Beech 35-C33A accident near Paso Robles, California, April 20, 2005
On April 20, 2005 at about 1:23 am local time, a Beech 35-C33A, registered N299X, was substantially damaged in an accident near Paso Robles, California (Paso Robles airport). It was a personal flight under general aviation rules (Part 91). 2 people were seriously injured. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
the separation of the number 4 engine cylinder due to improperly torqued cylinder hold down nuts. A finding in this accident was the lack of a shoulder restraint system in the airplane, which contributed to the occupants' injuries.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 20, 2005 · about 1:23 am local time
- Place
- Paso Robles, California · Paso Robles · map
- Type
- Accident
- Injuries
- 2 people were seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech 35-C33A · all 35-C33As on the register
- Registration
- N299X · registry record · serial CE-37
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The number 4 cylinder and piston separated from the engine during cruise flight and the airplane collided with vine trellises and terrain during an emergency landing in a vineyard. While in flight at 8,500 feet mean sea level, the pilot heard a loud noise and the engine started running rough. He started to divert to a nearby airport when there was another loud bang from the engine compartment; engine rpm dropped dramatically, and the cockpit started to fill with white smoke. He was being vectored to a nearby airport when the cowling popped open and remained open, substantially increasing the airplane's rate of descent. The pilot set up to land in a vineyard by lowering the airplane's landing gear and approaching the field at 45 degrees to the vineyard rows. He started the landing at 75 knots when the left main landing gear snagged a grape vine row pole and wires. The plane veered to the left, and stopped almost immediately. He recalled that his head hit the dashboard during the landing and his passenger in the right seat was unconscious after the landing. Shoulder harnesses or straps were not installed on this airplane, only lap belts. The calculated landing decelerating force was about 19.5 g's, which resulted in both occupants receiving serious head injuries. Post accident examination of the engine revealed that the number 4 cylinder had departed the engine along with the piston. The engine case halves were fractured directly above the number 4 cylinder location. The two upper right cylinder hold down studs were present and appeared undamaged, while the bottom studs were sheared across their diameter above the engine case, and left-hand side studs were sheared across their diameters at the engine case surface. The number 4 cylinder base pad surface of the crankcase exhibited fretting at the 3 and 9 o'clock positions. This condition is consistent with the right-hand and bottom cylinder hold down nuts backing off during engine operation allowing the number 4 cylinder to move in rhythm with the piston until the remaining cylinder studs on the left side failed under the cyclic load. The backing off of the cylinder hold down nuts would not normally occur if the nuts had been properly torqued when installed. The number 2, 4, 5, and 6 cylinders had been removed and replaced or reinstalled 186.2 hours prior to the accident. The under-torqued cylinder hold down nuts were not detected during the 100-hour inspection that was performed 88.1 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: flight instructor, commercial pilot, foreign licence
- Ratings: single-engine land; instructor: airplane single-engine
- Flight time: 550 hours in all; 12 in this make and model; 490 as pilot in command; 20 on instruments
- Last flight review: August 1, 2004
- Medical certificate: Class 1
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 6,106.8 hours
- Last inspection: annual inspection, June 1, 2004; 162.5 hours since
- Maximum gross weight: 3,300 lb
- Seats: 4
- Landing gear: retractable
- Engine: Teledyne Continental IO-520 (piston); 0 hours total
The flight
- Departed from: KVNY Van Nuys CA
- Destination: KRHV San Jose CA
- Flight plan: IFR
Weather at the time
- Light: daylight
- Wind: from 200° at 11 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 59°F (15°C), dew point 45°F (7°C)
- Altimeter: 29.92 inHg
- Observation at 1:53 am from KPRB, 2 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 1 | |||
| Passengers | 1 |
About this page
Everything above comes from the NTSB's public accident database: the narrative, probable cause and findings are the NTSB's own words, and the coded tables behind its report (pilot, aircraft, flight, weather, injuries, sequence of events) are written out in plain English. Pilots' ages, home towns and medical details are left out on purpose. The docket at the NTSB holds the report as a PDF and the investigation's photographs and documents. This site never names pilots, passengers or anyone else involved. A preliminary report describes what is known soon after the event and can change; the final report, with the probable cause, usually follows one to two years later and this page is refreshed when it does. Case number LAX05LA140.