Beech C23 accident near Duncan, Oklahoma, September 28, 2008
On September 28, 2008 at about 8:25 pm local time, a Beech C23, registered N6714E, was substantially damaged in an accident during maneuvering near Duncan, Oklahoma. It was a personal flight under general aviation rules (Part 91). 2 people had minor injuries. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
A total loss of engine power due to the fatigue failure of the engine crankshaft. Contributing to the accident were the improper maintenance to the engine crankshaft, improper reassembly of the engine, and failure to follow the engine manufacturer's overhaul manual.
Source: NTSB aviation accident database, copy made October 5, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- September 28, 2008 · about 8:25 pm local time
- Place
- Duncan, Oklahoma · map
- Type
- Accident
- Injuries
- 2 people had minor injuries.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech C23 · all C23s on the register
- Registration
- N6714E · no longer on the register · serial M-2200
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During the local flight, the airplane's engine began to violently shake and the pilot elected to shut down the engine and perform an emergency landing to a field. The airplane impacted a fence and terrain, which resulted in a bent firewall and left wing. A review of the maintenance records showed that, approximately 23 hours prior, the engine had experienced a loss of engine oil due to faulty maintenance during an annual inspection. The engine underwent maintenance and the airplane was returned to service. Examination and disassembly of the engine revealed that the crankshaft had fractured into 3 sections and that improper maintenance had been performed on several engine components. Metallurgical examination of the crankshaft revealed that the crankshaft had been improperly reworked which resulted in fatigue and crankshaft failure. The crankshaft rework and engine reassembly did not follow the manufacturer's overhaul manual.
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
What happened, in order
- Powerplant sys/comp malf/fail during maneuvering defining event
- Loss of engine power (total) during emergency descent
The NTSB's findings
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Failure
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Fatigue/wear/corrosion
- factor Personnel issues › Task performance › Maintenance › Repair › Maintenance personnel
- factor Aircraft › Aircraft power plant › Engine (reciprocating) › Recip engine power section › Incorrect service/maintenance
- factor Personnel issues › Task performance › Use of equip/info › Use of manual › Maintenance personnel
Pilot
- Certificate: private
- Ratings: single-engine land
- Flight time: 113 hours in all; 27 in this make and model; 11 in the last 90 days; 3 in the last 30 days; 52 as pilot in command
- Last flight review: June 4, 2007
- Medical certificate: Class 3 (without waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 1,688 hours
- Last inspection: annual inspection, December 20, 2007; 26 hours since
- Maximum gross weight: 2,450 lb
- Seats: 4
- Landing gear: fixed
- Engine: Lycoming O-360-A4K (piston); 0 hours total
The flight
- Departed from: DUC Duncan OK at 8:00 pm
- Destination: DUC Duncan OK
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 100° at 4 knots
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 81°F (27°C), dew point 0°F (-18°C)
- Altimeter: 30.12 inHg
- Observation at 8:00 pm from DUC
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.
Other NTSB records under N6714E the same tail number, which may have belonged to a different aircraft at the time
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.