51-09-02 DOUGLAS: Applies to All Models DC-4 and C54-DC Series Aircraft. \n\n\tCompliance required as indicated. \n\n\tA.\tTo be accomplished at intervals not to exceed 2,000 hours of flight time. Torque check all empennage control surface hinge bolts by first making a visual check of the slippage stripe across the nut and the adjacent area for signs of any relative motion and then applying a tightening force to the nut equal to the minimum torque specified in the Douglas Maintenance Manual for the nut and bolt combination. If the nut does not move with the application of this force and the condition of the stripe indicates no previous movement, the assembly may be left intact. When any looseness is found, the assembly should be removed and thoroughly inspected. \n\n\tB.\tTo be accomplished at each major overhaul period. In addition to the control surface hinge bolts mentioned in part A remove the nuts from all rudder and elevator bracket attaching bolts and rudder and elevator hinge eyebolts. All nuts, bolt or stud threads, and mating surfaces must be cleaned of dirt, grease, oil or dye and thoroughly dried. All parts should be checked for wear and replaced as necessary. Upon reassembly, all nuts should be torqued to the recommended values specified in the Douglas Maintenance Manual for the particular model airplane. All torqued or retorqued bolts should be identified by a narrow painted line across the nut and adjacent surface so any movement of the nut will be readily discernible. This marking should be done as soon as possible after torquing. Bolt heads should not be torqued or retorqued unless it is impossible to reach the nut because of inaccessibility. If it should be necessary to torque or retorque the bolt head, it should be marked in the same manner as described for the nut. \n\n\tC.\tAirline operators with FAA-accepted maintenance inspection programs need only torque check 15 percent of fleet or minimum of two airplanes, whichever is greater, at each 2,000-hour period or in multiples of major inspection closest to 2,000 hours. This period may be increased in 1,000-hour steps until the major aircraft overhaul period is reached provided no defects are found. Thereafter, the torque check shall be accomplished on each aircraft at the aircraft major overhaul period. Where the FAA-accepted maintenance inspection program includes procedures equivalent to this Airworthiness Directive and above deviation, the FAA-accepted maintenance program may be followed in lieu of this Airworthiness Directive. \n\n\tThis supersedes AD 47-27-03.