Cessna 150F accident near Middlesboro, Kentucky, March 13, 2008
On March 13, 2008 at about 7:20 pm local time, a Cessna 150F, registered N6651F, was substantially damaged in an accident during enroute (cruise) near Middlesboro, Kentucky (Middlesboro-Bell County airport). It was a personal flight under general aviation rules (Part 91). 1 person was seriously injured. The weather was visual conditions (good weather).
The NTSB's probable cause their words, unchanged
The mechanic's improper maintenance installation of the No. 1 cylinder rocker arms which led to oil starvation and a 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
- March 13, 2008 · about 7:20 pm local time
- Place
- Middlesboro, Kentucky · Middlesboro-Bell County · map
- Type
- Accident
- Injuries
- 1 person was seriously injured.
- Weather
- visual conditions (good weather)
- Aircraft
- Cessna 150F · all 150Fs on the register
- Registration
- N6651F · no longer on the register · serial 15063251
- Damage
- Substantial damage
- Flight
- Personal flight · general aviation rules (Part 91)
The NTSB's narrative final · quoted from the NTSB record
During a period of 6 months, a major engine overhaul and annual inspection was being performed on the pilot's airplane. The work was being performed by the pilot's friend, who was an airframe and powerplant mechanic with an inspector authorization. The accident flight was the first flight after the work was completed. About 10 minutes after departure, the engine began vibrating and lost all power during cruise flight. The major overhaul had included the installation of new cylinders. Proper installation of the new cylinders required that the exhaust valve rocker arms have a small orifice to allow oil to pass and lubricate the valves. The intake valve rocker arms did not have an orifice. Examination of the accident engine revealed that the No. 1 cylinder intake valve was stuck open, and exhibited features consistent with oil starvation. Further examination revealed that the No. 1 cylinder had an intake rocker arm (no orifices) on both the intake and exhaust valves. The No. 3 cylinder had an exhaust valve rocker arm (with orifice) on both the intake and exhaust valves. Review of a make and model engine overhaul manual revealed a caution, noting that the exhaust valve rocker arms have an orifice. Further examination of the cylinder did not reveal any additional mechanical anomalies.
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
- Loss of engine power (total) during enroute (cruise) defining event
- Off-field or emergency landing during emergency descent
- Controlled flight into terrain or object (CFIT) during approach
The NTSB's findings
- cause Personnel issues › Task performance › Maintenance › Installation › Maintenance personnel
- cause Aircraft › Aircraft power plant › Engine (reciprocating) › Recip eng cyl section › Incorrect service/maintenance
Pilot
- Certificate: commercial pilot
- Ratings: multi-engine land; single-engine land; single-engine sea; instrument: airplane
- Flight time: 742 hours in all; 72 in this make and model; 5 in the last 90 days; 1 in the last 30 days; 742 as pilot in command
- Last flight review: October 1, 2007
- Medical certificate: Class 3
- Seat: left
- Injury: serious injuries
The aircraft
- Airframe total time: 4,029 hours
- Last inspection: annual inspection, March 1, 2008
- Maximum gross weight: 1,600 lb
- Seats: 2
- Landing gear: fixed
- Engine: Continental O-200 (piston); 0 hours total
The flight
- Departed from: 1A6 Middlesboro KY at 7:10 pm
- Destination: PBX Pikeville KY
- Flight plan: none
Weather at the time
- Light: daylight
- Wind: from 180° at 15 knots, gusting 19
- Visibility: 10 statute miles
- Sky: scat at 9,000 ft
- Temperature: 72°F (22°C), dew point 39°F (4°C)
- Altimeter: 29.86 inHg
- Observation at 7:15 pm from 1A6
Injuries
| Fatal | Serious | Minor | None | |
|---|---|---|---|---|
| Flight 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.