80-24-01: Tailcone

80-24-01 ROBINSON HELICOPTER: Amendment 39-3975. Applies to Model R-22 helicopters serial numbers 0002 through 0082 certificated in all categories. Compliance required as indicated unless already accomplished. To prevent possible loss of the tailcone resulting from supporting framework tube or tube weldment fractures, accomplish the following: (a) Unless accomplished within the previous 90 hours' time in service, in accordance with the methods of Robinson Helicopter Company Service Bulletin B-4 dated September 19, 1980, hereinafter referred to as SB B-4, prior to the accumulation of 100 hours' time in service or within 10 hours time in service from the effective date of this AD and thereafter at intervals not to exceed 100 hours' time in service since the last such inspection, dye penetrant inspect the tubes and weldments for cracks per methods of, and in the areas identified as items 1 through 4 of the figure of SB B-4. (b) If no cracks are found the rotorcraft may be returned to service provided that, on reassembly, the hardware as discussed in paragraphs 7 and 8 of the section of SB B-4 entitled "Removal of the A 023 Tailcone Assembly" is replaced with the following identical new parts: NAS - 679-A4 NUT (5 each) NAS 1304-22 Bolt (4 each) NAS 1304-3 Bolt (1 each) PAL NUTS (5 each) (c) If cracks are detected as a result of the inspections of paragraph (a) of this AD, prior to further flight notify the Chief, Aircraft Engineering Division, FAA Western Region for instructions and disposition of the part. Exact location and extent of crack must be made available to the FAA. (d) Special flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes to a base for the accomplishment of inspections required by this AD. (e) Alternative inspections, modifications or other actions which provide an equivalent level of safety may be used when approved by the Chief, Aircraft Engineering Division, FAA Western Region. This amendment becomes effective November 24, 1980.