81-26-02: Stabilizer Spar Tube Structure

81-26-02 SOCIETE NATIONALE INDUSTRIELLE AEROSPATIALE (SNIAS): Amendment 39-4278. Applies to Models SA360C and SA365C series helicopters certificated in all categories. Compliance is required as indicated. To improve fatigue resistance and prevent possible cracks in the tail boom stabilizer spar attachment structure and to detect possible cracks in the stabilizer spar, accomplish the following: (a) For Model SA360C series helicopters S/N up to and including 1034 and SA365C helicopter S/N 5003 only, comply with the following within 200 hours' time in service after the effective date of this AD unless already accomplished. Modify the tail boom at the stabilizer tube mount in accordance with Aerospatiale Service Bulletin No. 53.01 dated July 17, 1978, by installing modification AMS 365A.07.1310 or by installing an equivalent modification approved by Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Office. (b) For all Model SA360C seriesand SA365C series helicopters equipped with spar tubes, P/N 360A13.0012.01, comply with the following within 10 hours' time in service after the effective date of this AD unless already accomplished and thereafter at intervals not to exceed 50 hours' time in service from the last inspection. (1) Remove the stabilizer spar tube from the helicopter and inspect the spar tube for cracks at the location of the weld beads for spacers and spar tube junction using a dye penetrant or equivalent inspection method. (2) If the spar tube is cracked, discard the tube and install a serviceable tube before further flight and conduct repetitive inspections as specified in subparagraph (b). (c) Equivalent means of compliance with the AD may be approved by the Chief, Aircraft Certification Staff, FAA, Europe, Africa, and Middle East Offices. (Aerospatiale SA360 Dauphin Service Bulletin No. 05.01 pertains to tail boom inspections. Telex Service 05-06 Dauphin pertains to the stabilizer spar tube inspections. Modification No. AMS07-3255 may improve the spar tube to spacer weld joint.) This amendment becomes effective December 21, 1981.