What was found
ON SHORT APPROACH TO MÉRIDA, APPROXIMATELY 300 AGL AND WITH APPROACH POWER SELECTED, THE RT ENGINE BEGAN SIGNIFICANT POWER SURGES BETWEEN IDLE POWER AND MAXIMUM POWER. EGT, TORQUE, RPM, AND FUEL FLOW WERE ALL SURGING UNCONTROLLABLY AND IN CONCERT. MAINTENANCE TROUBLESHOT AND FOUND RT ENGINE PROPELLER GOVERNOR CASE LEAKING OIL. R & R RT ENGINE PROP GOVERNOR, OPERATIONAL AND LEAK CHECKS GOOD.