64-15-01\tBOEING: Amdt. 756 Part 507 Federal Register July 3, 1964. Applies to All Models 707-300B and 707-300C Series Aircraft Listed in Boeing Service Bulletin No. 1962(R- 1). \n\tCompliance required as indicated. \n\tCracks have occurred in the flange of the left and right fillet flap drive support assembly, P/N's 65-22244-1 and -2. In each instance the crack originated in the lower inboard flange area of the subject assemblies. To correct this condition, accomplish the following: \n\t(a)\tWithin 30 hours' time in service after the effective date of this AD, unless already accomplished within the last 100 hours' time in service, and thereafter at periods not to exceed 130 hours' time in service from the last inspection, visually inspect the upper and lower inboard and outboard flanges of the fillet flap drive screw support assemblies, P/N's 65-22244-1 and -2 for cracks. Parts found to be cracked shall be repaired before further flight in accordance with either paragraph (b), (c), or(d). \n\t(b)\tRepair cracks before further flight in accordance with Boeing Service Bulletin No. 1962(R-1), Paragraph 3, Part II, "Repair Data", or later FAA approved revisions; or in a manner approved by the Chief, Aircraft Engineering Division, FAA Western Region. \n\t(c)\tStop drill the crack(s) in the flange with 0.25 inch hole(s) and shim in accordance with step "D", Part II, of Service Bulletins Nos. 1962(R-1) and 1962(R-1)A, and do not remove the flange. (NOTE: In this case the flange would serve as the filler.) \n\t(d)\tIf the maximum total length of the crack or the series of cracks does not exceed 6 inches in the upper and lower outboard flanges and 2 inches in the upper and lower inboard flanges: \n\t\t(1)\tStop drill any crack or cracks with a 0.25 inch hole. \n\t\t(2)\tVisually inspect cracks daily which have been stop drilled, for growth or propagation beyond the stop drill hole. If any growth is noted, additional stop drilling is required with the total crack length including propagation not to exceed the limits specified above. If a crack or cracks are found which exceed these limits, they must be repaired before further flight in accordance with paragraph (b) or (c). \n\t\t(3)\tAccomplish a permanent repair in accordance with paragraph (b) or (c) within 125 hours' time in service after crack detection. \n\t(e)\tWhen a permanent repair of cracked flanges is accomplished in accordance with paragraph (b) or (c) or if the preventive modification of uncracked flanges in Part III of Service Bulletins NOs. 1962(R-1), 1962(R-1)A, or later FAA approved revisions is accomplished, the repetitive inspections specified in paragraph (a) may be discontinued. \n\t(f)\tUpon request of an operator, an FAA maintenance inspector, subject to prior approval of the Chief, Aircraft Engineering Division, 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\t(Boeing Service Bulletins Nos. 1962(R-1) and 1962(R-1)A cover this same subject.) \n\tThis directive effective July 8, 1964.