors on the engine were free of contaminants. Battery and trim actuator functional checks revealed no anomalies.
All five main rotor blades were removed for inspection. The yellow blade had a 4.5-inch tear on the trailing edge, 18 inches from the tip, with the metal bent upward. A second partial tear was 5.5 inches from the tip, and a 2.5-inch scratch penetrating to metal with white paint transfer was found 15 inches from the hub. Blue paint transfer and dents consistent with rivet spacing were noted on the leading edge. The blue, white, red, and green blades exhibited wrinkling, bowing, and paint transfers.
The tail boom exhibited torn, bent, and crushed metal at the separation point. Rotational scoring was observed on the tail rotor driveshaft and inner skin. The separated tail boom portion included the aft driveshaft, tail rotor, horizontal and vertical stabilizers, and tail rotor gearbox. The horizontal stabilizer was bent, and the tail rotor driveshaft rotated freely. Continuity was confirmed aside from the separation.
Laboratory examination of tail boom and driveshaft pieces showed overstress separations. The tail boom was deformed at the top lap joint, with blue paint missing and smears. The yellow blade's leading edge abrasion strip had blue paint smears and six indentations matching the tail boom rivet spacing. Damage patterns indicated the yellow main rotor blade impacted the tail boom just left of the top lap joint rivet line, with the blade tip passing under the rivet line aft of the deformation area.
Additional Information
According to MDHI/Boeing, flight tests on all airframes and main rotor configurations have indicated that low rotor rpm is required for blade flexing sufficient to contact the tail boom during normal flight. Historically, main rotor blade contact with the fuselage and tail boom has occurred only with main rotor rpm below the normal operating range or in flight outside the approved operational envelope of the helicopter.