Document ID: chunk:federal_register_of_legislation:F2007L02145:body:0:p5
Version: federal_register_of_legislation:F2007L02145
Segment Type: other
Provision Reference: 
Character Range: 12232–15126

of the body frame and adjacent skin between BS 420 and 460 inclusive and between stringers S-8 and S-12 inclusive, in accordance with Figure 17 of the Accomplishment Instructions of Boeing service bulletin BSB 747-53A2265 Revision 9.
Compliance:     1. Before the accumulation of 8,000 total flight cycles, or within 10 flight cycles after receipt of this Directive, whichever occurs later.  Inspect thereafter at intervals not to exceed 25 flight cycles.

                2. Inspect in accordance with Requirement 2 at the times specified in the requirements section, paragraphs 2A to 2E as applicable.

             Modification in accordance with Boeing SB 747-53-2272, Revision 18 cancels the inspections per Requirements 1 and 2, together with Requirements 5 through Requirement 9 (inclusive) of this Directive for the modified areas only.

             The internal inspections behind the Flight Engineer's panel (BS 340 to 390, from stringer 1R to 10AR) may, on Group 1, 2 and 3 aircraft, be deferred until 13,000 flights, provided that no critical element of the pressure shell structure within the corresponding location on the left hand side is severed or otherwise locally ineffective, or has been previously replaced or repaired due to fatigue damage.

             Where internal inspections have been deferred, external skin inspections must be conducted in accordance with Boeing NDT Manual D6-7170, Part 6 Subject 53-30-00 Figure 2 at intervals not to exceed 1000 flight cycles.

             Note 13:  For the purposes of this deferment, critical elements of the pressure shell structure shall include any frame, tear strap, skin or splice doubler, but may exclude the surrounding structure of the crew escape hatch (BS 340 to 380, S-1 to 3).

   Note 14:  If failed structure has been found on the left hand side, an exemption may still be available from the Authority, (deferring the close detailed internal inspection on the right side for an interval of 1500 flights but not beyond 13,000 flights total), if it can clearly be shown, using alternative methods, that there is no major cracking of the corresponding element on the right hand side.

      3. Inspect in accordance with Requirement 3 before further flight after any frame cracks are found forward of BS 520.

      4. Inspect in accordance with Requirement 4 before further flight after discovery of cracks longer than 25mm in any frame or floor beam, forward of BS 520.

   Note 15:  Aircraft known to have unrepaired cracks shall not be returned to service without the prior approval of the Authority.

   Note 16:  For the purposes of this AD, flights on which the cabin pressure differential does not exceed 2.0 psi need not be counted.

        5. (a) For Group 1 through 6 airplanes: accomplish before the accumulation of 8,000 total flight cycles, or within 2,000 flight cycles after the