61-18-01 BOEING: Amdt. 326 Part 507 Federal Register August 24, 1961 as amended by amendment 39-1002. Applies to Boeing 707 Series Aircraft Serial Nos. 17586-17652, 17658- 17690, 17692-17712, 17718-17724, 17903-17906, 17918-17919, 17925-17930, 18012 and 18054 and Boeing 720 Series Aircraft Serial Nos. 17907-17917, 18013-18020, 18023, and 18041 as indicated. \n\n\tDue to failure in a main landing gear trunnion support, the following inspections, contained in paragraphs (a), (b), and (c), are required on all specified 707 Series aircraft until paragraph (d) has been accomplished. Paragraph (e) is required on all specified 707 Series aircraft after paragraph (d) is accomplished and on all specified 720 Series aircraft. \n\n\t(a) Within the next 200 hours' time in service, unless already accomplished within the last 150 hours' time in service, and thereafter at every 350 hours' time in service: \n\n\t\t(1) Clean the web, upper and lower chord areas and aft flanges on the inboard and outboard side of 220,000 p.s.i. heat treat steel main landing gear trunnion support rib and conduct a visual inspection of the cleaned areas for evidence of cracks.\n \n\t\t(2) Clean and visually, or radiographically, inspect the forward trunnion support fitting for evidence of cracks on the forward and aft side in the region of the bearing collar. \n\n\t\t(3) If evidence of cracks is found in (a)(1) or (a)(2) above, conduct more detail inspections using fluorescent dye penetrant at temperatures of 50 degrees F. or above, X-ray, or equivalent. \n\n\t(b) Within the next 35 hours' time in service, unless already accomplished within the last 30 hours' time in service and thereafter at every 125 hours' time in service, clean the main landing gear aft trunnion bearing support, paying particular attention to the areas listed below, and conduct a fluorescent dye penetrant inspection or equivalent for cracks; \n\n\t\t(1) Area around the barrel nut hole, both forward and aft sides. \n\n\t\t(2) A strip 1/2-inch wide around upper bearing support, from the upper barrel nut to lower 1.31 diameter inboard (tension) bolt hole, on aft side. \n\n\t\t(3) A strip 1/2-inch wide around upper bearing, from upper barrel nut to trunnion support rib, on forward side. \n\n\t(c) If cracks exceeding allowable lengths specified in the latest revision of Boeing Service Bulletin No. 859 (R-2 or later) are found during inspections (a) and (b), the affected components must be replaced or repaired in accordance with FAA approved Boeing procedures prior to further flight. When cracks less than the maximum allowable lengths specified in S.B. 859 (R-2 or later), are found, the following shall be accomplished: \n\n\t\t(1) Stop drill in accordance with S.B. 859 (R-2 or later) instructions and inspect for crack progression at each 350 hours' time in service after stop drilling. If cracks progress beyond the stop drilled hole, contact Boeing for FAA approved Boeing repair procedures to be incorporated prior to further flight. \n\n\t\t(2) If cracks are not accessible for stop drilling prior to further flight FAA approved Boeing instructions must be obtained for the required inspection intervals and procedures for the specific crack location and length. \n\n\t(d) Unless already accomplished at the factory or by the operator within the next 3,500 hours' time in service conduct the following detail inspections and rework as indicated: \n\n\t\t(1) Remove the main landing gear and trunnion in accordance with BAC Maintenance Manual Procedure. \n\n\t\t(2) Remove all nuts and washers along the periphery of the trunnion support rib. \n\n\t\t(3) Rework the main landing gear trunnion support fittings per the latest revision of FAA approved S.B. No. 874 (August 9, 1960, or later). \n\n\t\t(4) Following the rework, clean the aft and forward trunnion support fittings and perform a thorough magnetic particle and visual inspection for cracks. \n\n\t\t(5) Conduct a thorough visual inspection for evidence of cracks in the main landing gear trunnion support rib and flanges using a low power (2- or 3- power) wide-field (at least 2 1/2-in diameter field of view) magnifying glass or FAA approved equivalent, and covering every square inch of exposed area (both sides) with special emphasis around each and every bolt hole on all flanges and boundaries. Any suspected discrepancy should be confirmed with dye penetrant or equivalent after paint removal. \n\n\t\t(6) If cracks are found during inspections (d)(1) through (d)(5), the affected components must be replaced or repaired in accordance with FAA approved Boeing procedures prior to further flights. \n\n\t\t(7) After reinstalling nuts and washers in accordance with Part I, Subparagraph (e), S.B. 859 (R-2 or later), measure the gap between the upper and lower flanges and skin at several points along the forward 8 inches of each flange using a thickness gage. See latest revision of FAA approved S.B. 859 (R-2 or later) Part I, Subparagraph (f) for instructions if any gap exceeds 0.02 inch. \n\n\t(e) The following repetitive inspections are required on all specified 707 Series aircraft upon completion of inspections and rework outlined in (d) and on all specified 720 Series aircraft. These provisions of paragraph (e), (1) and (2) may be deleted from the 720 aircraft inspection intervals, provided that no cracks have been found in the steel main landing gear trunnion support rib. If cracks are found or have been found in the rib assembly and repaired per Service Bulletin No. 859 (R-2) the repetitive inspections of paragraph (e), (1) and (2) shall apply. \n\n\t\t(1) Every 420 hours' time in service, visually inspect the forward and aft trunnion support fittings for cracks. \n\n\t\t(2) Every 840 hours' time in service visually inspect the web and flanges on the inboard and outboard sides of the trunnion support rib for cracks. \n\n\t\t(3) Every 5,000 hours' time in service clean all areas of the main landing gear trunnion support assembly ofdirt and grease using Naphtha TT-N-95 or BNS 3-2. After cleaning, together with mirror and lighting as required, and using a low powered (2- or 3-power) wide-field (at least 2 1/2-inch diameter field of view) magnifying glass, or FAA approved equivalent, conduct the following inspections as indicated: \n\n\t\t\t(i) Visually inspect the web and flanges on the inboard and outboard sides of the trunnion support rib for evidence of cracks. \n\n\t\t\t(ii) Visually inspect the forward trunnion support fitting for evidence of cracks of the forward and aft sides in the region of the bearing collar. \n\n\t\t\t(iii) Visual inspect the aft trunnion support fitting for evidence of cracks. \n\n\t\t\t(iv) Crack indications found in (i), (ii), and (iii) should be confirmed by dye penetrant inspection. Allowable crack limits and FAA approved rework information for (i) is shown in FAA approved Service Bulletin No. 859 (R-2 or later) (Figure 2). \n\n\t\t(4) If cracks are found in the inspections of (e), the affected components must be replaced or repaired in accordance with FAA approved Boeing procedures prior to further flight. \n\n\t\t(5) Upon request of the operator, an FAA maintenance inspector, subject to approval of the Chief, Engineering and 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(Boeing Service Bulletin Number 859 (R-2) pertains to this subject.) \n\n\tThis supersedes AD 60-08-01. \n\n\tAmendment 326 effective September 23, 1961. \n\n\tRevised January 26, 1962. \n\n\tRevised October 26, 1963. \n\n\tThis amendment (39-1002) becomes effective June 6, 1970.