Beech J35 accident near Marysville, California, August 17, 1999
On August 17, 1999 at about 6:31 pm local time, a Beech J35, registered N4932B, was destroyed in an accident near Marysville, California (Yuba County airport). It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A loss of engine power due to improperly torque cylinder base nuts by maintenance personnel during a top overhaul.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 17, 1999 · about 6:31 pm local time
- Place
- Marysville, California · Yuba County · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech J35 · all J35s on the register
- Registration
- N4932B · no longer on the register · serial D-5541
- Damage
- Destroyed
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The pilot radioed that the aircraft's engine was failing and he was altering his course to land at the nearest airport. While on left base leg for landing, the cowling flew open, oil filled the windshield, and the engine ceased delivering power. The aircraft impacted a tree and came to rest in a city park. At the scene, the No. 6 engine cylinder was separated from the crankcase and engine components associated with that cylinder were found over a 40-foot radius around the aircraft. The engine crankcase where the No. 6 cylinder attached was broken away at the 12 o'clock position; the upper forward, upper rear, and lower rear mounting studs were broken; and the lower forward stud and the two lower center studs were present. The skirt of the No. 6 cylinder exhibited a pattern of longitudinal striations where it mated into the crankcase opening. At the lower left of the cylinder mount location was a small ledge of material, which approximated the shape of the circumference of the cylinder base flange. Opposite this location, on the upper right of the cylinder mounting location, was a brightly polished wear area. The engine received a top overhaul 7 months, 41.8 hours prior to the accident. Breakaway torque was measured on the remaining cylinder base nuts and found to range between 25 and 40 foot-pounds; the specification torque values are between 40.8 and 42.5.
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; instrument: airplane
- Flight time: 1,596 hours in all; 25 in the last 90 days; 8 in the last 30 days; 1,427 as pilot in command
- Medical certificate: Class 3 (valid medical--w/ waivers/lim.)
- Seat: left
The aircraft
- Airframe total time: 5,202 hours
- Last inspection: annual inspection, January 29, 1999; 42 hours since
- Maximum gross weight: 2,900 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental IO-470-C (piston); 0 hours total
The flight
- Departed from: San Rafael CA at 5:45 pm
- Destination: U35 Caldwell ID
- Flight plan: none
- Runway 14, 6,006 ft by 150 ft
- A second pilot was aboard
Weather at the time
- Light: daylight
- Wind: from 240° at 9 knots
- Visibility: 35 statute miles
- Sky: scat at 25,000 ft
- Temperature: 88°F (31°C), dew point 55°F (13°C)
- Altimeter: 30.00 inHg
- Observation at 6:50 pm from MYV, 1 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
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.