AD 2006-20-02

You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

For airplanes identified as Groups 1 through 10 inclusive, and 17 through 36 inclusive, in Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005: Do the inspections in paragraph (f)(1) of this AD; and do the corrective action in paragraph (f)(2) of this AD as applicable. Except as provided by paragraph (i) of this AD, do all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2409, dated September 26, 1996; or Revision 5, dated August 18, 2005. After the effective date of this AD, only Revision 5 of the service bulletin may be used.

(1) At the applicable time in Figures 1, 2, 18, and 20 of Revision 5 of the service bulletin, do initial and repetitive inspections of Areas 1 and 4, as applicable, to detect disbonding, corrosion, and cracking of the skin; except any inspection using Method 1 or 2 must not be accomplished before the latest of the following, as applicable: Before the accumulation of 2,000 total flight cycles; 2,000 flight cycles since modification to the stretched upper deck (SUD) configuration; or 2,000 flight cycles since skin panel replacement in accordance with AD 90-26-10, amendment 39-6836. If inspection Method 1 or 2 is used and no disbonded doubler is found, no further action is required by this AD.

(2) If any corrosion or cracking is found during any inspection required by paragraph (f)(1) of this AD: Before further flight, except as provided by paragraph (i) of this AD, repair and do any applicable related investigative actions in accordance with the Accomplishment Instructions of Revision 5 of the service bulletin.

For airplanes identified as Groups 11 through 16 inclusive in Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005: Do the inspections in paragraph (g)(1) of this AD; and do the corrective action in paragraph (g)(2) of this AD as applicable. Except as provided by paragraph (i) of this AD, do all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005.

(1) At the applicable time in Figures 18 and 20 of the service bulletin, do initial inspections of Area 4 and repetitive inspections, as applicable, to detect disbonding, corrosion, and cracking of the skin, as applicable; except any inspection using Method 2 must not be accomplished before the latest of the following, as applicable: Before the accumulation of 2,000 total flight cycles; 2,000 flight cycles since modification to the SUD configuration; or 2,000 flight cycles since skin panel replacement in accordance with AD 90-26-10. If inspection Method 2 is used and no disbonded doubler is found, no further action is required by this AD.

(2) If any corrosion, disbonding, or cracking is found during any inspection required by paragraph (g)(1) of this AD, before further flight: Repair and do any applicable related investigative actions in accordance with the Accomplishment Instructions of the service bulletin.

For airplanes identified as Groups 1 through 10 inclusive, and 17 through 36 inclusive, in Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005: Do the inspections in paragraph (h)(1) of this AD; and do the corrective action in paragraph (h)(2) of this AD if necessary. Except as provided by paragraph (i) of this AD, do all actions in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005.

(1) At the applicable time in Figures 21 and 22 of the service bulletin: Do initial and repetitive inspections of Areas 1 and 4, as applicable, to detect cracking of the skin.

(2) If any cracking is found during any inspection required by paragraph (h)(1) of this AD, before further flight: Repair in accordance with the Accomplishment Instructions of the service bulletin.

(i) Do all actions in accordance with the applicable service bulletin except as provided by paragraphs (i)(1), (i)(2), (i)(3), (i)(4), and (i)(5) of this AD.

(1) For the action in paragraph (f)(1) of this AD: Where Boeing Alert Service Bulletin 747-53A2409, dated September 26, 1996; and Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005; specify a compliance time after the issuance of any revision of the service bulletin, this paragraph requires compliance before the specified compliance time after November 27, 1996 (the effective date of AD 96-23-02).

(2) For the actions in paragraphs (g)(1) and (h)(1) of this AD: Where Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005, specifies a compliance time after the issuance or receipt of any revision of the service bulletin, this paragraph requires compliance before the specified compliance time after the effective date of this AD.

(3) For any repair or any inspection where Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005, specifies to contact the manufacturer for further instructions: Before further flight, repair or inspect using a method approved in accordance with the procedures specified in paragraph (k) of this AD.

(4) If corrosion is found during any inspection required by this AD, before further flight: Repair in accordance with an FAA-approved method.

(5) Where Boeing Alert Service Bulletin 747-53A2409, Revision 5, dated August 18, 2005, specifies that it is not necessary to count flight cycles at 2.0 psi or less cabin differential pressure, this AD does not allow for that adjustment factor.

Actions done before the effective date of this AD in accordance with the service bulletins specified in Table 1 of this AD are acceptable for compliance with the corresponding requirements of paragraphs (f) and (g) of this AD.