What was found
DURING ROUTINE INSPECTION, DISCOVERED HARILINE CRACK IN SKIN. SUBMITTER SUGGESTED MORE FREQUENT CHADWICK BALANCE & TRACK OR OTHER FORM OF VIBRATION TEST AT OR OF TALL ROTOR BLADES AS THIS HIGH FREQUENCY VIBRATION, WHICH RESULTS FROM TAIL ROTOR OUT OF BALANCE CONDITION, CAN CAUSE THESE CRACKS. ALSO, CONTINUED DISCRETIONAL, EXTREMELY VIGILANT INSPECTION OF SURROUNDING AREA FOR IMPENDING SKIN CRACKS LEADING TO CASTING FAILURE AT TAIL ROTOR GEARBOX MOUNT. (X)