Airworthiness Directive · Amendment 39-14881 · Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, 747-400D, and 747SP Series Airplanes
Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, 747-400D, and 747SP Series Airplanes
This AD applies to Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, 747-400D, and 747SP series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2591, dated April 6, 2006.
The FAA is adopting a new airworthiness directive (AD) for certain Boeing Model 747-100B SUD, 747-200B, 747-300, 747-400, 747- 400D, and 747SP series airplanes. This AD requires repetitive inspections for cracking of the crease beam and adjacent intercostals, stringers, frames, and skin panels; and related investigative and corrective actions if cracking is found. This AD results from a report indicating that an operator discovered crease beam cracking on two Model 747 airplanes. We are issuing this AD to detect and correct cracking of the crease beam and adjacent structure, which could become large and result in in-flight depressurization and inability of the airframe structure to sustain flight loads.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
Perform a detailed inspection for cracking of the crease beam and adjacent intercostals, stringers, frames, and skin panels at the applicable initial and repetitive compliance times specified in Table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 747-53A2591, dated April 6, 2006; except, where the alert service bulletin specifies an initial compliance time after the date on the alert service bulletin, this AD requires compliance within the specified compliance time after the effective date of this AD. Do all applicable related investigative and corrective actions before further flight if any cracking is found. Do all applicable actions in accordance with the Accomplishment Instructions of the alert service bulletin, except as provided by paragraphs (f)(1) and (f)(2) of this AD.
(1) Where the alert service bulletin specifies to contact the manufacturer for instructions on how to repair certain conditions, before further flight, repair those conditions using a method approved in accordance with paragraph (g) of this AD.
(2) Where the alert service bulletin specifies to report certain information to the manufacturer, this AD does not include that requirement.
