Airworthiness Directive · Amendment 39-15655 · Boeing Model 747 Airplanes
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.
We are adopting a new airworthiness directive (AD) for all Boeing Model 747 airplanes. This AD requires a one-time inspection of certain fuselage skins at section 41 to find any external doublers that cover the inspection areas and to identify the external doublers that end on a stringer and those that do not, and related investigative and corrective actions if necessary. This AD results from reports of cracks found at fastener locations in the fuselage skins at section 41. We are issuing this AD to detect and correct fuselage skin cracks at fastener locations along the skin-to-stringer attachments, which could join together and become large and consequently result in rapid decompression of the cabin.
Comply with this AD within the compliance times specified, unless already done.
At the applicable compliance times specified in Tables 1 and 2 of paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007: Do a general visual inspection of the fuselage skins at section 41 to find any external doublers that cover the inspection area and to identify the external doublers that end on a stringer in the inspection area and those that do not, and do all the related investigative and corrective actions as applicable, by accomplishing all of the applicable actions specified in the Accomplishment Instructions of the service bulletin, except as provided by paragraph (g) of this AD. Repeat the related investigative actions thereafter at the interval specified in Tables 1 and 2 of the service bulletin, as applicable.
Where Tables 1 and 2 of paragraph 1.E. of Boeing Alert Service Bulletin 747-53A2704, dated October 4, 2007, specify counting the compliance time from “ * * * after the date on this service bulletin,” this AD requires counting the compliance time from the effective date of this AD. Where Figure 19 of the service bulletin specifies doing a “detailed visual inspection” for any crack at fastener holes common to the stringer, this AD requires doing a detailed inspection. In Figure 3 of the service bulletin, also inspect the areas at stringer 5 (S-5) and S-5A between station (STA) 340 and STA 360 (similar to Figure 8 for the right side). In Figure 15 of the service bulletin, also inspect the area at S-14A between STA 200 and STA 220 (similar to Figure 17 for the right side).
