What was found
EN-ROUTE THE PILOT NOTICED THE RT ENG OIL PRESS WARNING LIGHT ILLUMINATED & THE OIL PRESS INDICATION WAS AT 60 PSI & IN THE YELLOW ARC. THE PILOT REDUCED THE POWER ON THE RT ENG. DECLARED AN EMER, DIVERTED & LANDED WITHOUT INCIDENT. INSPECTED THE RT ENG, OIL LEVEL WAS 4 QRTS LOW. NO OIL LEAKS WERE PRESENT. INSPECTED THE OIL SYS BREATHER SCAT TUBE & FOUND THE INNER WALL COLLAPSED. REPLACED OIL VENT SCAT TUBE & PERFORMED ENG RUNS & OPERATIONAL CHECKS. ALL CHECKS WERE NORMAL.