Piper J3C-65 N5985V

Summary

On 3 August 1997 at about 16:30 local time, a Piper J3C-65 registered N5985V was involved in an accident near Castle Rock, Colorado, United States. One person was on board and nobody was injured. The aircraft was substantially damaged. The NTSB has published a probable cause for this accident; it is quoted in full below.

Date

3 August 1997 at 16:30

Classification

Accident

Location

Castle Rock, Colorado, United States

Coordinates

39.3701, -104.8495

Aircraft

Piper J3C-65

Registration

N5985V

Category

Airplane

Engines

1

Operator

Not recorded

Operating rule

Part 91: General Aviation

Purpose of flight

Personal

Phase of flight

Not recorded

Route

Englewood → Unknown

Aircraft damage

Substantial

Weather

VMC

Light

Day

NTSB number

FTW97LA298

Nobody was injured.

A partial loss of engine power due to a cylinder exhaust valve jammed in the open position from excessive carbon deposits. A factor was the lack of suitable terrain on which to make a forced landing.

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

Read the full NTSB narrative

While in cruise flight, engine RPMs dropped from 2,350 to 1,700, and the airplane began to descend. The pilot made a forced landing in an open, uneven field. The landing gear was sheared off and the fuselage was buckled. Postaccident examination of the engine disclosed the no. 4 cylinder exhaust valve was jammed in the open position. The valve stem and guide were coated with 'gummy black deposits.' The pilot had a similar accident on July 22, 1995 (FTW 95-L-A312). In that accident, the jammed exhaust valve was attributed to excessive carbon deposits from high octane aviation gasoline usage in a low compression engine.

Quoted verbatim from the NTSB record.