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Atlas / NTSB / WPR23LA202

NTSB CAROL · Event

Event WPR23LA202

2023-05-25 Napa, California, United States Airport · APC Minor 1 aircraft Status: Completed

Registry · N201MM

FAA Aircraft Registry record.

Make / Model

MOONEY M-18C 55

Year of manufacture

1955 · 68 years old at event

Engine

CONT MOTOR A&C65 SERIES (65 hp)

Seats / Engines

1 seats · 1 engine

Last airworthiness date

19570619

ADS-B equipped

Yes — Mode-S A196D9

Registrant of record

HARMS KAREN

Source: FAA Aircraft Registry (releasable master file).

Aircraft involved

Probable cause & findings

The pilot’s failure to use carburetor heat, which resulted in a loss of engine power due to carburetor icing and a subsequent impact with terrain during a forced landing.

Factual narrative

On May 25, 2023, about 1846 Pacific daylight time, a Mooney M-18C, N201MM, was substantially damaged when it was involved in an accident near Napa, California. The sole occupant on board sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he departed Ed Carlson Memorial Field - South Lewis County Airport (KTDO), Toledo, Washington, for a multi-leg cross-country flight destined for Napa County Airport (KAPC). During the approach to land at KAPC, about 8 miles north of the airport and 3,000 ft agl, the engine lost all power. The pilot cycled the throttle control to full, but the engine did not restart and the propeller continued to windmill. He then declared an emergency and initiated a forced landing onto an open field about 5 miles north of runway 19R. During the landing roll on unimproved terrain, the left wing struck a large rock and came to rest nose down. Subsequently, the left wing sustained substantial damage. Recovery of the airplane revealed that the airplane had about 13 gallons of fuel in its main tank and 7 gallons in its auxiliary tank. A postaccident examination of the airplane and engine did not reveal any preimpact mechanical anomalies. The fuel system was traced from each wing tank to the carburetor at the engine through the fuel selector, which rotated normally and was unobstructed. The fuel lines that had not been damaged from impact or removed to transport the airplane were secure. Mechanical continuity of the engine was established throughout the rotating group, valvetrain, and accessory section as the crankshaft was manually rotated at the propeller by hand. Thumb compression was achieved at all four cylinders and the valves displayed normal lift when the crankshaft was rotated. Examination of the cylinders’ combustion chamber interior components using a lighted borescope revealed normal piston face and valve signatures, and no indications of catastrophic engine failure. At 1754, the weather reported at KAPC, about 6 miles south of the accident site, included a temperature of 63°F and a dew point 52°F; the calculated relative humidity was about 67%. Review of the icing probability chart contained within FAA Special Airworthiness Information Bulletin CE-09-35 revealed that the atmospheric conditions at the time of the accident were "conducive to serious icing at glide [idle] power." The pilot added that he did not use carburetor heat during the descent and approach into KAPC and that he should have used a prelanding checklist. The pilot was on an approach to the airport about 3,000 ft above ground level (agl) when the engine lost all power. The pilot cycled the throttle control to full, but the engine did not restart and the propeller continued to windmill. He then declared an emergency and initiated a forced landing onto an open field about 5 miles north of the runway. During the landing roll on unimproved terrain, the left wing struck a large rock and came to rest nose down. Subsequently, the left wing sustained substantial damage. During recovery of the aircraft, about 20 gallons of fuel remained in its tanks; a postaccident examination of the airplane and engine did not reveal any preimpact mechanical anomalies. The temperature at the airport, which was about 6 miles south of the accident site, was 63°F and the dew point was 52°F; the relative humidity was about 67%. A review of the icing probability chart contained within FAA Special Airworthiness Information Bulletin CE-09-35 revealed that the atmospheric conditions at the time of the accident were "conducive to serious icing at glide [idle] power." The pilot added that he did not use carburetor heat during the descent and approach and that he should have used a pre-landing checklist. 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-Action/decision-Action-Lack of action-Pilot
  • Personnel issues-Task performance-Use of equip/info-Use of checklist-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_2023_WPR23LA202.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, engine failure). 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 ↗