74-19-07 BOEING: Amendment 39-1961. Applies to Boeing Model 747 Series aircraft certificated in all categories with more than 2,000 flights. Compliance required as noted: \n\n\t(A)\tWithin the next 100 flights, determine the thickness of the flap control handle detent pin in accordance with FAA approved Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA Northwest Region. Flap control handle detent pins with more than .110 inch thickness remaining are to be inspected at intervals not to exceed 2,000 flights. Pins with .110 or less but more than .070 inch thickness are to be inspected at intervals not to exceed 750 flights. Pins with .070 or less but more than .050 inch thickness remaining are to be inspected at intervals not to exceed 250 flights. Pins with .050 or less but more than .045 inch thickness must be replaced within 100 flights. Pins with .045inch or less thickness remaining are to be replaced with an approved flap control handle prior to further flight. \n\t(B)\tOn or before September 1, 1975, relocate the bias spring in accordance with FAA approved Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region. \n\t(C)\tRework of the flap control handle detent pin, refinish of the detent plate and relocation of the bias spring, in accordance with Boeing Service Bulletin 747-27-2121, Revision 1, dated June 14, 1974, or later FAA approved revisions, or in a manner approved by the Chief, Engineering and Manufacturing Branch, FAA, Northwest Region, constitutes terminating action under the provisions of this AD. \n\t(D)\tUpon request of the operator, an FAA maintenance inspector, subject to prior approval of the Chief, Engineering and Manufacturing Branch, FAA, Northwest 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 adjustment period. \n\n\tThis amendment becomes effective 30 days after September 20, 1974.