78-03-04 BOEING: Amendment 39-3136. Applies to all Boeing 707-100/-100B/-200 series airplanes, certificated in all categories upon the accumulation of 20,000 landings. \n\tAccomplish the following: \n\tA.\tWithin the next 750 landings, unless accomplished within the last 750 landings, and thereafter at intervals not to exceed 1500 landings, X-ray inspect the upper rear spar chord horizontal leg and adjacent wing skin from the side of the body at BBL 70.5 to WS274 in accordance with Boeing Service Bulletin 3304, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. Wing skins or rear spar chords found cracked are to be repaired prior to further flight in accordance with paragraph B. \n\tB.\tRepair in accordance with 1 or 2 below as applicable, prior to further flight except that the airplane may be flown in accordance with FAR 21.197 to a base where the repair can be performed: \n\t\t1.\tAirplanes with skin cracks near the rear spar which do not extend beyond the fastener pattern of stringer No. 1 may continue in service for a maximum of 750 additional landings, subject to the following conditions: \n\t\t\ta.\tCrack ends must be stop drilled per Boeing Service Bulletin 3304. \n\t\t\tb.\tIf crack ends in a fastener hole, the hole must be inspected per Boeing Service Bulletin 3304 to assure there is no crack progression beyond fastener hole, then an additional 1/16" oversize must be made and an oversize fastener installed. \n\t\t\tc.\tEddy current inspection per Boeing Service Bulletin 3304 of crack ends must be conducted at intervals not to exceed 50 landings. Any crack progression requires repair in accordance with 2 below prior to further flight. \n\t\t\td.\tCracks must be permanently repaired within 750 landings in accordance with 2 below. \n\t\t2.\tRepair in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. \n\tC.\tFor the purpose of complying with this AD, subject to acceptance by the assigned FAA maintenance inspector, the number of landings may be determined by dividing each airplane's hours time-in-service by the operator's fleet average from takeoff to landing for the airplane type. \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\tAll persons affected by this directive who have not already received these documents from the manufacturer, may obtain copies upon request to Boeing Commercial Airplane Company, P.O. Box 3707, Seattle, Washington 98124. These documents may also be examined at FAA Northwest Region, 9010 East Marginal Way South, Seattle, Washington 98108. \n\n\tThis AD supersedes AD 77-06-03. \n\tThis amendment becomes effective March 1, 1978.