Airworthiness Directive · Amendment 39-15089 · Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, 747SR, and 747SP Series Airplanes
Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, 747SR, and 747SP Series Airplanes
This AD applies to Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, 747SR, and 747SP series airplanes, certificated in any category, line numbers 1 through 868 inclusive.
The FAA is superseding an existing airworthiness directive (AD), which applies to certain Boeing Model 747 airplanes. That AD currently requires repetitive inspections to detect cracks and/or corrosion of the girt bar support fitting at certain main entry doors (MED), and repair or replacement of the support fitting. The existing AD also provides for various terminating actions for the repetitive inspections. This new AD requires the following additional actions: An inspection, for certain airplanes, for correct installation of square and conical washers in the girt bar support fitting; an inspection, for certain other airplanes, to determine if the washers are installed; and related investigative and corrective action if necessary. This AD results from a report that the square and conical washers may be installed incorrectly in the girt bar support fitting on airplanes on which the support fitting was repaired or replaced in accordance with the requirements of the existing AD. We are issuing this AD to detect and correct corrosion of the girt bar support fitting, which could result in separation of the escape slide from the lower door sill during deployment, and subsequently prevent proper operation of the escape slides at the main entry doors during an emergency. We are also issuing this AD to detect and correct incorrect installation of the square and conical washers in the girt bar support fitting, which could result in failure of the escape slide when deployed.
You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.
The requirements of this AD are not applicable to doors where an escape slide or slide/raft is not installed or is not used for passenger egress (such as a deactivated door 3, at doors 4 and/or 5 of an airplane being operated in the “combi” configuration, or any door not used for passenger egress in a “convertible” (an airplane configured for quick change from passenger to cargo)). The requirements of this AD are also not applicable to doors on airplanes converted to an all-cargo configuration. The requirements of this AD become applicable at the time when an escape slide or slide/raft is installed on such doors, or when such doors are activated and/or converted for passenger use. The requirements also become applicable at the time an airplane operating in an all-cargo configuration is converted to a passenger or passenger/cargo configuration.
For airplanes equipped with MED 1: Prior to the accumulation of 16 years of service since date of manufacture of the airplane, or within 18 months after December 16, 1996 (the effective date of AD 96-23-05), whichever occurs later, perform a detailed inspection to detect cracking and/or corrosion of the girt bar support fitting at the left and right MED 1, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(h) If no cracking or corrosion is found during the inspection required by paragraph (g) of this AD, prior to further flight, accomplish either paragraph (h)(1) or (h)(2) of this AD, in accordance with the applicable instructions specified in Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by paragraph (h) of this AD; or
(2) Reinstall the threshold assembly with corrosion-resistant fasteners, in accordance with the service bulletin. Thereafter, repeat the inspection required by paragraph (g) of this AD at intervals not to exceed 6 years.
(i) If any cracking is found during the inspection required by paragraph (g) or (h)(2) of this AD, prior to further flight, install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used. After these actions are accomplished, no further action is required by this paragraph.
(j) If any corrosion is found during the inspection required by paragraph (g) or (h)(2) of this AD, prior to further flight, accomplish either paragraph (j)(1) or (j)(2) of this AD, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(2) Blend out corrosion in accordance with the service bulletin.
(i) If blend out of corrosion is beyond 10 percent of original thickness or any crack is found during accomplishment of the blend out procedures, install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph.
(ii) If blend out of corrosion does not exceed 10 percent of original material thickness, accomplish either paragraph (j)(2)(ii)(A) or (j)(2)(ii)(B) of this AD:
(A) Install a new fitting with new fasteners, and reinstall threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(B) Install the repaired fitting with new fasteners and reinstall the threshold assembly with corrosion-resistant fasteners, in accordance with the service bulletin. Thereafter, repeat the inspection and applicable corrective actions required by paragraph (g) of this AD at intervals not to exceed 6 years.
For airplanes equipped with MED 2, 4, and/or 5 (MED 2, 3, and/or 4 on Model 747SP series airplanes): Prior to the accumulation of 10 years of service since date of manufacture of the airplane, or within 18 months after December 16, 1996, whichever occurs later, perform a detailed inspection to detect cracking and/or corrosion of the girt bar support fitting at the left and right MED 2, 4, and 5 (MED 2, 3, and 4 on Model 747SP series airplanes), in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(l) If no cracking or corrosion is found during the inspection required by paragraph (k) of this AD, prior to further flight, accomplish either paragraph (l)(1) or (l)(2) of this AD, in accordance with the applicable instructions in Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Remove the inspected fitting and reinstall it with a new coat of primer and new fasteners; and reinstall the threshold assembly with new corrosion-resistant fasteners; in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(2) Reinstall the serrated plate assembly and the girt bar floor fitting with corrosion-resistant fasteners, in accordance with the service bulletin. Thereafter, repeat the inspection required by paragraph (k) of this AD at intervals not to exceed 6 years.
(m) If any cracking is found during the inspection required by paragraph (k) or (l)(2) of this AD, prior to further flight, install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used. After these actions are accomplished, no further action is required by this paragraph.
(n) If any corrosion is found during the inspection required by paragraph (k) or (l)(2) of this AD, prior to further flight, accomplish either paragraph (n)(1) or (n)(2) of this AD, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747- 53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(2) Blend out corrosion in accordance with the service bulletin.
(i) If blend out of corrosion is beyond 10 percent of original thickness or any crack is found during accomplishment of the blend out procedures, install a new fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph.
(ii) If blend out of corrosion does not exceed 10 percent of original material thickness, install the repaired fitting with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph.
(o) For airplanes equipped with main entry door (MED) 3 (this paragraph does not apply to Model 747SP series airplanes): Prior to the accumulation of 16 years of service since date of manufacture of the airplane, or within 18 months after December 16, 1996, whichever occurs later, perform a detailed inspection to detect cracking and/or corrosion of the girt bar support angles at the left and right MED 3, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(p) If no cracking or corrosion is found during the inspection required by paragraph (o) of this AD, prior to further flight, accomplish either paragraph (p)(1) or (p)(2) of this AD in accordance with the applicable instructions in Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Remove the inspected angle and reinstall it with a new coat of primer and new fasteners; and reinstall the threshold assembly with new corrosion-resistant fasteners; in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(2) Reinstall the corner scuff plate and the threshold apron with corrosion-resistant fasteners, in accordance with the service bulletin. Thereafter, repeat the inspection required by paragraph (o) of this AD at intervals not to exceed 6 years.
(q) If any crack common to the support angles is found during the inspection required by paragraph (o) or (p)(2) of this AD, prior to further flight, accomplish the actions specified in paragraph (q)(1) or (q)(2), as applicable, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used:
(1) Install the new angles with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners. After these actions are accomplished, no further action is required by this paragraph of this AD; or
(2) For any cracking found only in the corner casting as specified in the service bulletin, accomplish either paragraph (q)(2)(i) or (q)(2)(ii) prior to further flight:
(i) Replace the corner casting in accordance with the service bulletin; or
(ii) Repair the cracked part in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. Refer to paragraph (w) of this AD for the appropriate procedure for seeking such an approval. (This option is provided in order to give operators time to obtain a replacement corner casing without grounding an airplane.) This repair is considered temporary action only; replacement of the corner casting eventually must be accomplished in accordance with a schedule prescribed by the Manager, Seattle ACO.
(r) If any corrosion is found during the inspection required by paragraph (o) of this AD, prior to further flight, accomplish either paragraph (r)(1) or (r)(2) of this AD, in accordance with Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005. After the effective date of this AD, only Revision 3 may be used.
(1) Install the new angles with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph; or
(2) Blend out corrosion in accordance with the service bulletin.
(i) If blend out of corrosion is beyond 10 percent of original thickness, or if any crack common to the support angles is found during accomplishment of the blend out procedures, install the new angles with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph.
(ii) If blend out of corrosion does not exceed 10 percent of original material thickness, install the repaired angles with new fasteners, and reinstall the threshold assembly with new corrosion-resistant fasteners, in accordance with the service bulletin. After these actions are accomplished, no further action is required by this paragraph.
Installation of a girt bar support fitting in accordance with Boeing Service Bulletin 747-25A2831, dated August 29, 1991, before the effective date of this AD, is considered acceptable for compliance with the corresponding requirements of paragraphs (h), (i), (j), (l), (m), and (n) of this AD for each affected fitting location.
For Groups 7, 8, and 9 airplanes identified in Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, on which the support fitting was replaced or repaired in accordance with Boeing Service Bulletin 747-53A2378, dated June 24, 1993; Revision 1, dated March 10, 1994; or Revision 2, dated July 24, 2003; or Boeing Service Bulletin 747-25A2831, dated August 29, 1991: Within 18 months after the effective date of this AD, do a general visual inspection for correct installation of square and conical washers in the girt bar floor fittings, and, before further flight, do all applicable related investigative and corrective actions. Do all actions in accordance with Figure 18 and the applicable steps specified on page 52 in the Accomplishment Instructions of Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, except as provided by paragraph (v) of this AD.
(u) For Groups 1 through 6 airplanes identified in Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, on which the support fitting was replaced or repaired in accordance with Boeing Service Bulletin 747-53A2378, dated June 24, 1993; Revision 1, dated March 10, 1994; or Revision 2, dated July 24, 2003; or with Boeing Service Bulletin 747-25A2831, dated August 29, 1991: Within 18 months after the effective date of this AD, do a general visual inspection to determine if square and conical washers are installed in the girt bar floor fittings, and before further flight, do all applicable related investigative and corrective actions. Do all actions in accordance with Figure 18 and the applicable steps specified on pages 52 and 53 in the Accomplishment Instructions of Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, except as provided by paragraph (v) of this AD.
(v) If any damage is found during any inspection required by paragraphs (t) and (u) of this AD, and Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, specifies contacting Boeing for appropriate action: Before further flight, do the repair using a method approved by the Manager, Seattle ACO, or in accordance with data meeting the certification basis of the airplane approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD.
