Primary finding
Probable cause
Fatigue failure of the engine no.1 valve spring that jammed the intake valve open resulting in partial loss of engine power.
Investigator assessment
Analysis narrative
While in cruise flight the engine lost power and the pilot attempted a forced landing at night to an interstate highway. During approach the airplane hit wires. Examination of the engine after the accident revealed fatigue failure of the no.1 cylinder outer intake valve spring that jammed the inner spring resulting in the valve being jammed open.
Source record
Factual narrative
On December 31, 1994, about 1820 eastern standard time, N4300S, a Piper PA-28-161, registered to Air Orlando Sales Inc., crashed in Lakeland, Florida, while on a 14 CFR Part 91 personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The airplane was substantially damaged and the commercial pilot and one passenger received no injuries. The flight originated from the Lakeland Airport about 15 minutes earlier. The pilot noted a loss of engine power and initiated a forced landing to the median of an interstate highway. The airplane struck wires on approach. Examination by the FAA revealed the No. 1 cylinder outer intake valve spring failed. Further examination of the spring revealed failure signatures consistent with fatigue. -