68-04-04 R2 BRANTLY: Amendment 39-557 as amended by Amendment 39-3568 is further amended by Amendment 39-4552. Applies to Model B-2, B-2A, and B-2B helicopters, certificated in all categories. \n\n\tFor tail rotor blades, P/N 111-11, with 100 or more hours' time in service after February 27, 1968, compliance required prior to further flight, unless already accomplished, and, thereafter, at intervals not to exceed 100 hours' time in service from the last inspection. For tail rotor blades, P/N 111-11A, with 300 or more hours' time in service after August 15, 1979, compliance required prior to further flight, unless already accomplished, and, thereafter, at intervals not to exceed 300 hours' time in service from the last inspection. \n\n\tTo prevent failures of the tail rotor blade at the spar retention areas, accomplish the following: \n\n\t(a)\tRemove, clean, and mark the tail rotor blades in accordance with Brantly Service Bulletin, SB No. B2B-68-1, dated February 14, 1968, and accomplish the following inspections: \n\n\t\t(1)\tVisually inspect the inside and outside of the spars of the tail rotor blades particularly at the inside bearing boss radius for evidence of pitting corrosion. If corrosion is detected, replace the blade assembly before further flight with an airworthy part. \n\n\t\t(2)\tInspect the inside and outside of the spars of the tail rotor blades particularly at the inside bearing boss radius for evidence of cracks using dye penetrant procedures as indicated in Figure 1 of Brantly Service Bulletin, SB No. B2B-68-1, dated February 14, 1968, or use an equivalent method approved by the Manager, Aircraft Certification Division, FAA, Southwest Region, Fort Worth, Texas 76101. If a crack is detected, replace the blade assembly before further flight with an airworthy part. \n\n\t(b)\tAfter the tail rotor blades have been inspected or replaced with an airworthy part as provided in paragraphs (a)(1) and (a)(2) of this Airworthiness Directive, assemble them in accordance with Brantly Service Bulletin, SB No. B2B-68-1, dated February 14, 1968. \n\n\t(c)\tTo prevent confusion during subsequent inspections of tail rotor blades due to similarity between tail rotor blade assembly, PN 111-11, and assembly, PN 111-11A, use a permanent marking ink or equivalent acceptable for aluminum aircraft components to mark the tail rotor blade assembly with the proper part number identification (see Fig. 1 for dimensions that determine the part configuration). \n\n\t(d)\tIn order to facilitate inspection of the tail rotor blade spar retention area, do not repaint the spar retention area. \n\n\t(e)\tThe requirements of paragraphs (c) and (d) above must be implemented no later than the next compliance with paragraph (a) of this AD after February 14, 1983. \n\n\tAmendment 39-557 became effective February 27, 1968, to all persons except those to whom it was made effective on receipt of airmail letter dated February 14, 1968. \n\n\tAmendment 39-3568 became effective October 28, 1979. \n\n\tThis Amendment 39-4552 becomes effective February 14, 1983.