What was found
DURING CLIMB THE RPM DROPPED AND POWER WAS LOST FORCING THE AIRCRAFT TO LAND IN A FIELD. INSPECTING THE ENGINE ON CYLINDER NR 2, THE 3 ROCKER SHAFT RETAINING BOSSES WERE FOUND BROKEN AND THE INTAKE AND EXHAUST ROCKER'S WERE NO LONGER OPENING THE VALVES. THE ENGINE WAS O/H IN 1981 AND 1992. IN 1994, AD 94-05-05 R1 WAS ISSUED WHICH REQUIRES THE ROCKER SHAFT BOSSES TO BE INSPECTED FOR CRACKS AT EACH CYLINDER REMOVAL. ONLY CYLINDER 4 HAD BEEN REMOVED IN 2007 AND INSPECTED. TIME SINCE LAST MAJOR O/H 1087 HOURS AND 24 YEARS.