What was found
SEVERE ENGINE ROUGHNESS OCCURRED WHILE IN FLIGHT. AN OFF AIRPORT LANDING WAS MADE WITH NO DAMAGE TO AIRCRAFT AND NO INJURIES. NR 1 CYLINDER FOUND TO HAVE NO COMPRESSION. FOUND THAT PN 17726 VALVE SPRING WASHER HAD FAILED ALLOWING INTAKE VALVE TO DROP INTO CYLINDER NR 1. ENGINE TSMOH 1106. TIME SINCE TOP OVERHAUL 418.45. I WAS UNABLE TO DETERMINE IF PART WAS REPLACED AT MAJOR OVERHAUL OR TOP OVERHAUL. THIS REPORT IS SUBMITTED AS A CORRECTION TO THE DIFFICULTY DATE. PREVIOUS REPORT HAD DATE OF 11/19/2003. ACTUAL DATE OF OCCURENCE WAS 10/16/2003.