Cessna T210L accident near Byron, California, August 20, 1999
On August 20, 1999 at about 2:05 am local time, a Cessna T210L, registered N5378V, was substantially damaged in an accident near Byron, California. It was a flight of an unrecorded kind under charter and air-taxi rules (Part 135). No one was hurt; 6 people were on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the operator's maintenance personnel to properly torque the cylinder and engine case through bolts during the replacement of five cylinders, which led to the spinning of the No. 2 main bearing and the resultant oil starvation induced catastrophic internal engine failure.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 20, 1999 · about 2:05 am local time
- Place
- Byron, California · map
- Type
- Accident
- Injuries
- No one was hurt; 6 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna T210L · all T210Ls on the register
- Registration
- N5378V · no longer on the register · serial 21060923
- Damage
- Substantial damage
- Flight
- Flight of an unrecorded kind · charter and air-taxi rules (Part 135)
The NTSB's narrative final · quoted from the NTSB record
The pilot said the aircraft was in level cruise at 6,500 feet msl when the engine suddenly quit without warning. The pilot switched fuel tanks and turned on the electric boost pump, which restored fuel flow on the gage, but the engine did not restart. Coincident with the loss of power, the pilot heard a 'pop' sound come from the engine compartment. The pilot selected an open field and continued to attempt a restart as he prepared for the off-airport landing. The aircraft touched down in the field and rolled some distance before the nose gear collapsed. During the teardown inspection of the engine, all cylinder bases and through bolt studs exhibited evidence of oil leakage. During removal of the cylinders, all through bolt and cylinder hold down stud nuts were loose enough to break torque with one hand using a short open-end wrench. Removal of the cylinders revealed fretted cylinder bases and pads. Separation of the case halves revealed fretting on all cylinder pads and bearing saddle-parting surfaces, with more fretting observed on the No. 2 main bearing saddle surfaces. The No. 2 main bearing was fragmented and found in the oil sump, with erosion and smearing evident to the bearing saddle. The crankshaft was fractured across the No. 3 short cheek, with heavy scoring evident to the Nos. 2 and 3 main journals. Review of the maintenance records disclosed that cylinders 1, 2, 4, 5, and 6 were replaced on March 24, 1997, 232 hours prior to the accident.
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
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instructor: airplane multi-engine; instructor: airplane single-engine; instructor: instrument airplane; instrument: airplane
- Flight time: 8,205 hours in all; 668 in this make and model; 148 in the last 90 days; 55 in the last 30 days; 7,900 as pilot in command; 4,530 on instruments
- Medical certificate: Class 2 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 4,070 hours
- Last inspection: 100-hour inspection, August 11, 1999; 10 hours since
- Maximum gross weight: 3,800 lb
- Seats: 6
- Landing gear: retractable
- Engine: Continental TSIO-520-HCR (piston); 0 hours total
The flight
- Departed from: Q68 Groveland CA at 1:30 am
- Destination: CCR Concord CA
- Runway 0
Weather at the time
- Light: daylight
- Wind: from 300° at 10 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 90°F (32°C), dew point 0°F (-18°C)
- Altimeter: 29.00 inHg
- Observation at 2:22 am from SCK, 9 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 5 |
Documents from the investigation the NTSB's docket: the evidence folder behind the report
The docket, the folder of records gathered during an investigation (maintenance records, photographs, witness statements, examinations), has not been read from the NTSB for this case yet; the list appears here once it has. Open the docket at the NTSB.
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.