What was found
DURING FLIGHT, THE AIRCRAFT BEGAN TO SHAKE VIOLENTLY. AFTER A PRECAUTIONARY LANDING IT WAS FOUND THAT APPROXIMATELY 4.5 INCHES OF THE NR 1 BLADE TIP HAD SEPARATED. A 1.1250 INCH CIRCUMFERENCE BY .0156 INCH DEPTH/NICK WAS LOCATED AT THE POINT OF SEPARATION. PROPAGATION WAS PROBABLY CAUSED BY EITHER EXCESSIVE STRESS DURING OVERHAUL OR FATIGUE. RECOMMENDATION: CLOSER EXAMINATION DURING OVERHAUL TO IDENTIFY STRESS RISERS OR FRACTURES.