NTSB CAROL · Event
Event WPR23LA202
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 ↗.
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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.
- NASA NTRS 2026 · Contractor Report (CR)
Icing Physics Studies Using the 3D SIDRM Test Article: 2023 Icing Tests Analysis
In-flight icing is an important safety issue and is a factor that affects aircraft design and performance. Newer regulations are driving a need for improvements in airframe and engine icing simulation…
- arXiv 2025 · arXiv preprint
Multi-Agent Deep Reinforcement Learning for UAV-Assisted 5G Network Slicing: A Comparative Study of MAPPO, MADDPG, and MADQN
The growing demand for robust, scalable wireless networks in the 5G-and-beyond era has led to the deployment of Unmanned Aerial Vehicles (UAVs) as mobile base stations to enhance coverage in dense urb…
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Mathematical Model on the Temporal Dynamics of Aviation Competitive Pricing
This study investigates the competitive dynamics of airport pricing using U.S. airport data to validate the findings. It employs linear and nonlinear ordinary differential equation models to analyze t…
- NASA NTRS 2025 · Presentation
NASA Icing Update – March 2025
This NASA Icing Update was prepared for presentation to the SAE International AC-9C Inflight Icing Technology Committee. This update includes the following topics: planned Rotational Icing Scaling tes…
- arXiv 2024 · arXiv preprint
An energy-stable phase-field model for droplet icing simulations
A phase-field model for three-phase flows is established by combining the Navier-Stokes (NS) and the energy equations, with the Allen-Cahn (AC) and Cahn-Hilliard (CH) equations and is demonstrated ana…
- NASA NTRS 2024 · Presentation
NASA Icing Update – Oct 2024
This presentation provides a status update on select NASA icing research activities for the SAE AC-9C Icing Technical Committee Meeting on Oct 21, 2024.
Browse the full corpus — academia portal ↗