Saturday, December 25, 2021

Loss of Engine Power (Partial): Christen A-1 Husky, N9609H; accident occurred June 30, 2021 in Twin Falls, Idaho

Aviation Accident Final Report - National Transportation Safety Board

The National Transportation Safety Board did not travel to the scene of this accident. 

Additional Participating Entity: 
Federal Aviation Administration / Flight Standards District Office; Boise, Idaho
Location: Twin Falls, Idaho
Accident Number: WPR21LA264
Date and Time: June 30, 2021, 20:45 Local
Registration: N9609H
Aircraft Damage: Substantial
Defining Event: Loss of engine power (partial)
Injuries: 1 None
Flight Conducted Under: Part 91: General aviation - Personal


The pilot reported that he was practicing basic flight maneuvers at an altitude of about 3,500 ft agl during a short uneventful local flight. He then reduced engine power to idle and initiated a descent back to the private dirt airstrip with the intention of first performing a low pass to confirm the runway was clear, and then landing. As he flew past the runway, he applied full throttle, but the engine did not respond. He then performed a forced landing into an adjacent wheat field, where the airplane nosed over during the ground roll. The pilot stated that he had not used a checklist during the descent and forgot to apply carburetor heat. The wing lift struts, and the vertical stabilizer were substantially damaged. The pilot reported that there were no mechanical failures or malfunctions with the airplane or engine that would have precluded normal operation.

The carburetor icing chart from FAA Special Airworthiness Information Bulletin CE-09-35 “Carburetor Icing Prevention” indicated a potential for serious icing at glide power for the temperature and dew point depicted at the time of the accident.

Probable Cause and Findings

The National Transportation Safety Board determines the probable cause(s) of this accident to be:
Partial loss of engine power during a low pass, due to carburetor icing and the pilot’s failure to use carburetor heat during the landing approach.


Personnel issues Use of checklist - Pilot
Personnel issues Forgotten action/omission - Pilot
Aircraft Intake anti-ice, deice - Not used/operated
Environmental issues Conducive to carburetor icing - Effect on equipment

Factual Information

History of Flight

Maneuvering-low-alt flying Loss of engine power (partial) (Defining event)
Landing-landing roll Nose over/nose down

Pilot Information

Certificate: Private
Age: 49, Male
Airplane Rating(s): Single-engine land 
Seat Occupied: Front
Other Aircraft Rating(s): None 
Restraint Used: 5-point
Instrument Rating(s): None
Second Pilot Present:
Instructor Rating(s): None 
Toxicology Performed:
Medical Certification: Class 3 Without waivers/limitations
Last FAA Medical Exam: May 26, 2020
Occupational Pilot: No 
Last Flight Review or Equivalent: May 29, 2020
Flight Time: (Estimated) 750 hours (Total, all aircraft), 145 hours (Total, this make and model), 675 hours (Pilot In Command, all aircraft), 70 hours (Last 90 days, all aircraft), 16 hours (Last 30 days, all aircraft), 3.5 hours (Last 24 hours, all aircraft)

Aircraft and Owner/Operator Information

Registration: N9609H
Model/Series: A-1
Aircraft Category: Airplane
Year of Manufacture: 1990 
Amateur Built:
Airworthiness Certificate: Normal 
Serial Number: 1167
Landing Gear Type: Tailwheel 
Seats: 2
Date/Type of Last Inspection: November 27, 2020 Annual 
Certified Max Gross Wt.: 1800 lbs
Time Since Last Inspection: 27 Hrs
Engines: 1 Reciprocating
Airframe Total Time: 572.2 Hrs at time of accident 
Engine Manufacturer: LYCOMING
ELT: Installed, not activated 
Engine Model/Series: O-360-C1G
Registered Owner:
Rated Power: 180 Horsepower
Operating Certificate(s) Held: None

Meteorological Information and Flight Plan

Conditions at Accident Site: Visual (VMC) 
Condition of Light: Dusk
Observation Facility, Elevation: KTWF, 4151 ft msl 
Distance from Accident Site: 0 Nautical Miles
Observation Time: 20:53 Local
Direction from Accident Site: 71°
Lowest Cloud Condition: Clear
Visibility: 10 miles
Lowest Ceiling: None
Visibility (RVR):
Wind Speed/Gusts: 9 knots / 
Turbulence Type Forecast/Actual:  /
Wind Direction: 180° 
Turbulence Severity Forecast/Actual:  /
Altimeter Setting: 29.93 inches Hg 
Temperature/Dew Point: 26°C / 8°C
Precipitation and Obscuration: No Obscuration; No Precipitation
Departure Point: Hollister, ID (PVT) 
Type of Flight Plan Filed: None
Destination: Twin Falls, ID 
Type of Clearance: None
Departure Time: 20:30 Local
Type of Airspace: Class G

Wreckage and Impact Information

Crew Injuries: 1 None
Aircraft Damage: Substantial
Passenger Injuries:
Aircraft Fire: None
Ground Injuries:
Aircraft Explosion: None
Total Injuries: 1 None 
Latitude, Longitude: 42.39,-114.57 (est)


  1. PIC used carb heat on recent A-1 landings during "16 hours (Last 30 days, all aircraft), 3.5 hours (Last 24 hours, all aircraft)" ... wonder how often he "had not used a checklist" ?