What was found
(CAN) DURING POST FLIGHT WALK AROUND OF AC FOLLOWING ARRIVAL, CREW IDENTIFIED CONSIDERABLE QTY OF LUBRICATING OIL HAD BEEN LIBERATED FROM LT PROPELLER. CREW TERMINATED FLIGHT AND CALLED FOR ENGINEERING ASSISTANCE. ENGINEERING INVESTIGATION REVEALED FAILURE OF PROP HUB TO PROP BLADE SEAL AT NR 4 BLADE POSITION. NEW SEAL INSTALLED, FOLLOWING CONSIDERABLE CLEAN UP, AC WAS RETURNED TO SERVICE. INSP OF REMOVED SEAL REVEALED SEAL TO BE FOR A 14SF TYPE PROP WITH A 14RF TYPE PROP GLAND SPRING SUPPLIED. SEAL IS FULLY TRACEABLE AND WAS SUPPLIED TO AIRLINE BY MFG AFTER ALLEGEDLY BEING INSPECTED BY MFG FOR CORRECT CONFORMANCE OF SPRING ASSY. 14RF GLAND SPRING IS OF SMALLER DIAMETER WHEN COMPARED TO 14SF GLAND SPRING.