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Location:
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Montrose, Colorado
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Accident Number:
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CEN25LA003
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Date & Time:
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October 2, 2024, 18:40 Local
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Registration:
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N656RB
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Aircraft:
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Schweizer 269C
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Aircraft Damage:
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Substantial
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Defining Event:
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Loss of engine power (total)
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Injuries:
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2 Minor
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Flight Conducted Under:
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Part 91: General aviation - Personal
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Analysis
The pilot stated that during an autorotation demonstration, the helicopter exhibited a complete loss of engine power. The pilot had set up the demonstration about 1,500 ft above ground level and about 60 knots indicated airspeed with hard packed gravel chosen for the touchdown point. The pilot stated that the engine rpm went to zero as soon as he rolled off the throttle to start the autorotation. He attempted to restart the engine with no success and conducted an autorotation to the predetermined touchdown area. During the ground run, the left skid collapsed and the helicopter rolled onto its left side, which resulted in substantial damage to the main rotor system, tail boom, and tail rotor system.
An examination of the engine revealed no evidence of mechanical malfunctions or failures that would have precluded normal operation. The engine was started multiple times and ran through various rpm settings. Both fuselage fuel tanks were intact and contained fuel consistent with 100LL Avgas.
Discussions with the pilot revealed that he had recently purchased the helicopter and was now operating it in high elevation areas. Review of the rotorcraft flight manual revealed a required check of the idle mixture, idle speed, and fuel boost pump at the end of the last flight of each day. When interviewed, the pilot stated that he had never performed this check, did not witness the owner perform the check, and was not taught to perform the check during his initial flight training in the make and model helicopter 12 years earlier.
According to the airframe manufacturer, failure to perform the idle check can allow an improperly adjusted idle speed, throttle linkage, or air-fuel mixture setting to go undetected. Under those conditions, rolling the throttle to idle or a rapid power reduction—such as during a
simulated autorotation—can result in the engine rpm decaying below sustainable idle limits, leading to a total loss of engine power.
Based on available evidence, it is likely that the air-fuel mixture or idle setting had not been adjusted for flight operations in the high elevation area and went undetected due to the pilot’s failure to perform the required post flight check.
Probable Cause and Findings
The National Transportation Safety Board determines the probable cause(s) of this accident to be:
A loss of engine power during a demonstrated autorotation due to an improperly adjusted air-fuel mixture or idle setting. Contributing to the accident was the pilot’s failure to perform the required idle check during previous flights in higher elevation areas.
Findings
Factual Information
History of Flight
On October 2, 2024, about 1840, mountain daylight time, a Schweizer 296C helicopter, N656RB, was substantially damaged when it was involved in an accident near Montrose, Colorado. The pilot and passenger sustained minor injuries. The helicopter was operated as a Title 14 Code of Federal Regulations Part 91 personal flight.
The pilot stated that during an autorotation demonstration the helicopter had a complete loss of engine power. The pilot had set up the demonstration about 1,500 ft above ground level and about 60 knots indicated airspeed with hard packed gravel chosen for the touchdown point.
The pilot stated that the engine rpm went to zero as soon as he rolled off the throttle to start the autorotation. He attempted to restart the engine with no success and conducted the autorotation to the predetermined touchdown area. During the ground run, the left skid collapsed and the helicopter rolled onto its left side, which resulted in substantial damage to the main rotor system, tail boom, and tail rotor system.
Discussions with the pilot revealed that he had recently purchased the helicopter and would operate it around Montrose, Colorado, at high elevation. Review of the rotorcraft flight manual revealed a required check of the idle mixture, idle speed, and fuel boost pump before the end of the last flight of the day. When interviewed, the pilot stated that he had never performed this check, did not witness the owner perform the check, and was not taught to perform the check during his initial flight training in the make and model helicopter 12 years earlier.
According to the helicopter manufacturer, in the Schweizer 269C, failure to perform the idle check can allow an improperly adjusted idle speed, throttle linkage, or air-fuel mixture setting to go undetected. Under those conditions, rolling the throttle to idle or a rapid power reduction—such as during a simulated autorotation—can result in the engine rpm decaying below sustainable idle limits, leading to a total loss of engine power.
The purpose of the idle check is to ensure that when the pilot rolls the throttle to the idle detent or rapidly reduces power the engine continues to operate at the prescribed idle speed without stalling or dropping below the minimum rpm. The check also verifies proper idle air-fuel mixture and confirms that the engine can accelerate smoothly back to operating rpm when power is reapplied. For those reasons, the manufacturer considers the procedure a mandatory operational verification item.
The helicopter’s maintenance logbooks were not made available for review.
Pilot Information
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Certificate:
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Commercial; Flight instructor
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Age:
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43,Male
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Airplane Rating(s):
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None
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Seat Occupied:
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Left
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Other Aircraft Rating(s):
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Helicopter
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Restraint Used:
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4-point
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Instrument Rating(s):
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Helicopter
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Second Pilot Present:
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No
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Instructor Rating(s):
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Helicopter; Instrument helicopter
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Toxicology Performed:
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|
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Medical Certification:
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Class 2 Without waivers/limitations
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Last FAA Medical Exam:
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April 9, 2024
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Occupational Pilot:
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Yes
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Last Flight Review or Equivalent:
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February 8, 2024
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Flight Time:
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4044 hours (Total, all aircraft), 3984 hours (Pilot In Command, all aircraft), 62 hours (Last 90 days, all aircraft), 20 hours (Last 30 days, all aircraft), 2 hours (Last 24 hours, all aircraft)
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Aircraft and Owner/Operator Information
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Aircraft Make:
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Schweizer
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Registration:
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N656RB
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|
Model/Series:
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269C
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Aircraft Category:
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Helicopter
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|
Year of Manufacture:
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1997
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Amateur Built:
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|
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Airworthiness Certificate:
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Normal
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Serial Number:
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S1744
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Landing Gear Type:
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None; Skid
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Seats:
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2
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Date/Type of Last Inspection:
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May 22, 2024 Annual
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Certified Max Gross Wt.:
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2050 lbs
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Time Since Last Inspection:
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Engines:
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1 Reciprocating
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Airframe Total Time:
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2932 Hrs as of last inspection
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Engine Manufacturer:
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Lycoming
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ELT:
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Installed
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Engine Model/Series:
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HIO-360-D1A
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Registered Owner:
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On file
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Rated Power:
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190 Horsepower
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Operator:
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On file
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Operating Certificate(s) Held:
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None
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Meteorological Information and Flight Plan
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Conditions at Accident Site:
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Visual (VMC)
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Condition of Light:
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Day
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Observation Facility, Elevation:
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KMTJ,5707 ft msl
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Distance from Accident Site:
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2 Nautical Miles
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Observation Time:
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18:53 Local
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Direction from Accident Site:
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319°
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Lowest Cloud Condition:
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Clear
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Visibility
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10 miles
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Lowest Ceiling:
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None
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Visibility (RVR):
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|
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Wind Speed/Gusts:
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3 knots / None
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Turbulence Type Forecast/Actual:
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/
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Wind Direction:
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240°
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Turbulence Severity Forecast/Actual:
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/
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Altimeter Setting:
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30.08 inches Hg
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Temperature/Dew Point:
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23°C / 0°C
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Precipitation and Obscuration:
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No Obscuration; No Precipitation
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Departure Point:
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Montrose, CO (MTJ)
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Type of Flight Plan Filed:
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None
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Destination:
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Montrose, CO (MTJ)
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Type of Clearance:
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None
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Departure Time:
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18:22 Local
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Type of Airspace:
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Class G
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Wreckage and Impact Information
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Crew Injuries:
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2 Minor
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Aircraft Damage:
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Substantial
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Passenger Injuries:
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Aircraft Fire:
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None
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Ground Injuries:
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|
Aircraft Explosion:
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None
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Total Injuries:
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2 Minor
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Latitude, Longitude:
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38.481956,-107.87284(est)
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Administrative Information
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Investigator In Charge (IIC):
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Finne, Andrew
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Additional Participating Persons:
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Behunin, Gordon; FAA-FSDO; Salt Lake City, UT
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Original Publish Date:
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September 30, 2026
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Last Revision Date:
|
|
Investigation Class:
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Class 3
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Note:
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The NTSB did not travel to the scene of this accident.
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Investigation Docket:
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https://data.ntsb.gov/Docket?ProjectID=195253
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