AD 2008-16-14

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 having line numbers 201 through 765 inclusive: Conduct an HFEC inspection to detect cracking of the lower lobe lap joints in the vicinity of the wing-to-body fairings, in accordance with Boeing Alert Service Bulletin 747-53A2312, dated June 12, 1989; Revision 1, dated March 29, 1990; Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD; at the time specified in paragraph (f)(1), (f)(2), (f)(3), or (f)(4) of this AD, as applicable. As of the effective date of this AD, only Revision 3 shall be used. Repeat this inspection thereafter at intervals not to exceed 4,000 landings until the inspection required by paragraph (j) of this AD is accomplished.

(1) For airplanes that have accumulated less than 11,200 total landings as of February 5, 1990 (the effective date of AD 90-01-07, amendment 39-6440, which was superseded by AD 94-15-06): Prior to the accumulation of 11,000 total landings, or within the next 1,000 landings after February 5, 1990, whichever occurs later.

(2) For airplanes that have accumulated 11,200 or more total landings but less than 15,201 total landings as of February 5, 1990: Within the next 1,000 landings after February 5, 1990, or prior to the accumulation of 15,500 total landings, whichever occurs earlier.

(3) For airplanes that have accumulated 15,201 or more total landings but less than 18,200 total landings as of February 5, 1990: Within the next 300 landings after February 5, 1990, or prior to the accumulation of 18,250 total landings, whichever occurs earlier.

(4) For airplanes that have accumulated 18,200 or more landings as of February 5, 1990: Within the next 50 landings after February 5, 1990.

For airplanes having line numbers 201 through 765 inclusive: Accomplish the requirements of paragraphs (g)(1) and (g)(2) of this AD.

(1) If any cracking is detected during the inspections required by paragraph (f) of this AD, prior to further flight, repair in accordance with Boeing Alert Service Bulletin 747-53A2312, dated June 12, 1989; Revision 1, dated March 29, 1990; Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used.

(2) Prior to the accumulation of 20,000 total landings, or within the next 3,000 landings after February 5, 1990 (the effective date of AD 90-01-07), whichever occurs later, modify the airplane by replacing countersunk fasteners in the upper row of the lower lobe lap joints in the vicinity of the wing-to-body fairings with protruding head fasteners, in accordance with the procedures described in Boeing Alert Service Bulletin 747-53A2312, dated June 12, 1989; Revision 1, dated March 29, 1990; Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used.

For airplanes having line numbers 201 through 765 inclusive: Before the effective date of this AD, for purposes of complying with paragraphs (f) and (g) of this AD, the number of landings may be determined to equal the number of pressurization cycles where the cabin pressure differential was greater than 2.0 psi.

(i) For airplanes having line numbers 201 through 765 inclusive: Before the effective date of this AD, for Model 747SR series airplanes only, based on continued mixed operation of lower cabin differentials, the inspection and modification compliance times specified in paragraphs (f) and (g) of this AD may be multiplied by a 1.2 adjustment factor.

For all airplanes: Prior to the accumulation of 11,000 total landings, or within 1,000 landings after August 24, 1994 (the effective date of AD 94-15-06), whichever occurs later, conduct a general visual inspection, unless previously accomplished within the last 3,000 landings prior to August 24, 1994, to determine if countersunk fasteners have been installed in the lap joints listed in paragraph (j)(1) or (j)(2) of this AD, as applicable, in accordance with the procedures described in Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used. Accomplishment of this inspection terminates the inspection requirements of paragraph (f) of this AD.

(1) For Model 747-100, -200, -300, -400, and 747SR series airplanes: From body stations (BS) 741 to 1000 at stringers (S)-34L, S-34R, S-39L, S-39R, S-44L, and S-44R, and from BS 1480 to 1741 at S-34L, S-34R, S-40L, and S-40R.

(2) For Model 747SP series airplanes: From BS 560 to 800 at S-34L, S-34R, S-39L, S-39R, S-44L, and S-44R, and from BS 1640 to 1741 at S-34L, S-34R, S-40L, and S-40R.

For all airplanes: If no countersunk fastener is found in the upper row of a lap joint during the inspection required by paragraph (j) of this AD, no further action is required by this AD for that lap joint.

(l) For all airplanes: If any countersunk fastener is found in the upper row of a lap joint during the inspection required by paragraph (j) of this AD, prior to further flight, perform an HFEC inspection to detect cracking at all fastener locations in the lap joint where a countersunk fastener was found during the inspection required by paragraph (j) of this AD, in accordance with the procedures described in Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used.

If no cracking is detected during any inspection required by paragraphs (l) and (q) of this AD, at any fastener location where a countersunk fastener was found during the inspection required by paragraph (j) or (q)(1) of this AD, repeat the HFEC inspection thereafter at intervals not to exceed 4,000 landings, in accordance with the procedures described in Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used. As an alternative to the HFEC inspection, operators may perform a detailed inspection to detect cracking at any fastener location where a countersunk fastener was found, in accordance with the procedures described in Boeing Service Alert Bulletin 747-53A2312, Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. Perform the detailed inspection within the next 4,000 landings after the HFEC inspection required by paragraph (l) of this AD, and repeat the inspection thereafter at intervals not to exceed 500 landings. At any of the subsequent inspection cycles, operators may use either inspection method provided that the corresponding inspection interval is used to determine the compliance time of the next inspection.

(n) If cracking is detected during any inspection required by paragraph (l), (m), (p), or (q) of this AD, at any fastener location where a countersunk fastener was found during the inspection required by paragraph (j) or (q)(1) of this AD, prior to further flight, repair and modify that lap joint in accordance with Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used. Accomplishment of this repair and modification terminates the repetitive inspections required by paragraph (m) of this AD for that lap joint.

For all airplanes: Prior to the accumulation of 20,000 total landings or within 1,000 landings after August 24, 1994, whichever occurs later, modify all fastener locations where a countersunk fastener was found during the inspections required by paragraph (j) of this AD, in accordance with the procedures described in Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used. For purposes of complying with the requirements of this paragraph, fastener locations that were previously modified in accordance with paragraph (g) or (n) of this AD do not need to be modified again. Accomplishment of this modification terminates the repetitive inspections required by paragraph (m) of this AD for the modified fastener locations.

For all airplanes: Prior to the accumulation of 10,000 total landings following the modification required by paragraph (g), (n), (o), (q) or (s) of this AD, perform an HFEC inspection to detect cracking at all fastener locations where a countersunk fastener was found during the inspection required by paragraph (j) or (q)(1) of this AD, and repeat this inspection thereafter at intervals not to exceed 4,000 landings, in accordance with the procedures described in Boeing Service Bulletin 747-53A2312, Revision 2, dated October 8, 1992; or Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. As of the effective date of this AD, only Revision 3 shall be used.

For Model 747SP series airplanes having line numbers 201 through 814 inclusive, do the actions in paragraphs (q)(1) and (q)(2) of this AD at the times specified in those paragraphs.

(1) Prior to the accumulation of 11,000 total landings, or within 1,000 landings as of the effective date of this AD, whichever occurs later, unless previously accomplished within the last 3,000 landings prior to the effective date of this AD, conduct a general visual inspection of the lap joint from BS 1640 to 1901 at S-46L, and from BS 1741 to 1901 at S-34L, S-34R, S-40L, and S-40R, to determine if countersunk fasteners have been installed in the specified area, in accordance with the procedures described in Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD.

(i) If no countersunk fastener is found in the upper row of the lap joint during the inspection, no further action is required by this AD for the lap joint.

(ii) If any countersunk fastener is found in the upper row of the lap joint, prior to further flight, perform an HFEC inspection to detect cracking at all fastener locations where a countersunk fastener was found, in accordance with the procedures described in Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD.

(A) If no cracking is found, repeat the inspection thereafter in accordance with the requirements of paragraph (m) of this AD.

(B) If any cracking is found, prior to further flight, repair and modify the lap joint as required by paragraph (n) of this AD.

(2) Prior to the accumulation of 20,000 total landings, or within 1,000 landings as of the effective date of this AD, whichever occurs later, modify all fastener locations where a countersunk fastener was found, during the inspection required by paragraph (q)(1) of this AD, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. For purposes of complying with the requirements of this AD, fastener locations that were previously modified in accordance with paragraph (n) of this AD do not need to be modified again. Accomplishment of this modification terminates the repetitive inspections required by paragraph (m) of this AD for the modified fastener locations.

For the purposes of calculating the compliance threshold and repetitive intervals for actions required by paragraphs (f) and (g) of this AD, as of the effective date of this AD: All flight cycles, including the number of flight cycles in which cabin differential pressure is at 2.0 psi or less, must be counted when determining the number of flight cycles that have occurred on the airplane, and a 1.2 adjustment factor may not be used. However, for airplanes on which the repetitive intervals for the actions required by paragraph (f) of this AD have been calculated in accordance with paragraphs (h) and/or (i) of this AD by excluding the number of flight cycles in which cabin differential pressure is at 2.0 pounds psi or less, and/or by using a 1.2 adjustment factor: Continue to adjust the repetitive intervals in accordance with paragraphs (h) and/or (i) of this AD until the next inspection required by paragraph (f) of this AD is accomplished. Thereafter, no adjustment to compliance times based on paragraphs (h) and/or (i) of this AD is allowed.

For airplanes with line numbers 630 through 814 inclusive that meet the conditions specified in paragraphs (s)(1) and (s)(2) of this AD: Within 300 flight cycles after the effective date of this AD, or within 500 flight cycles after the most recent sliding probe inspection done in accordance with Boeing Alert Service Bulletin 747-53A2312, Revision 1, dated March 29, 1990; or Revision 2, dated October 8, 1992; whichever occurs later, do a special one-time HFEC inspection or a special one-time detailed inspection for cracking, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007. If any cracking is found in a lap joint, before further flight, repair and modify that lap joint in accordance with Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007; except as provided by paragraph (u) of this AD. Accomplishment of this repair and modification terminates the repetitive inspections required by paragraph (m) of this AD for that lap joint. This special one-time inspection is not required for lap joints that have been modified in accordance with paragraph (g), (n), (o), or (q) of this AD.

(1) Airplanes that have not been modified in accordance with paragraph (g) or (o) of this AD.

(2) Airplanes on which the sliding probe HFEC inspection method specified in Boeing Alert Service Bulletin 747-53A2312, Revision 1, dated March 29, 1990; or Revision 2, dated October 8, 1992; was used during the last skin inspection required by paragraph (f), (l), or (m) of this AD.

For airplanes specified in paragraph (s) of this AD on which no cracking is found during the special one-time inspection, do the applicable repetitive inspections specified in paragraph (t)(1) or (t)(2) of this AD.

(1) If the special one-time inspection was done using the HFEC inspection method in accordance with paragraph (s) of this AD, perform the next inspection required by paragraph (m) of this AD within the next 4,000 flight cycles after doing the inspection required by paragraph (s) of this AD, and repeat the inspection thereafter in accordance with paragraph (m) of this AD.

(2) If the special one-time inspection was done using the detailed inspection method in accordance with paragraph (s) of this AD, perform the next inspection required by paragraph (m) of this AD within the next 500 flight cycles after doing the inspection required by paragraph (s) of this AD, and repeat the inspection thereafter in accordance with paragraph (m) of this AD.

Where Boeing Alert Service Bulletin 747-53A2312, Revision 3, dated February 8, 2007, specifies to contact Boeing for appropriate action for a repair or inspection, before further flight, do the applicable action in paragraph (u)(1) or (u)(2) of this AD.

(1) Do the repair using a method approved in accordance with the procedures specified in paragraph (v) of this AD.

(2) Do the inspection using a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. For a repair method to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically refer to this AD.