Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

We are superseding Airworthiness Directive (AD) 2007-26-04 for certain The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2007-26-04 required repetitive inspections for cracking of certain fasteners, and repair if necessary; and a preventive modification, which terminated the repetitive inspections. This AD removes the mandatory modification; adds repetitive inspections of the skin for cracking, a one-time inspection for defects of the production countersunk rivets, and corrective actions if necessary; and adds an optional skin trim-out repair, which will terminate certain inspections. This AD was prompted by an evaluation by the design approval holder (DAH) indicating that certain skin panels are subject to widespread fatigue damage (WFD). We are issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective July 25, 2017.

The Director of the Federal Register approved the incorporation by reference of a certain publication listed in this AD as of July 25, 2017.

ADDRESSES:

For service information identified in this final rule, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may view this referenced service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221. It is also available on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-9188.

Examining the AD Docket

You may examine the AD docket on the Internet at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-9188; or in person at the Docket Management Facility between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this AD, the regulatory evaluation, any comments received, and other information. The address for the Docket Office (phone: 800-647-5527) is Docket Management Facility, U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.

FOR FURTHER INFORMATION CONTACT:

Jennifer Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles Aircraft Certification Office (ACO), 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5264; fax: 562-627-5210; email: jennifer.tsakoumakis@faa.gov.

SUPPLEMENTARY INFORMATION:

Discussion

We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to supersede AD 2007-26-04, Amendment 39-15306 (72 FR 71216, December 17, 2007) (“AD 2007-26-04”). AD 2007-26-04 applied to certain Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on October 20, 2016 (81 FR 72554) (“the NPRM”). The NPRM was prompted by an evaluation by the DAH indicating that the forward skin panel at the station (STA) 259.5 circumferential butt splice between stringers 19L and 24L is subject to WFD. The NPRM proposed to continue to require repetitive inspections for cracking around the heads of the fasteners on the forward fastener row in certain areas of a certain circumferential butt splice, and repair if necessary. The NPRM also proposed to add repetitive inspections of the skin for cracking at the aft fastener column, and a one-time inspection for defects in the production countersunk rivets, and corrective actions if necessary; and add an optional skin trim-out repair, which would terminate certain inspections. We are issuing this AD to prevent cracking of the STA 259.5 circumferential butt splice, which could result in loss of structural integrity of the fuselage skin and possible loss of cabin pressure.

Comments

We gave the public the opportunity to participate in developing this AD. The following presents the comments received on the NPRM and the FAA's response to each comment.

Request To Revise Terminating Action

Southwest Airlines (SWA) requested that we revise paragraph (i) of the proposed AD to specify that doing the optional repairs terminates the initial and repetitive inspections instead of just the repetitive inspections. SWA stated that if a terminating repair were installed prior to the initial inspection, there is no justification for either the initial or repetitive inspections.

We agree with SWA's request. We have revised paragraph (i) of this AD to specify that the terminating repairs are applicable to both the initial and repetitive inspections.

Effect of Winglets on Accomplishment of the Proposed Actions

Aviation Partners Boeing stated that accomplishing the supplemental type certificate (STC) ST01219SE does not affect the actions specified in the NPRM.

We concur with the commenter. We have redesignated paragraph (c) of the proposed AD as paragraph (c)(1) of this AD and added paragraph (c)(2) to this AD to state that installation of STC ST01219SE does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.

Conclusion

We reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this AD with the changes described previously, and minor editorial changes. We have determined that these minor changes:

• Are consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and
• Do not add any additional burden upon the public than was already proposed in the NPRM.

We also determined that these changes will not increase the economic burden on any operator or increase the scope of this AD.

Related Service Information Under 1 CFR Part 51

We reviewed Boeing Alert Service Bulletin 737-53A1267, Revision 1, dated March 8, 2016 (“ASB 737-53A1267, R1”). The service information describes procedures for detailed inspections and high frequency eddy current (HFEC) surface inspections of the skin around the fastener heads for any crack on the forward and aft fastener columns, left and right sides, at STA 259.5 circumferential butt splice; a detailed inspection for any defect of the production countersunk rivet heads on both forward and aft fastener columns, left and right sides, at the STA 259.5 circumferential butt splice; and corrective actions, including a skin trim-out repair and other repairs. This service information is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in the ADDRESSES section.

Costs of Compliance

We estimate that this AD affects 115 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

We have received no definitive data that would enable us to provide cost estimates for the optional skin-trim-out repair specified in this AD.

We have received no definitive data that would enable us to provide cost estimates for the on-condition actions specified in this AD.

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),

(3) Will not affect intrastate aviation in Alaska, and

(4) 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.

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.

2. The FAA amends § 39.13 by removing Airworthiness Directive (AD) 2007-26-04, Amendment 39-15806 ( 72 FR 71216, December 17, 2007), and adding the following new AD:

2017-12-05 The Boeing Company: Amendment 39-18920; Docket No. FAA-2016-9188; Directorate Identifier 2016-NM-102-AD.

(a) Effective Date

This AD is effective July 25, 2017.

(b) Affected ADs

This AD replaces AD 2007-26-04, Amendment 39-15306 (72 FR 71216, December 17, 2007) (“AD 2007-26-04”).

(c) Applicability

(1) This AD applies to The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category, as identified in Boeing Alert Service Bulletin 737-53A1267, Revision 1, dated March 8, 2016 (“ASB 737-53A1267, R1”).

(2) Installation of Supplemental Type Certificate (STC) ST01219SE ( http://rgl.faa.gov/Regulatory_and_Guidance_Library/rgstc.nsf/0/ebd1cec7b301293e86257cb30045557a/$FILE/ST01219SE.pdf ) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01219SE is installed, a “change in product” alternative method of compliance (AMOC) approval request is not necessary to comply with the requirements of 14 CFR 39.17.

(d) Subject

Air Transport Association (ATA) of America Code 53, Fuselage.

(e) Unsafe Condition

This AD was prompted by an evaluation by the design approval holder indicating that the forward skin panel at the station (STA) 259.5 circumferential butt splice between stringers 19L and 24L is subject to widespread fatigue damage. We are issuing this AD to prevent cracking of the STA 259.5 circumferential butt splice, which could result in loss of structural integrity of the fuselage skin and possible loss of cabin pressure.

(f) Compliance

Comply with this AD within the compliance times specified, unless already done.

(g) Actions for Group 2 Airplanes

For airplanes identified as Group 2 in ASB 737-53A1267, R1: Within 120 days after the effective date of this AD, inspect the airplane and do all applicable corrective actions using a method approved in accordance with the procedures specified in paragraph (k) of this AD.

(h) Inspections for Group 1 Airplanes

For airplanes identified as Group 1 in ASB 737-53A1267, R1: Except as specified in paragraph (j)(1) of this AD, at the applicable time specified in paragraph 1.E. “Compliance” of ASB 737-53A1267, R1, do the applicable actions specified in paragraphs (h)(1) and (h)(2) of this AD; and do all applicable corrective actions; in accordance with the Accomplishment Instructions of ASB 737-53A1267, R1, except as specified in paragraph (j)(2) of this AD and as provided by paragraph (i) of this AD. Do all applicable corrective actions before further flight. Repeat the applicable inspections specified in paragraph (h)(1) of this AD thereafter at the applicable intervals specified paragraph 1.E., “Compliance,” of ASB 737-53A1267, R1, except as provided by paragraph (i) of this AD.

(1) Do detailed inspections and high frequency eddy current (HFEC) surface inspections of the skin around the fastener heads for any crack on the forward and aft fastener columns, left and right sides, at STA 259.5 circumferential butt splice, in accordance with Parts 1, 2, 6, 7, 8, and 9 of the Accomplishment Instructions of ASB 737-53A1267, R1, as applicable.

(2) Do a one-time detailed inspection for any defect of the production countersunk rivet heads on both forward and aft fastener columns, left and right sides, at STA 259.5 circumferential butt splice, in accordance with Part 3 of the Accomplishment Instructions of ASB 737-53A1267, R1.

(i) Repairs That Terminate Inspections in Repair Areas

(1) For airplanes identified as Group 1, Configuration 1, in ASB 737-53A1267, R1: Doing the skin trim-out repair specified in Part 5 of the Accomplishment Instructions of ASB 737-53A1267, R1, terminates the initial and repetitive inspections required by paragraph (h) of this AD that are specified in Part 1 of the Accomplishment Instructions of ASB 737-53A1267, R1, only; all other inspections required by paragraph (h) of this AD must be done, except as provided by paragraph (i)(2) of this AD.

(2) For airplanes identified as Group 1, Configuration 1 in ASB 737-53A1267, R1: Doing the skin repair specified in Part 4 of the Accomplishment Instructions of ASB 737-53A1267, R1, terminates the initial and repetitive inspections required by paragraph (h) of this AD that are specified in Part 1 and Part 2 of the Accomplishment Instructions of ASB 737-53A1267, R1, for the repaired area only; all other inspections required by paragraph (h) of this AD must be done, except as provided by paragraph (i)(1) of this AD.

(j) Exceptions to Service Information

(1) Where paragraph 1.E., “Compliance,” of ASB 737-53A1267, R1, specifies a compliance time “after the Revision 1 date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.

(2) Although ASB 737-53A1267, R1, specifies to contact Boeing for appropriate action, and specifies that action as “RC” (Required for Compliance), this AD requires repair before further flight using a method approved in accordance with the procedures specified in paragraph (k) of this AD.

(k) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Los Angeles Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. In accordance with 14 CFR 39.19, send your request to your principal inspector or local Flight Standards District Office, as appropriate. If sending information directly to the manager of the ACO, send it to the attention of the person identified in paragraph (l) of this AD. Information may be emailed to: 9-ANM-LAACO-ACO-AMOC-Requests@faa.gov.

(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the local flight standards district office/certificate holding district office.

(3) An AMOC that provides an acceptable level of safety may be used for any repair, modification, or alteration required by this AD if it is approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) that has been authorized by the Manager, Los Angeles ACO, to make those findings. To be approved, the repair method, modification deviation, or alteration deviation must meet the certification basis of the airplane and the approval must specifically refer to this AD.

(4) AMOCs approved previously for AD 2007-26-04 are approved as AMOCs for the corresponding provisions of this AD.

(5) Except as required by paragraph (j)(2) of this AD: For service information that contains steps that are labeled as RC, the provisions of paragraphs (k)(5)(i) and (k)(5)(ii) of this AD apply.

(i) The steps labeled as RC, including substeps under an RC step and any figures identified in an RC step, must be done to comply with the AD. If a step or substep is labeled “RC Exempt,” then the RC requirement is removed from that step or substep. An AMOC is required for any deviations to RC steps, including substeps and identified figures.

(ii) Steps not labeled as RC may be deviated from using accepted methods in accordance with the operator's maintenance or inspection program without obtaining approval of an AMOC, provided the RC steps, including substeps and identified figures, can still be done as specified, and the airplane can be put back in an airworthy condition.

(l) Related Information

For more information about this AD, contact Jennifer Tsakoumakis, Aerospace Engineer, Airframe Branch, ANM-120L, FAA, Los Angeles ACO, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5264; fax: 562-627-5210; email: jennifer.tsakoumakis@faa.gov.

(m) Material Incorporated by Reference

(1) The Director of the Federal Register approved the incorporation by reference (IBR) of the service information listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51.

(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise.

(i) Boeing Alert Service Bulletin 737-53A1267, Revision 1, dated March 8, 2016.

(ii) Reserved.

(3) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740-5600; telephone 562-797-1717; Internet https://www.myboeingfleet.com.

(4) You may view this service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.

(5) You may view this service information that is incorporated by reference 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.