Cessna 340A accident near Hayward, California, October 2, 2023
On October 2, 2023 at about 7:50 pm local time, a 1976 Cessna 340A, registered N121CB, was substantially damaged in an accident during taxi near Hayward, California (Hayward Executive Airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
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.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- October 2, 2023 · about 7:50 pm local time
- Place
- Hayward, California · Hayward Executive Airport · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 340A, built 1976 · all 340As on the register
- Registration
- N121CB · registry record · serial 340A0087
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
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.
The complete narrative as the NTSB published it. The NTSB's docket holds the report as a PDF and any photographs, statements and other documents from the investigation.
The factual record from the NTSB's investigation tables, in plain English
What happened, in order
- Medical event during taxi defining event
- Loss of control on ground during taxi
- Collision with terrain or object (not controlled flight into terrain) during taxi
The NTSB's findings
- 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
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane; rotorcraft: glider
- Flight time: 2,135 hours in all; 304 in this make and model; 29 in the last 90 days; 3.8 in the last 30 days
- Last flight review: March 15, 2022
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
Passenger
- Seat: rgt
- Injury: no injuries
The aircraft
- Last inspection: annual inspection, September 22, 2023; 6 hours since
- Maximum gross weight: 6,430 lb
- Seats: 6
- Landing gear: retractable
- Engine 1: Continental TSIO-520 (piston); 600 hours total
- Engine 2: Continental TSIO-520 (piston); 300 hours total
The flight
- Destination: KMRY Monterey CA
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 270° at 7 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 70°F (21°C), dew point 52°F (11°C)
- Altimeter: 30.04 inHg
- Observation at 12:54 pm from KHWD
Weather report (METAR): KHWD 021954Z 27007KT 10SM CLR 21/11 A3004 RMK AO2 SLP180 T02060111
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
7 documents, released by the NTSB on September 30, 2025. View them here, or download them; the NTSB redacts some personal details before release, and this site shows the NTSB's own titles rather than its file names.
| # | Document | What it is | |
|---|---|---|---|
| 1 | Pilot/operator Aircraft Accident Report, NTSB Form 6120.1 | PDF, 9 pages | View Download |
| 2 | Hayward Executive Airport-accident Report | PDF, 2 pages | View Download |
| 3 | Vehicle Dash Cam View-video | video | View Download |
| 4 | Vehicle Rear View-video | video | View Download |
| 5 | Photo Array-courtesy of the Hayward Executive Airport | PDF, 5 pages | View Download |
| 6 | Email-pilot Condition | PDF, 1 page | View Download |
| 7 | Medical Factual | PDF, 6 pages | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Everything on this page comes from the NTSB's public records. The narrative, probable cause and findings are the NTSB's own words; the coded tables behind the report are written out in plain English, with pilots' ages, home towns and medical details left out. The documents and photographs are the NTSB's docket, shown as the NTSB released them. This site's own text never names anyone involved. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.