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Atlas / NTSB / WPR21LA264

NTSB CAROL · Event

Event WPR21LA264

2021-06-30 Twin Falls, Idaho, United States Airport · PVT None 1 aircraft Status: Completed

Registry · N9609H

FAA Aircraft Registry record.

Make / Model

CHRISTEN INDUSTRIES INC A-1

Year of manufacture

1990 · 31 years old at event

Engine

LYCOMING O&VO-360 SER (180 hp)

Seats / Engines

2 seats · 1 engine

Last airworthiness date

19901114

ADS-B equipped

Yes — Mode-S AD5FC1

Registrant of record

WILLIAMS MARC A

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

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.

Factual narrative

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. Source: NTSB Aviation Accident Database Retrieved: 2026-02-12

NTSB Findings

Hierarchical cause / factor breakdown from the FAA bulk avdata database. Each finding tagged C (Cause) or F (Factor).

  • Personnel issues-Task performance-Use of equip/info-Use of checklist-Pilot
  • Personnel issues-Action/decision-Action-Forgotten action/omission-Pilot
  • Aircraft-Aircraft systems-Ice/rain protection system-Intake anti-ice, deice-Not used/operated
  • Environmental issues-Conditions/weather/phenomena-Temp/humidity/pressure-Conducive to carburetor icing-Effect on equipment

Verbatim from NTSB's published report. Source file NTSB_2021_WPR21LA264.txt. Findings + structured fields enriched from FAA avall.mdb. Full investigation docket on data.ntsb.gov ↗.

Related research

What the literature says.

Academic papers and agency reports matching this event's aircraft type or causal vocabulary (icing). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.

Browse the full corpus — academia portal ↗