What was found
RIGHT REAR TIRE RIGHT TRUCK AXLE FAILED PRIOR TO TAKEOFF. RIGHT REAR AXLE SHEARED OFF. SUPPLEMENTAL DATA UPDATE A CHROME GRINDING DEFECT ON THE 4.5 INCH OUTER DIAMETER CAUSED CIRCUMFERENTIAL CRACKING AND THE EVENTUAL FAILURE OF THIS AXLE. THE GRINDING DEFECT HAS CHARACTERISTICS CONSISTENT WITH A GRINDING WHEEL PLUNGE MANEUVER. THIS DEFECT WAS IN THE MAXIMUM BENDING STRESS LOCATION FOR THIS AXLE, A MOST CRITICAL AND WORST PLACE FOR ANY DEFECT ON THIS PART. REPLACED AXLE.