Airworthiness Directive · Amendment 39-15931 · Fuselage
Boeing Model 747 Airplanes
This AD applies to all Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-200F, 747-300, 747-400, 747-400D, 747-400F, 747SR, and 747SP series airplanes, certificated in any category.
The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This AD requires inspecting for cracks in the left- and right-side Stringer 11 longeron adjacent to the horizontal stabilizer pivot bulkhead, and related investigative and corrective actions if necessary. This AD results from a report of a crack found in the right-side Stringer 11 longeron horizontal flange, adjacent to the horizontal stabilizer pivot bulkhead, during a routine maintenance inspection. We are issuing this AD to detect and correct fatigue cracking of the longeron, which can propagate and cause damage to the adjacent horizontal stabilizer pivot bulkhead. This damage could result in loss of structural integrity and consequent inability of the bulkhead to carry flight loads, which could adversely affect controllability of the airplane.
Comply with this AD within the compliance times specified, unless already done.
Except as provided by paragraph (h) of this AD: At the applicable times specified in paragraph 1.E. of Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, do a surface high frequency eddy current (HFEC) inspection for cracks in the left- and right-side Stringer 11 longeron exposed surfaces and edges between Station 2598 and 2607 adjacent to the horizontal stabilizer pivot bulkhead; and do all applicable related investigative and corrective actions before further flight, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, except as provided by paragraph (i) of this AD.
Where Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, specifies counting the compliance time from “ * * * the date on this service bulletin,” this AD requires counting the compliance time from the effective date of this AD.
(i) If any crack is found during any inspection required by this AD, and Boeing Service Bulletin 747-53A2703, Revision 1, dated September 16, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (k) of this AD.
Inspections, related investigative actions, and corrective actions accomplished before the effective date of this AD according to Boeing Alert Service Bulletin 747-53A2703, dated February 14, 2008, are considered acceptable for compliance with the corresponding actions specified in paragraph (g) of this AD.
