82-01-09 BOEING: Amendment 39-4299. Applies to Model 737 series airplanes, certificated in all categories, listed in Boeing Alert Service Bulletin No. 737-53A1042 Revision 3, or later FAA approved revision. \n\n\tTo detect, prevent, arrest, and/or repair damage due to corrosion in the lower body skins, accomplish the following: \n\n\tA.\tWithin 30 days time-in-service after the effective date of this AD, unless accomplished within the last 60 days time-in-service, and thereafter at intervals not to exceed 90 days since the last inspection, inspect the exterior body skin from body station 360 to 540 between stringers 26 right and 26 left and from body station 727 to 1016 between stringers 25 right and 25 left including areas covered by fairings for skin cracks or dished/deformed or popped rivet heads. If any of these defects are noted, prior to further flight, accomplish 1 or 2 below: \n\n\t\t1.\tInternally inspect area of distress. Clean up corrosion, repair or replace damaged structure in accordance with Section III, Part II, III, or IV of Boeing Service Bulletin 737-53A1042, Revision 3 or a later FAA approved revision or the 737 Structural Repair Manual and saturate the internal structure surface with BMS3-23 or equivalent. \n\n\t\t2.\tPerform the interim repair of Boeing Service Bulletin 737-53A1042R3NSC1, however, the repair must be replaced in accordance with 1 above within one year after installation. \n\n\tThis inspection is to continue until the inspection of paragraph B. is accomplished.\n \n\tB.\tWithin 12 months time-in-service after the effective date of this AD, unless accomplished within the last 12 months time-in-service, and at intervals not to exceed 24 months time-in-service, visually inspect the structure internally and externally for corrosion and cracks from body station 360 to 540 between stringers 26 right and 26 left and from body station 727 to 1016 between stringers 25 right and 25 left. Clean up corrosion, repair or replace damaged structure inaccordance with Boeing Service Bulletin 737-53A1042, Revision 3 or a later FAA approved revision or the 737 Structural Repair Manual and saturate the internal structure surface with BMS3-23 or equivalent. \n\n\tC.\tReplacement of all affected skin panels in accordance with Section III Part IV of Boeing Service Bulletin 737-53A1042 or a later FAA approved revision constitutes terminating action for this AD. \n\n\tD.\tAlternate means of compliance or other actions which provide an equivalent level of safety may be used when approved by the Chief, Seattle Area Aircraft Certification Office, FAA Northwest Mountain Region. \n\n\tE.\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Seattle Area Aircraft Certification Office, FAA Northwest Mountain Region, may adjust the repetitive inspection intervals in this AD, if the request contains substantiating data to justify the increase for the operator. \n\n\tF.\tSpecial flight permits may be issued in accordance with FAR 21.197 and 21.199 to operate airplanes unpressurized to a base in order to comply with the requirements of this AD.\n \n\tThe manufacturer's specifications and procedures identified and described in this directive are incorporated herein and made a part hereof pursuant to 5 U.S.C. 552(a)(1). \n\n\tAll persons affected by this directive who have not already received the above specified alert service bulletin from the manufacturer may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98108. \n\n\tThis Amendment becomes effective January 18, 1982.