78-01-04 BOEING: Amendment 39-3112 as amended by Amendment 39-3132. Applies to all Boeing 707-300/400/300B/300C series airplanes upon the accumulation of, or with more than 8,000 landings. \n\tVisually inspect the horizontal stabilizer center section rear spar upper chord for cracks between terminal fittings in accordance with Boeing Service Bulletin 3331 or with the method specified in paragraph B at the time interval specified in paragraph A below. Chords found cracked are to be reworked in accordance with one of the methods noted in paragraph C or replaced with a chord of the same part number prior to further flight. \n\tA.\tInspect within the next 375 landings after the effective date of this AD and thereafter at intervals not to exceed 375 landings. Report all cracks found during the initial inspection to the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, noting airplane identification, hours time in service, crack locations and magnitude. \n\tB.\tInspection may be accomplished by gaining access to the upper rear surface of the center section and examining the exposed surfaces of the upper chord using a bright light and a mirror at the aft upper and lower surfaces of the chord. If indications of a crack are found, eddy-current or penetrant inspection should be used to confirm presence of crack. \n\tC.\tRework in accordance with one of the following: \n\t\t1.\tAn FAA approved repair provided by the Boeing Company. \n\t\t2.\tA method approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. \n\tD.\tWith permission of the Chief, Engineering and Manufacturing Branch, FAA Northwest Region, the airplane may be flown in accordance with FAR 21.197 to a base where the inspection or repair can be accomplished. \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 notalready 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\tAmendment 39-3112 became effective January 15, 1978. \n\tThis Amendment 39-3132 becomes effective March 1, 1978.