NTSB CAROL · Event
Event WPR24LA003
Registry · N121CB
FAA Aircraft Registry record.
Make / Model
CESSNA 340A
Year of manufacture
1976 · 47 years old at event
Engine
CONT MOTOR TSIO-520 SER (300 hp)
Seats / Engines
6 seats · 2 engines
Last airworthiness date
19760802
ADS-B equipped
Yes — Mode-S A0579D
Registrant of record
CLARK ANDREW R
Source: FAA Aircraft Registry (releasable master file).
Aircraft involved
Probable cause & findings
The pilot’s sudden incapacitation from effects of a previously undiagnosed underlying heart disease, which resulted in his loss of control of the airplane and subsequent impact with terrain.
Factual narrative
On October 2, 2023, about 1250 Pacific daylight time, a Cessna 340A airplane, N121CB, was substantially damaged when it was involved in an accident near Hayward, California. The pilot and passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that the airplane was parked next to his hangar and that he had just started the engines for the upcoming flight. He turned on the avionics and shortly thereafter lost consciousness. The airplane started moving onto taxiway A and into the runway safety area next to the runway. The nose landing gear collapsed and the engines came to a stop. The pilot woke up at the accident site and shut off the fuel and avionics. The pilot’s wife, who was the passenger, attempted to wake him up while the airplane was in motion. On arrival to the emergency department, the pilot was awake and alert with no recollection of the event. He denied any prior chest pain or dizziness. He did report that in February 2023, about 8 months before the accident, he had been evaluated for an acute illness and had undergone an ECG that had been abnormal. He had been referred for a cardiac stress test by his primary care physician but had not completed it by the time the accident occurred. The pilot, who held a Class 3 medical certification from the FAA without waivers, was evaluated by a cardiology provider in the emergency department, who reviewed the ECG and noted findings consistent with a possible previous heart attack but saw no definitive changes indicating a current heart attack. The cardiology provider documented that the pilot’s elevated troponin was likely the result of a recent arrhythmia, as the pilot did not have a history of chest pain. The cardiology provider stated that it seemed likely that the syncopal episode was the result of some kind of acute arrhythmia. The pilot was admitted to the hospital for monitoring overnight and discharged with follow-up appointments the next day. On follow-up with the cardiologist, the pilot underwent a cardiology evaluation that included a Holter monitor, cardiac MRI, stress test, and cardiac catheterization. The catheterization found significant coronary artery narrowing that was treated with percutaneous transcatheter angioplasty and placement of a coronary artery stent. The pilot had just removed the airplane from his hangar and started both engines. While setting up the avionics, the pilot was suddenly incapacitated, and the airplane began to move across a taxiway. The passenger attempted to wake the pilot, but the airplane continued across a taxiway intersection and into the runway safety area before it collided with a swale. The nose landing gear collapsed and both wings sustained substantial damage. Postaccident medical examination of the pilot attributed the loss of consciousness to an episode of abnormal heartbeat due to a previously undiagnosed underlying heart disease. Thus, the pilot’s sudden incapacitation from effects of previously undiagnosed heart disease likely caused the accident. The pilot reported that there were no preaccident mechanical malfunctions or failures with the airplane that would have precluded normal operation. 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-Physical-Impairment/incapacitation-Other loss of consciousness-Pilot
- — Environmental issues-Physical environment-Terrain-Sloped/uneven terrain-Contributed to outcome
- — Personnel issues-Physical-Health/Fitness-Predisposing condition-Pilot
Verbatim from NTSB's published report. Source file
NTSB_2023_WPR24LA003.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 (loss of control). Sourced from NASA NTRS, NTSB Safety Studies, FAA CAMI, AOPA Air Safety Institute, Embry-Riddle Scholarly Commons, arXiv, and the Semantic Scholar academic graph.
- Embry-Riddle Scholarly Commons 2025 · Journal article (JAAER)
A Scoping Review of Aviation Loss of Control Inflight Research
Loss of control – inflight (LOC-I) contributes to aircraft accidents at unacceptably high rates. Significant industry efforts and research have aimed to improve LOC-I prevention, detection, and recove…
- SKYbrary (Eurocontrol) 2024 · SKYbrary article
Loss of Control In-Flight (LOC-I) — SKYbrary Knowledge Base
SKYbrary comprehensive knowledge-base entry on Loss of Control In-Flight — definitions, contributing factors, accident case studies (Air France 447, Colgan 3407), and prevention strategies.
- NTSB Aircraft Accident Reports 2022 · Accident report
Loss of Control on Takeoff in Icing Conditions — Citation 560XL
Cessna Citation 560XL fatal takeoff icing accident, March 2018. Investigation of a Citation 560XL loss-of-control takeoff accident in icing conditions.
- Semantic Scholar 2021 · Article (Aviation)
ANALYSIS OF GENERAL AVIATION FIXED-WING AIRCRAFT ACCIDENTS INVOLVING INFLIGHT LOSS OF CONTROL USING A STATE-BASED APPROACH
Inflight loss of control (LOC-I) is a significant cause of General Aviation (GA) fixed-wing aircraft accidents. The United States National Transportation Safety Board’s database provides a rich source…
- NASA NTRS 2021 · Presentation
Use of Design of Experiments in Determining Neural Network Architectures for Loss of Control Detection
Abstract—We describe empirical methods for selecting a neural network architecture to implement belief state inference on generic commercial transport aircraft.
- NASA NTRS 2021 · Conference Paper
Use of Design of Experiments in Determining Neural Network Architectures for Loss of Control Detection
We describe empirical methods for selecting a neural network architecture to implement belief state inference on generic commercial transport aircraft.
Browse the full corpus — academia portal ↗