Aeronca 11AC accident near Winchester, California, July 27, 2024
On July 27, 2024 at about 6:57 pm local time, a 1946 Aeronca 11AC, registered N86270, was substantially damaged in an accident during enroute (cruise) near Winchester, California. 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
A total loss of engine power due to a fatigue fracture of the crankshaft.
Source: NTSB aviation accident database, copy made November 2, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- July 27, 2024 · about 6:57 pm local time · cases in 2024
- Place
- Winchester, California · map
- Type
- Accident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Aeronca 11AC, built 1946 · all 11ACs on the register
- Registration
- N86270 · registry record · serial 11AC-75
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot of the tailwheel-equipped airplane reported that, while nearing his intended destination on a cross-country flight, the engine lost partial power followed by a vibration and grinding sound. The pilot attempted to restore engine power by troubleshooting; however, the engine subsequently lost total power and he initiated a forced landing to an open field. When the main wheels touched the soft terrain, the airplane nosed over, which resulted in substantial damage to the left wing. Postaccident examination of the engine revealed metallic debris in the oil sump. The engine was disassembled by the previous owner, and the crankshaft was found fractured at the forward area of the No. 1 cylinder connecting rod journal. The entire fracture surface exhibited beach marks, consistent with high cycle fatigue over multiple duty cycles. The reason for the fatigue fracture was not determined. The engine was last overhauled about 60 years before the accident and had accumulated about 1,569 hours of operation since overhaul. The supplied logbook excerpts consisted of 2 entries, and as such, it could not be determined what engine work was accomplished since the overhaul was performed. The engine manufacturer’s recommended time between overhauls is 12 years or 1,800 hours since overhaul.
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
- Off-field or emergency landing during landing
- Nose over/nose down during landing
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
The NTSB's findings
- Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Fatigue/wear/corrosion other cases naming the engine
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 249 hours in all; 69 in this make and model; 25 in the last 90 days; 13 in the last 30 days; 166 as pilot in command
- Last flight review: September 23, 2022
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Seats: 2
- Landing gear: fixed
- Engine: Cont Motor C85-12 (piston); 0 hours total
The flight
- Departed from: SDM San Diego CA
- Destination: HMT San Jacinto CA
Weather at the time
- Light: daylight
- Wind: from 200° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 95°F (35°C), dew point 50°F (10°C)
- Altimeter: 29.90 inHg
- Observation at 12:55 pm from KHMT, 4 miles away
Weather report (METAR): METAR KHMT 271955Z AUTO 20011KT 10SM CLR 35/10 A2990 RMK AO2=
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight crew | 1 | |||
| Passengers | 1 |
Photographs from the investigation 1 picture from the NTSB's docket, as the NTSB released them
The NTSB's photographs with the NTSB's captions, at screen size. Open a picture to see it full size or to report one that should not be shown.
Documents from the investigation the NTSB's docket: the evidence folder behind the report
6 documents, released by the NTSB on May 27, 2026. 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, 11 pages | View Download |
| 2 | Mor - Pilot | PDF, 2 pages | View Download |
| 3 | Logbooks | PDF, 3 pages | View Download |
| 4 | Materials Laboratory Factual Report 25-083 | PDF, 5 pages | View Download |
| 5 | Continental Motors M-0 Manual, Chapter 6, Time Between Overhaul Requirements | PDF, 1 page | View Download |
| 6 | Photo Array | PDF, 2 pages · our copy | View Download |
The same docket at the NTSB · documents without a copy here are fetched from the NTSB when you open them.
Connections how this case links to the rest of the register
- N86270 on the register today · the tail number may have moved to another aircraft since
- Aeronca 11 Chief 741 registered today · the model family and its accident history
- Aeronca 3,953 aircraft on the register
- Engine: Cont Motor C85-12 82 aircraft carry this series today · as the NTSB recorded it
- Brown Field Municipal · departed from
- Hemet-Ryan Airport · bound for
- Accidents and incidents in California 9,080 since 1982 · 1,096 in the last ten years
- California 28,158 aircraft registered
The whole map of how records connect · these connections as data: /graph/accident/WPR24LA261.json.
The bigger picture in Aviation Analytics: accidents over time since 1982, by model, by phase of flight and conditions, by place and on the map.
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 does not name anyone involved, its policy at this time. A preliminary report can change; the final report usually follows one to two years later, and the page is refreshed when it does.