E7-10982. Airworthiness Directives; Boeing Model 747-100, 747-100B, 747-100B SUD, 747-200B, 747-200C, 747-300, 747-400, 747-400D, 747SR, and 747SP Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Final rule.

SUMMARY:

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.

DATES:

This AD becomes effective July 16, 2007.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in the AD as of July 16, 2007.

On December 16, 1996 (61 FR 58318, November 14, 1996), the Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994.

ADDRESSES:

You may examine the AD docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, Washington, DC.

Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this AD.

FOR FURTHER INFORMATION CONTACT:

Patrick Gillespie, Aerospace Engineer, Cabin Safety and Environmental Systems Branch, ANM-150S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

Examining the Docket

You may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone [phone]) is located on the plaza level of the Nassif Building at the street address stated in the ADDRESSES section.

Discussion

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that supersedes AD 96-23-05, amendment 39-9810 (61 FR 58318, November 14, 1996). The existing AD applies to certain Boeing Model 747 airplanes. That NPRM was published in the Federal Register on March 15, 2007 (72 FR 12136). That NPRM proposed to continue to require 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. The NPRM also proposed to require 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.

Comments

We provided the public the opportunity to participate in the development of this AD. We have considered the single comment that has been received on the NPRM. The commenter, Boeing, supports the NPRM.

Clarification of Alternative Method of Compliance (AMOC) Paragraph

We have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies.

Conclusion

We have carefully reviewed the available data, including the comment that has been received, and determined that air safety and the public interest require adopting the AD with the change described previously. We have determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

There are about 1,012 airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs for U.S. operators to comply with this AD. The average labor rate per work hour is $80. The cost varies depending on the configuration of the airplane.

Estimated Costs

Action	Work hours	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Inspection of MEDs (required by AD 96-23-05)	Between 88 and 102	Between $7,040 and $8,160, per inspection cycle	169	Between $1,189,760 and $1,379,040, per inspection cycle.
Inspection for correct installation (new required action)	6	$480	Up to 169	Up to $81,120.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, Section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in Subtitle VII, Part A, Subpart III, Section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a substantial direct effect on the States, on the relationship between the national government and the States, or on the distribution of power and responsibilities among the various levels of government.

For the reasons discussed above, I certify that this AD:

(1) Is not a “significant regulatory action” under Executive Order 12866;

(2) Is not a “significant rule” under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and

(3) Will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act.

We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Incorporation by reference
• Safety

Adoption of the Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows:

PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

Authority: 49 U.S.C. 106(g), 40113, 44701.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by removing amendment 39-9810 ( 61 FR 58318, November 14, 1996) and by adding the following new airworthiness directive (AD):

2007-12-11 Boeing: Amendment 39-15089. Docket No. FAA-2007-27525; Directorate Identifier 2006-NM-159-AD.

Effective Date

(a) This AD becomes effective July 16, 2007.

Affected ADs

(b) This AD supersedes AD 96-23-05.

Applicability

(c) 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.

Unsafe Condition

(d) This AD results from reports that, during scheduled deployment tests of main entry door slides, corrosion was found on the floor structure supports for the escape slides of the main deck entry doors on these airplanes. This AD also 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 AD 96-23-05. 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.

Compliance

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

Restatement of Requirements of AD 96-23-05 With New Service Information

Doors Exempt From/Affected by This AD

(f) 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.

Inspections and Corrective Actions for Airplanes Equipped With Main Entry Door (MED) 1

(g) 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.

Inspections and Corrective Actions for Airplanes Equipped With MED 2, 4, and/or 5 (MED 2, 3, and/or 4 on Model 747SP Series Airplanes)

(k) 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.

Actions Accomplished According to Previous Issue of Service Bulletin

(s) 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.

New Requirements of This AD

Inspections for the Washers and Related Investigative/Corrective Actions

(t) 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.

Alternative Methods of Compliance (AMOCs)

(w)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO.

(3) AMOCs approved previously in accordance with AD 96-23-05, are approved as AMOCs for the corresponding provisions of this AD.

Material Incorporated by Reference

(x) You must use Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994; or Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005; as applicable, to perform the actions that are required by this AD, unless the AD specifies otherwise.

(1) The Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 747-53A2378, Revision 3, dated August 11, 2005, in accordance with 5 U.S.C. 552(a) and 1 CFR part 51.

(2) On December 16, 1996 (61 FR 58318, November 14, 1996), the Director of the Federal Register approved the incorporation by reference of Boeing Service Bulletin 747-53A2378, Revision 1, dated March 10, 1994.

(3) Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/​federal-register/​cfr/​ibr-locations.html.

Issued in Renton, Washington, on May 30, 2007.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.