Info Centre >> Fuel and Lube Oil Technical Manual >> 7. Lube Oil - Test Results >> 7.9 Directory of Bearing Failures >> Insolubles and Debris
1 -fine abrasive wear - similar to 74 but less pronounced
2 - circumferential scores due to a few large particles.
3 - multiple fine scoring from entrained debris (overloaded filter has caused the oil flow to bypass the filter hence debris removal was minimal.