LAKE KACHESS, WA, USA
N2062D
Bell 206 B3
While conducting long-line operations, the helicopter experienced a sudden loss of engine power and the pilot initiated a forced landing to a nearby road. Post accident examination of the helicopter revealed that the helicopter was not equipped with an engine air induction system deflector kit (snow baffles). The FAA approved Rotorcraft Flight Manual for the helicopter (Limitations Section) states, in part, the following: "The following equipment shall be installed when conducting flight operations in falling and/or blowing snow to reduce the possibility of engine flameout: The Particle Separator Engine Air Induction System Kit and the Deflector Kit." The 0956 METAR observation at Stampede Pass (approximately 4 miles northeast of the accident site; elevation 3,800 feet above mean sea level [MSL]) reported winds from 090 degrees at 5 knots; visibility 1/4 statute mile, heavy snow and freezing fog; broken clouds at 300 feet; overcast at 1,400 feet; temperature dew point 18 degrees F; and temperature 16 degrees F. Post accident inspection of the engine revealed no evidence of a mechanical failure or malfunction.
On November 23, 2000, about 0945 Pacific standard time, a Bell 206 B3, N2062D, sustained substantial damage following a sudden loss of engine power, autorotation, and forced landing near Lake Kachess, Washington. The helicopter is owned and operated by Aero-Copters, Inc, of Seattle, Washington, and was being operated on a visual flight rules (VFR) long-line operation under the provisions of Title 14 CFR Part 133 when the accident occurred. Visual meteorological conditions prevailed and a company flight plan was on file. The commercial pilot, the sole occupant of the helicopter, was not injured. There was no fire. The flight originated from a service area near the accident location approximately 35 minutes prior to the accident. In a written statement to the NTSB, the pilot reported that he was on the 85th lift of the day, and he was preparing to release a load of pine boughs from the helicopter's 40-foot long-line when he "... heard the engine spool down [and] (quit)" at an altitude of approximately 85 feet above ground level (AGL). The pilot reported that he initiated a right turn, reduced collective, and initiated a forced landing to a nearby service road. On November 29, investigators from the National Transportation Safety Board, Federal Aviation Administration, and Rolls-Royce Corporation inspected the helicopter at Aero-Copter's hangar facility in Seattle, Washington. The helicopter's airframe was intact; however, damage was noted to the skids and front cross tube assembly. Rearward and upward crushing was noted to the forward lower portion of the helicopter's fuselage. Deformation to the top of the fuselage, below the transmission, was noted. The main rotor assembly was intact and there was no visible damage to the main rotor blades. The aft portion of the fuselage, forward of the tail boom attach point, was buckled. The tail rotor drive assembly and rotor blades were intact and no damage was noted. Further examination of the helicopter revealed that the helicopter was not equipped with an engine air induction system deflector kit (snow baffles) part number 206-706-136-001. External examination of the engine (Rolls-Royce 250-C20B) revealed no evidence of pre or post-impact damage. Control continuity from the pilot controls to the engine and engine accessories was established. At the conclusion of the inspection, the helicopter's engine was removed and shipped to Acro Aerospace, Inc, Richmond, BC, Canada, for additional inspection and test run. On December 30, the helicopter's engine was inspected by personnel from the Transportation Safety Board of Canada and Rolls-Royce Corporation at the Acro Aerospace facility in Richmond, BC. After the initial inspection, the engine was placed in a test cell, and a normal engine start was conducted. Subsequent to the engine start, normal engine operations were verified at idle, take-off and cruise power settings. During the initial engine inspection at Acro Aerospace, two small screws were found trapped in the bleed air line forward of the anti-ice poppet valve. A representative from Rolls-Royce identified the screws as originating from the seat attachment for the anti-ice valve. Test data supplied by the engine manufacture indicates that two screws lodged in the bleed air line could result in a 34% reduction of bleed air flow in the left anti ice line, and a 0-15% overall reduction of bleed air to the entire engine anti-ice system (report attached). The 0956 METAR observation at Stampede Pass (approximately 4 miles northeast of the accident site; elevation 3,800 feet above mean sea level [MSL]) reported winds from 090 degrees at 5 knots; visibility 1/4 statute mile, heavy snow and freezing fog; broken clouds at 300 feet; overcast at 1,400 feet; temperature dew point 18 degrees F; and temperature 16 degrees F. The FAA approved Rotorcraft Flight Manual for the Jet Ranger (Limitations Section) states, in part, the following: "The following equipment shall be installed when conducting flight operations in falling and/or blowing snow to reduce the possibility of engine flameout: The Particle Separator Engine Air Induction System Kit and the Deflector Kit".
The pilot's failure to comply with the flight manual regarding the use of an induction system deflector kit (snow baffles) while operating in snow, and the ingestion of foreign material/snow that resulted in an engine flameout while hovering. A snow baffle deflector kit not being installed and snow are factors contributing to the accident.
Source: NTSB Aviation Accident Database
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