Beech S35 accident near Brookfield, Missouri, April 30, 2007
On April 30, 2007 at about 9:43 pm local time, a Beech S35, registered N8820M, was substantially damaged in an accident near Brookfield, Missouri. It was a personal flight under general aviation rules (Part 91). No one was hurt; 1 person was on board or involved. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
Improper maintenance by maintenance personnel by not properly torquing cylinder thru-bolts. The loose stud nuts which resulted in the separation of the cylinder and the crop and ditch were factors.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- April 30, 2007 · about 9:43 pm local time
- Place
- Brookfield, Missouri
- Type
- Accident
- Injuries
- No one was hurt; 1 person was on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech S35 · all S35s on the register
- Registration
- N8820M · no longer on the register · serial D-7331
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
he pilot reported that the engine was "operating normally" as he was flying at 6,500 feet mean sea level when the "engine blew up." He elected to execute a gear up forced landing to a corn field about two miles from the airport, but the airplane impacted a ditch during the emergency landing. The engine teardown inspection revealed a hole in the crankcase approximately 3 inches by 3 inches above the number 4 cylinder, which included the 11 and 1 o'clock deck studs. The number 4 cylinder had separated from the crankcase and the number 4 connecting rod was not attached to the number 4 crankshaft pin. The number 4 connecting rod and rod cap exhibited signatures that were consistent with an overload event that deformed and/or sheared the threads on the nuts and bolts. Cylinder number 4 deck stud nuts 6, 7, and 8 were reported missing from the engine at the accident scene, and subsequently found inside the engine cowling of the aircraft. Cylinder number 4 deck studs 6, 7, and 8 were securely attached to the engine crankcase and the threads were clean and undamaged. The 2 o'clock cylinder deck stud was fractured and missing. The remaining deck studs and thru-bolts all exhibited ductile fractures indicative of tensile overload. The other five cylinders' thru-bolt and deck stud break-away torque measurements were recorded for each thru-bolt and deck stud. The inspection revealed that numerous thru-bolts and studs had break-away torque values that did not comply with the manufacturer's limitations. The aircraft engine's logbook indicated that the engine received an annual maintenance inspection on February 16, 2005. The engine logbook entry stated, "Removed and overhauled all 6 cylinders. Installed new rings, ground valves, cleaned and gapped spark plugs." The tach time indicated 5380.5 hours at the time of the annual inspection. At the time of the accident, the tach time was 5,662.24 hours, 281.74 hours since the cylinders had been replaced.
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: 7,000 hours in all; 1,000 in this make and model; 500 in the last 90 days; 100 in the last 30 days; 7,000 as pilot in command
- Medical certificate: Class 2 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 5,662 hours
- Last inspection: annual inspection, May 1, 2006; 137 hours since
- Maximum gross weight: 3,300 lb
- Seats: 6
- Landing gear: retractable
- Engine: Continental IO-520-BA3B (piston); 0 hours total
The flight
- Departed from: M16 Raymond MS
- Destination: FOD Fort Dodge IA
- Flight plan: not recorded
Weather at the time
- Light: daylight
- Wind: from 210° at 16 knots, gusting 22
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 82°F (28°C), dew point 52°F (11°C)
- Altimeter: 29.86 inHg
- Observation at 9:55 pm from IRK, 35 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.