Cessna 150F N6651F

Summary

On 13 March 2008 at about 19:20 local time, a Cessna 150F registered N6651F was involved in an accident near Middlesboro, Kentucky, United States. One person was on board and one was seriously injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

13 March 2008 at 19:20

Classification

Accident

Location

Middlesboro, Kentucky, United States

Nearest airport

Middlesboro-Bell County (1A6)

Coordinates

36.6106, -83.7372

Aircraft

Cessna 150F

Registration

N6651F

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Middlesboro → Pikeville

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

NYC08LA137

1 person was seriously injured.

The mechanic's improper maintenance installation of the No. 1 cylinder rocker arms which led to oil starvation and a loss of engine power.

Quoted verbatim from the NTSB record. This site does not paraphrase or interpret it.

Read the full NTSB narrative

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.

Quoted verbatim from the NTSB record.