What was found
DURING CRUISE, THE EGT INDICATION FOR THE NR 2 CYL OF THE RT ENGINE DROPPED TO ZERO. THIS WAS ACCOMPANIED BY VIBRATION, SLIGHT LOSS OF MANIFOLD PRESSURE AND A SLIGHT DECREASE IN THE CHT AND EGT INDICATIONS FOR CYLINDERS NR 4 AND NR 5. RETURNED TO DEPARTURE BASE. ENGINE WAS NOT SHUT DOWN. UPON COMPRESSION CHECK, NR 2 CYLINDER WAS FOUND WITH ZERO COMPRESSION. A BORESCOPE INSPECTION REVEALED A FAILURE OF THE EXHAUST VALVE. INSPECTION OF THE OTHER CYLINDERS ALSO SHOWED CONSIDERABLE DAMAGE TO NR 5 CYL AND MINOR DAMAGE TO SEVERAL OTHERS. WHEN INDUCTION SYSTEM BALANCE TUBE WAS REMOVED, A PIECE OF VALVE WAS FOUND. (WP272003B2874)