What was found
RIGHT ENGINE OIL TEMP TO 145C AND OIL PRESSURE DROPPED TO 40-45 PSI TOP OF DESCENT INTO KIX. SHUT DOWN ENGINE. NR 1 BEARING FAILURE. THIS IS THE MAIN THRUST BALL BEARING SUPPORTING THE N1 ROTOR. OUTER RACE HEAVILY SPALLED THROUGH 100¡ ARC. ONE BALL HEAVILY SPALLED; ALL OTHERS, LIGHT-MODERATE SPALLING. CAGE FRACTURED AXIALLY THROUGH ONE BALL POCKET. NO SPALLING ON INNER RACES. BEARING IS PRE PRATT & WHITNEY SERVICE BULLETIN PW4G-112-72-212 PART NUMBER. BEARING WILL BE REPLACED WITH POST SB-212 PN WHICH HAS INCREASED DURABILITY. NOTE: ENGINE THRUST BALANCE SYSTEM WAS CONFIRMED TO BE FUNCTIONING NORMALLY.