JUPITER, FL, USA
N4480F
PIPER PA-28-151
DURING CRUISE FLT ABOUT 1/2 MILE OFFSHORE AT AN ALT OF 500 FT, THE PLT STATED THAT HE HEARD A KNOCKING SOUND & THE ENG LOST POWER. UNABLE TO MAINTAIN ALT, HE DITCHED THE ACFT. THE ACFT WAS RECOVERED & THE ENG WAS REMOVED FOR FURTHER EXAM. EXAM OF THE ENG REVEALED THAT THE NO.2 CYL EXHAUST VALVE FAILED DUE TO A WORN VALVE GUIDE. THE INTERNAL DIAMETER OF THE VALVE GUIDE AT THE TOP MEASURED .539' & THE BOTTOM MEASURE .563'. FACTORY SPECIFICATIONS ARE .4985' TO .4995'. THE ENG LOGBOOKS WERE INSIDE THE ACFT & WERE NOT RECOVERED.
PARTIAL LOSS OF ENGINE POWER DUE TO FAILURE OF AN EXHAUST VALVE, DUE TO A VALVE GUIDE THAT WAS WORN BEYOND SPECIFICATIONS.
Source: NTSB Aviation Accident Database
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