Beech V35 incident near Mount Vernon, Ohio, August 16, 2015
On August 16, 2015 at about 11:55 pm local time, a 1965 Beech V35, registered N2059W, was involved in an incident during enroute (cruise) near Mount Vernon, Ohio (Knox County airport). It was a personal flight under general aviation rules (Part 91). No one was hurt; 2 people were on board or involved. The weather was visual conditions (good weather).
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The NTSB's probable cause their words, unchanged
The loosening of the flyweight due to the installation of an improperly hardened flyweight carrier, which resulted in the overspeed of the propeller and engine and the subsequent in-flight separation of the propeller.
Source: NTSB aviation accident database, copy made October 4, 2026. Docket and reports at the NTSB.
What the record shows
- Date
- August 16, 2015 · about 11:55 pm local time
- Place
- Mount Vernon, Ohio · Knox County · map
- Type
- Incident
- Injuries
- No one was hurt; 2 people were on board or involved.
- Weather
- visual conditions (good weather)
- Aircraft
- Beech V35, built 1965 · all V35s on the register
- Registration
- N2059W · registry record · serial D-7993
- Damage
- Not recorded
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
The commercial pilot was conducting a personal cross-country flight. The pilot reported that, during cruise flight, he heard a sudden high-pitched whine emanating from the engine and saw that the tachometer was reading about 3,500 rpm. He was unable to bring the engine rpm within limits and diverted the airplane to the nearest airport. During the approach, he heard a "pop," and oil covered the windscreen. After landing, he found that the propeller was missing from the airplane. A postaccident examination of the engine found metal particulates in the propeller governor. An examination of the governor revealed that a flyweight was not secured and that the flyweight carrier did not meet the factory hardness specifications. The flyweight's retaining pin hole was excessively worn, which had allowed the pin to back out and the flyweight to become loose and resulted in the overspeed of the propeller and engine and the subsequent in-flight separation of the propeller. A review of factory records did not find any similar incidents or a history of a batch of materials not meeting factory specifications. A review of the maintenance records revealed that an overhauled propeller governor had been installed on the airplane about 16 years before the accident; however, it could not be determined if the improper flyweight carrier was installed in the propeller governor during the overhaul or at some time after the overhaul.
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
- Aircraft maintenance event during prior to flight
- Powerplant sys/comp malf/fail during enroute (cruise) defining event
- Part(s) separation from AC during approach
The NTSB's findings
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Incorrect service/maintenance
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Malfunction
- cause Personnel issues › Task performance › Maintenance › Installation › Other/unknown
- cause Aircraft › Aircraft propeller/rotor › Propeller system › Propeller governor › Failure
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; instrument: airplane
- Flight time: 2,475 hours in all; 630 in this make and model; 14 in the last 90 days; 14 in the last 30 days; 2,350 as pilot in command
- Last flight review: July 26, 2015
- Medical certificate: Class 3 (with waivers/limitations)
- Seat: left
- Injury: no injuries
The aircraft
- Airframe total time: 5,394 hours
- Last inspection: annual inspection, July 19, 2015; 14 hours since
- Maximum gross weight: 3,400 lb
- Seats: 4
- Landing gear: retractable
- Engine: Continental IO-520-BA (piston); 2,300 hours total
The flight
- Departed from: RUQ Salisbury NC at 10:00 pm
- Destination: ARB Ann Arbor MI
- Flight plan: IFR
- Runway 28, 5,498 ft by 100 ft
Weather at the time
- Light: dusk
- Visibility: 10 statute miles
- Sky: clear
- Temperature: 79°F (26°C), dew point 66°F (19°C)
- Altimeter: 30.12 inHg
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flig | 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 CEN15IA365.