What was found
WHILE PERFORMING MX, A CRACK WAS DISCOVERED IN THE OUTER SKIN OF THE TAILBOOM ON THE LT SIDE AT THE FORWARD ROW OF RIVETS THAT SECURED THE TAIL ROTOR GEARBOX HOUSING. THE CRACK APPEARS TO HAVE STARTED AT ONE OF THE RIVETS, EXTENDED TO ANOTHER AND WAS CONTINUING ON PAST THE 2ND RIVET. THE CRACK WAS APPROX 1.5" IN LENGTH. PRODUCT SUPPORT WAS NOTIFIED AND THEY DETERMINED THAT THE CRACK MADE THE TAILBOOM UNSERVICABLE AND THAT THE UPPER SKIN WOULD HAVE TO BE REPLACED.