Beech A36TC accident near Southbury, Connecticut, April 20, 2005
On April 20, 2005 at about 8:03 pm local time, a Beech A36TC, registered N3810X, was substantially damaged in an accident near Southbury, Connecticut (Waterbury-Oxford airport). It was a business flight under general aviation rules (Part 91). 1 person had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The failure of the counter weight aft snap ring to hold the associated plate and pin in place, which resulted in a total loss of engine power.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 20, 2005 · about 8:03 pm local time
- Place
- Southbury, Connecticut · Waterbury-Oxford · map
- Type
- Accident
- Injuries
- 1 person had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech A36TC · all A36TCs on the register
- Registration
- N3810X · no longer on the register · serial EA186
- Damage
- Substantial damage
- Flight
- Business flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During taxi, runup, and takeoff, the pilot did not notice any anomalies with the engine, and the flight progressed without incident until about 90 miles short of the intended destination when the engine started to run rough for a few seconds before it stopped producing power. The windscreen became covered with oil, and the pilot executed an off airport forced landing, substantially damaging the airplane. External examination of the engine revealed three holes in the top of the engine case, and a crankshaft counter weight pin resting on top of the engine. Internal examination of the engine revealed heavy mechanical damage on the No. 5 counter weight, and the engine case in the vicinity of the No. 3 and No. 4 cylinders. Examination of the No. 5 counter weight assembly revealed that one of the two aft snap rings, plates, and pins were missing. The pin was located on top of the engine during the external examination, but neither the snap ring nor plate could be located. The fact that the engine was operated for approximately 16 hours since overhaul, along with the witness mark on the surface of the counter weight, suggested that the snap ring, plate, and pin were installed; however, it could not be determined if the snap ring was properly seated. A review of engine overhaul records revealed that on February 5, 2005, the counterweights, along with the pins, plates, and snap rings were installed on the crankshaft.
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: private
- Ratings: single-engine land; instrument: airplane
- Flight time: 1,783 hours in all; 1,560 in this make and model; 22 in the last 90 days; 16 in the last 30 days; 1,783 as pilot in command
- Last flight review: June 1, 2004
- Medical certificate: Class 3
- Seat: left
- Injury: minor injuries
The aircraft
- Airframe total time: 3,445 hours
- Last inspection: annual inspection, March 1, 2005; 16 hours since
- Maximum gross weight: 3,650 lb
- Seats: 6
- Landing gear: retractable
- Engine: Continental TSIO-520-K1B (piston); 0 hours total
The flight
- Departed from: CGF Cleveland OH at 5:30 pm
- Destination: PVD Providence RI
- Flight plan: IFR
Weather at the time
- Light: daylight
- Wind: from 230° at 9 knots, gusting 17
- Visibility: 10 statute miles
- Sky: a few clouds at 4,500 ft
- Temperature: 81°F (27°C), dew point 43°F (6°C)
- Altimeter: 29.70 inHg
- Observation at 8:15 pm from OXC, 5 miles away
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Crew | 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.