Airworthiness Directive · Amendment 39-15522 · Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP Series Airplanes
Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP Series Airplanes
Superseded. A later AD replaced this one: AD 2009-04-16, AD 2010-10-05. Comply with the one in force.
This AD applies to Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes, certificated in any category; as identified in Boeing Alert Service Bulletin 747-53A2748, dated May 9, 2008.
We are adopting a new airworthiness directive (AD) for certain Boeing Model 747-100, 747-100B, 747-200B, 747-200C, 747-200F, 747-300, 747SR, and 747SP series airplanes. This AD requires an inspection to determine if acceptable external skin doublers are installed at the stringer 6 (S-6) lap splices, between station (STA) 340 and STA 400. For airplanes without the acceptable external skin doublers, this AD requires repetitive related investigative actions and corrective actions if necessary. This AD also provides an optional terminating modification for the repetitive related investigative actions. This AD results from a report of cracked fastener holes at the right S-6 lap splice between STA 340 and STA 380. We are issuing this AD to detect and correct cracking in the fuselage skin, which could result in rapid decompression and loss of structural integrity.
Comply with this AD within the compliance times specified, unless already done.
The term “alert service bulletin,” as used in this AD, means the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2748, dated May 9, 2008.
For airplanes identified as Group 1, Configuration 2, in Boeing Alert Service Bulletin 747-53A2748, dated May 9, 2008: At the latest of the times specified in paragraphs (g)(1), (g)(2), and (g)(3) of this AD, do an external general visual inspection to determine if acceptable external skin doublers are installed at the left- and right-side S-6 lap splices, in accordance with Part 1 of the alert service bulletin.
(1) Prior to the accumulation of 10,000 total flight cycles.
(2) Within 8,000 flight cycles after a modification was done in accordance with Boeing Service Bulletin 747-53-2253.
(3) Within 15 days or 100 flight cycles after the effective date of this AD, whichever occurs first.
If, during the inspection required by paragraph (g) of this AD, acceptable external skin doublers in accordance with the alert service bulletin are found installed at both the left- and right-side S-6 lap splices, no further work is required by this AD.
(i) If, during the inspection required by paragraph (g) of this AD, acceptable external skin doublers in accordance with alert service bulletin are not found installed at either the left- or right-side S-6 lap splice: Before further flight, do all applicable related investigative and corrective actions by doing all actions specified in Part 2 of the alert service bulletin. Repeat the applicable related investigative actions thereafter at intervals not to exceed 300 flight cycles until the modification specified in paragraph (j) of this AD is done.
Modifying the airplane by installing acceptable external skin doublers at both the left- and right-side S-6 lap splices (including doing an open-hole HFEC inspection of the skin for cracking, and trimming out cracking as applicable) in accordance with the alert service bulletin terminates the repetitive related investigative actions required by this AD.
Note 1: The alert service bulletin refers to Boeing Service Bulletins 747-53-2253, Revision 3, dated March 24, 1994; and 747-53-2272, Revision 18, dated May 16, 2002; as additional sources of service information for accomplishment of the modification (installation of acceptable external skin doublers).
Note 2: AD 90-06-06, amendment 39-6490, requires, among other actions, one of the modification options specified in Boeing Service Bulletin 747-53-2253, dated December 14, 1984.
Note 3: AD 90-23-14, amendment 39-6801, requires that inspections of modifications done in accordance with Boeing Service Bulletin 747-53-2253, and applicable repairs, be done in accordance with Boeing Service Bulletin 747-53-2253, Revision 2, dated March 29, 1990.
