Airworthiness Directive · Amendment 39-16111 · Fuselage
Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, and 747SR Series Airplanes
This AD applies to Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, and 747SR series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2751, dated October 9, 2008.
We are issuing a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, and 747SR series airplanes. This AD requires a one-time general visual inspection for missing fasteners in certain stringer-to-stringer clip joints at the station (STA) 760 through STA 940 frames, and related investigative and corrective actions if necessary. This AD results from a report of broken and cracked frame shear ties, cracks on the frame doubler and frame web, and missing fasteners in the stringer (S) -10L stringer-to- stringer clip joint at the STA 820 frame. We are issuing this AD to detect and correct missing fasteners in the stringer-to-stringer clip joints, which could result in shear tie and skin cracks and rapid in- flight decompression of the airplane.
Comply with this AD within the compliance times specified, unless already done.
Within 3,000 flight cycles after the effective date of this AD: Do a one-time general visual inspection for missing fasteners in the left and right side S-10, S-10A, and S-11 stringer-to-stringer clip joints at the STA 760 through 940 frames, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2751, dated October 9, 2008. If any fasteners are missing, before further flight, do detailed and surface high frequency eddy current inspections to detect cracking of the adjacent frame and skin structure in accordance with the Accomplishment Instructions of the service bulletin. Install all missing fasteners before further flight.
(h) If any crack is found during the inspection required by paragraph (g) of this AD: Before further flight, repair any cracked shear ties, frame web, and/or skin in accordance with Boeing Alert Service Bulletin 747-53A2751, dated October 9, 2008.
(i) If any repair is done in accordance with paragraph (h) of this AD, before 20,000 total flight cycles or within 3,000 flight cycles from the repair installation, whichever occurs later: Do a detailed inspection of the repair(s) and the adjacent structure within 10 inches of the repair(s) for cracking. Repeat the inspection thereafter at intervals not to exceed 3,000 flight cycles. If any crack is found during this inspection, before further flight, repair using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
