Airworthiness Directive · Amendment 39-15901 · Fuselage
Boeing Model 747-400 and 747-400D Series Airplanes
Superseded. A later AD replaced this one: AD 2013-22-11. Comply with the one in force.
This AD applies to Boeing Model 747-400 and 747-400D series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2688, dated August 21, 2008.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-400 and 747-400D series airplanes. This AD requires repetitive inspections to detect cracks in the floor panel attachment fastener holes of the Section 41 upper deck floor beam upper chords, and related investigative and corrective actions if necessary. This AD results from reports of cracks found in the Section 41 upper deck floor beam upper chords. We are issuing this AD to detect and correct cracks in these chords, which could become large and cause the floor beams to become severed and result in rapid decompression or reduced controllability of the airplane.
Comply with this AD within the compliance times specified, unless already done.
Except as required by paragraphs (h) and (i) of this AD: At the applicable times in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2688, dated August 21, 2008 (“the service bulletin”), do an inspection (open-hole or surface high frequency eddy current) to detect cracks in the floor panel attachment fastener holes of the Section 41 upper deck floor beam upper chords, and do applicable related investigative and corrective actions, by accomplishing all the applicable actions specified in the Accomplishment Instructions of the service bulletin. Repeat the inspections thereafter at the applicable times specified in paragraph 1.E., “Compliance,” of the service bulletin.
(h) If any crack is found during any inspection required by paragraph (g) of this AD, and Boeing Alert Service Bulletin 747-53A2688, dated August 21, 2008, specifies to contact Boeing for appropriate action: Before further flight, repair the crack using a method approved in accordance with the procedures specified in paragraph (j) of this AD.
(i) Where Boeing Alert Service Bulletin 747-53A2688, dated August 21, 2008, specifies a compliance time after the date on the service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD.
