What was found
WHILE IN ROUTE TO KMLI, THE FLIGHT CREW REPORTED RIGHT ENGINE OIL PRESSURE DECREASED AND THE AIRCRAFT YAWED RIGHT. THE RIGHT ENGINE WAS SHUT DOWN AND SECURED AND EMERGENCY WAS DECLARED. THE AIRCRAFT LANDED WITHOUT INCIDENT IN KBMI. MAINTENANCE INSPECTED AND FOUND RIGHT PROP SHAFT SEAL DAMAGED. REMOVED RIGHT PROP AND REPLACED PROP SHAFT SEAL AND REINSTALLED RIGHT PROP. CLEANED ENGINE AND COWLINGS, THEN RAN ENGINE AT POWER FOR 10 MIN. VERIFIED NO LEAKS WITH OIL PRESSURE AND OTHER ENGINE PARAMETERS WITHIN LIMITS.