62-25-02 DOUGLAS: Amdt. 510 Part 507 Federal Register November 28, 1962. Applies to All Models DC-6 and DC-7 Series Aircraft. \n\n\tCompliance required as indicated. \n\n\tDue to failure of a main gear shock strut cylinder and numerous cases of cracks in the 0.125-inch radii next to the torque link lugs on the cylinders, and on the piston tube axle fittings, the following shall be accomplished. \n\n\t(a) DC-6 Series Aircraft. \n\n\t\t(1) With 30,000 or more hours' time in service as of the effective date of this AD shall be inspected and reworked in accordance with paragraphs (c) and (d) within the next 200 hours' time in service after the effective date of this AD, unless already accomplished within the last 100 hours' time in service, and thereafter within each 300 hours' time in service from the last inspection. \n\n\t\t(2) With less than 30,000 hours' time in service as of the effective date of this AD shall be inspected and reworked in accordance with paragraphs (c) and (d) priorto the accumulation of 30,200 hours' time in service, and thereafter within each 300 hours' time in service. \n\n\t(b) DC-7 Series aircraft. \n\n\t\t(1) With more than 15,000 hours' time in service as of the effective date of this AD shall be inspected and reworked in accordance with paragraphs (c) and (d) within the next 200 hours' time in service after the effective date of this AD, unless already accomplished within the last 100 hours' time in service, and thereafter within each 300 hours' time in service from the last inspection. \n\n\t\t(2) With less than 15,000 hours' time in service as of the effective date of this AD shall be inspected and reworked in accordance with paragraphs (c) and (d) prior to the accumulation of 15,200 hours' time in service, and thereafter within each 300 hours' time in service. \n\n\t(c) Inspect, using dye penetrant, or magnetic particle, or FAA approved equivalent, for cracks in the 0.125-inch radii at the edges of the torque link lugs in the main landing gear shock strut cylinder and the piston tube axle fitting. \n\n\t(d) If cracks are found, they may be removed by reworking the 0.125-inch radius in accordance with the instructions contained in Douglas Service Engineering letter C1-78-M1281/DJW dated April 20, 1962, and sketches 498A and 498B attached thereto or Douglas Service Engineering Letter C1-78-140/DJW, dated January 30, 1963, and sketches 534A, 534B, 534C, 534D and 534E attached thereto. If cracks cannot be removed without exceeding limits specified in the Douglas sketches, the gear must be replaced prior to further flight. Parts that can be reworked, and those in which no cracks are found, must be repainted with zinc chromate primer and aluminized lacquer before they are returned to service. \n\n\t(e) When the 0.125-inch radii at the edges of the torque link lugs on the strut cylinders and axle fittings have been enlarged to 0.250-inch radii, holding the tolerances described in Douglas Service Engineering letter C1-78-M1281/DJW dated April 20, 1962, and sketches 498A and 498B attached thereto, or Douglas Service Engineering letter C1-78-140/DJW, dated January 30, 1963, and sketches 534A, 534B, 534C, 534D and 534E attached thereto, and the parts are refinished as described in (d), the repetitive inspections required herein may be discontinued. \n\n\t(f) Upon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering & Manufacturing Branch, FAA Western Region, may adjust the repetitive inspection intervals specified in this AD to permit compliance at an established inspection period of the operator if the request contains substantiating data to justify the increase for such operator. \n\n\t(Douglas Service Engineering letter C1-78-M1281/DJW dated April 20, 1962, and sketches 498A and 498B attached thereto, or Douglas Service Engineering letter C1-78-140/DJW, dated January 30, 1963, and sketches 534A, 534B, 534C, 534D, and 534E attached thereto, covers thissame subject.) \n\n\tThis directive effective November 28, 1962. \n\n\tRevised April 4, 1963.