Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Supplemental notice of proposed rulemaking (SNPRM); reopening of comment period.

SUMMARY:

We are revising an earlier notice of proposed rulemaking (NPRM) to supersede Airworthiness Directive (AD) 2014-12-13, which applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. This action revises the NPRM by expanding the inspection area. This action also revises the NPRM by no longer proposing to supersede AD 2014-12-13. We are proposing this AD to address the unsafe condition on these products. Since these actions impose an additional burden over that proposed in the NPRM, we are reopening the comment period to allow the public the chance to comment on these proposed changes.

DATES:

The comment period for the NPRM published in the Federal Register on January 5, 2017 (82 FR 1254), is reopened.

We must receive comments on this SNPRM by September 5, 2017.

ADDRESSES:

You may send comments, using the procedures found in 14 CFR 11.43 and 11.45, by any of the following methods:

• Federal eRulemaking Portal: Go to http://www.regulations.gov. Follow the instructions for submitting comments.
• Fax: 202-493-2251.
• Mail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue SE., Washington, DC 20590.
• Hand Delivery: Deliver to Mail address above between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

For service information identified in this SNPRM, contact Boeing Commercial Airplanes, Attention: Contractual & Data Services (C&DS), 2600 Westminster Blvd., MC 110-SK57, Seal Beach, CA 90740; telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may view this referenced service information at the FAA, Transport Standards Branch, 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-2016-9523.

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-2016-9523; 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 SNPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Office (phone: 800-647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.

FOR FURTHER INFORMATION CONTACT:

Payman Soltani, Aerospace Engineer, Airframe Section, FAA, Los Angeles Aircraft Certification Office (ACO) Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5313; fax: 562-627-5210; email: payman.soltani@faa.gov.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to send any written relevant data, views, or arguments about this proposed AD. Send your comments to an address listed under the ADDRESSES section. Include “Docket No. FAA-2016-9523; Product Identifier 2016-NM-134-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this SNPRM. We will consider all comments received by the closing date and may amend this SNPRM because of those comments.

We will post all comments we receive, without change, to http://www.regulations.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this proposed AD.

Discussion

On June 6, 2014, we issued AD 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014) (“AD 2014-12-13”). AD 2014-12-13 requires actions to address an unsafe condition on all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. AD 2014-12-13 requires repetitive inspections for cracking of the aft support fitting for the main landing gear (MLG) beam, and the rear spar upper chord and rear spar web; and repair if necessary.

We issued an NPRM to amend 14 CFR part 39 by adding an AD to supersede AD 2014-12-13 that would apply to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. The NPRM published in the Federal Register on January 5, 2017 (82 FR 1254) (“the NPRM”). The NPRM was prompted by reports of additional cracking in the inspar upper skin at Wing Buttock Line (WBL) 157 and in the skin at two holes common to the rear spar in the same area, and by reports of rear spar web cracks on both wings. Subsequent inspections revealed that the right rear spar upper chord was almost completely severed and the left rear spar upper chord was completely severed. The NPRM proposed to expand the inspection area and add applicable related investigative and corrective actions.

Actions Since NPRM Was Issued

Since we issued the NPRM, we have determined it is necessary to expand the inspection area because the NPRM did not adequately identify the inspection area. We have also determined that it is necessary for operators to do the inspections in this proposed AD (in the SNPRM) before the inspections in AD 2014-12-13 can be terminated. In the NPRM, we proposed to supersede AD 2014-12-13 and referred to the compliance times in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, which would have given operators an additional 4,500 flight cycles to do the next inspection. However, operators must do the inspections at the compliance times required by AD 2014-12-13 until the actions required by this proposed AD (in the SNPRM) are done. Therefore, we are no longer superseding AD 2014-12-13. However, we have included paragraph (k)(2) in this proposed AD (in the SNPRM) to specify terminating action for AD 2014-12-13.

Related Service Information Under 1 CFR Part 51

We reviewed Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016. The service information describes procedures for repetitive high frequency eddy current (HFEC) open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web at the 12 fastener holes (locations 1-12). The service information also describes procedures for optional HFEC open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web, and HFEC surface inspections for any cracking in the rear spar upper chord and rear spar upper web, as applicable. The service information also describes procedures for related investigative and corrective actions.

We also reviewed Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016. The service information describes procedures for repetitive eddy current inspections of the left and right wing for any cracking in the inspar upper skin and at the repair parts if applicable, and related investigative and corrective actions.

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.

Comments

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

Request To Include Other Inspection Areas

Boeing requested that the NPRM be revised to include other inspection areas during the HFEC open hole inspection. Boeing stated that, as written, the NPRM implies that in some options the upper chord and web do not need to be inspected during the HFEC open hole inspection.

We agree with the commenter's request for the reasons stated above. We have revised the introductory text to paragraph (h) of this proposed AD (in the SNPRM) to include an HFEC inspection of the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web.

Request To Revise the NPRM or Service Information To Allow Installation of the Same Type and Size of Fasteners

All Nippon Airlines (ANA) requested that paragraph (h) of the NPRM or the service information be revised to allow installation of the same type and size of fasteners previously removed from the airplane after the open hole HFEC inspection. ANA stated that for group 7 airplanes, figures 25 and 26 of Boeing Alert Service Bulletin 737-57A1318, May 15, 2013, specify that oversized fasteners are installed at fastener holes after the open hole HFEC inspection has been accomplished. ANA stated that, however, for the same group 7 airplanes, figures 29 and 30 of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, specify that standard size fasteners are installed at fastener holes after the open hole HFEC inspection has been accomplished. ANA stated that as a result, operators will have to request alternative methods of compliance (AMOCs) for all airplanes on which the actions in Boeing Alert Service Bulletin 737-57A1318, May 15, 2013, have already been done because paragraph (h) of the NPRM states to do all applicable related investigative and corrective actions using Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, which includes the installation of the standard size fasteners. ANA stated that this would be a burden for operators, Boeing, and the FAA.

We agree with the commenter's request to revise this proposed AD. Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, should have called out the correct fastener size to be installed after the fastener holes have been inspected and oversized as specified in Boeing Alert Service Bulletin 737-57A1318, May 15, 2013. Group 7 has two configurations: Configuration 1 is for airplanes without a repair; Configuration 2 is for airplanes with a repair. We added paragraph (h)(2) to this proposed AD (in the SNPRM) to state, “For group 7, configuration 1 airplanes identified in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: Install the same type and same size fasteners as those previously removed from the airplane after accomplishing the open hole HFEC inspection specified in the introductory text of paragraph (h) of this AD.”

Request for AMOC Approval

ANA requested that the NPRM be revised to allow approved AMOCs for AD 2014-12-13. ANA stated that airplanes have AMOCs for AD 2014-12-23 for certain repairs done using certain Boeing 737-300/-400/-500 structural repair manuals or certain Boeing ODA forms. ANA stated that existing AMOCs should be considered for AMOC approval in the NPRM.

We agree with the commenter's request for the reasons provided above. We have redesignated paragraph (l)(4) of the proposed AD (in the NPRM) as paragraph (l)(5) in this proposed AD (in the SNPRM). We have added paragraph (l)(4) to this proposed AD (in the SNPRM) to allow AMOCs approved previously for AD 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014), as AMOCs for the corresponding provisions of paragraphs (g) and (h) of this AD.

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. We have redesignated paragraph (c) of the proposed AD (in the NPRM) as paragraph (c)(1) in this proposed AD and added paragraph (c)(2) to this proposed AD to state that “Installation of Supplemental Type Certificate (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.”

Request To Clarify the NPRM for Historical Accuracy

Boeing requested that the NPRM be revised to clarify the content for historical accuracy. Boeing stated that in the “Actions Since AD 2014-12-13 and 2015-21-08 Were Issued” paragraph of the preamble of the NPRM, the first paragraph described that a 2.375-inch long crack in the inspar upper skin was discovered since the issuance of AD 2014-12-13 and AD 2015-21-08. Boeing stated, however, the discovery of the crack led to the issuance of AD 2015-21-08 and not AD 2014-12-13. Boeing stated that the AD will become a reference for prior events, and therefore, historical accuracy is essential.

We agree with the commenter to clarify the historical accuracy of this SNPRM. While the paragraph, “Actions Since AD 2014-12-13 and 2015-21-08 Were Issued,” is not carried over in the SNPRM, we acknowledge that the discovery of a 2.375-inch long crack in the inspar upper skin led to the issuance of AD 2015-21-08. We have not changed this SNPRM regarding this issue.

FAA's Determination

We are proposing this SNPRM because we evaluated all the relevant information and determined the unsafe condition described previously is likely to exist or develop in other products of the same type design. Certain changes described above expand the scope of the NPRM. As a result, we have determined that it is necessary to reopen the comment period to provide additional opportunity for the public to comment on this SNPRM.

Proposed Requirements of This SNPRM

This SNPRM would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between this Proposed AD and the Service Information.” For information on the procedures and compliance times, see this service information at http://www.regulations.gov by searching for and locating Docket No. FAA-2016-9523.

The phrase “related investigative actions” is used in this SNPRM. Related investigative actions are follow-on actions that (1) are related to the primary action, and (2) further investigate the nature of any condition found. Related investigative actions in an AD could include, for example, inspections.

The phrase “corrective actions” is used in this SNPRM. Corrective actions correct or address any condition found. Corrective actions in an AD could include, for example, repairs.

Differences Between This SNPRM and the Service Information

Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016; and Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016; specify to contact the manufacturer for certain instructions, but this proposed AD would require accomplishment of repair methods, modification deviations, and alteration deviations in one of the following ways:

• In accordance with a method that we approve; or
• Using data that meet the certification basis of the airplane, and that have been approved by the Boeing Commercial Airplanes Organization Designation Authorization (ODA) whom we have authorized to make those findings.

Costs of Compliance

We estimate that this AD affects 471 airplanes of U.S. registry. We estimate the following costs to comply with this AD:

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

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.

This proposed AD is issued in accordance with authority delegated by the Executive Director, Aircraft Certification Service, as authorized by FAA Order 8000.51C. In accordance with that order, issuance of ADs is normally a function of the Compliance and Airworthiness Division, but during this transition period, the Executive Director has delegated the authority to issue ADs applicable to transport category airplanes to the Director of the System Oversight Division.

Regulatory Findings

We determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD would 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 this proposed regulation:

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

(2) Is not a “significant rule” under the 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

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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 adding the following new airworthiness directive (AD):

The Boeing Company: Docket No. FAA-2016-9523; Product Identifier 2016-NM-134-AD.

(a) Comments Due Date

The FAA must receive comments on this AD action by September 5, 2017.

(b) Affected ADs

This AD affects AD 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014), and AD 2015-21-08, Amendment 39-18301 (80 FR 65921, October 28, 2015).

(c) Applicability

(1) This AD applies to all The Boeing Company Model 737-100, -200, -200C, -300, -400, and -500 series airplanes, certificated in any category.

(2) Installation of Supplemental Type Certificate (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.

(d) Subject

Air Transport Association (ATA) of America Code 57, Wings.

(e) Unsafe Condition

This AD was prompted by reports of additional cracking in the inspar upper skin at Wing Buttock Line (WBL) 157 and in the skin at two holes common to the rear spar in the same area, and rear spar web cracks were also noted on both wings. Subsequent inspections revealed that the right rear spar upper chord was almost completely severed and the left rear spar upper chord was completely severed. We are issuing this AD to detect and correct cracking of the forward and aft support fittings for the main landing gear (MLG) beam, and the rear spar upper chord and rear spar web in the area of rear spar station (RSS) 224.14, which could grow and result in a fuel leak and possible fire.

(f) Compliance

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

(g) Required Actions for Group 1 Airplanes (MLG Support Fittings and Rear Spar)

For airplanes identified as Group 1 in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the applicable time specified in table 1 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, except as required by paragraph (j)(3) of this AD, do applicable inspections and corrective actions using a method approved in accordance with the procedures specified in paragraph (l) of this AD.

(h) Required Actions for Groups 2-7 Airplanes (MLG Support Fittings and Rear Spar)

For airplanes identified as Groups 2-7 in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: At the applicable time specified in table 2 through table 9 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, except as required by paragraph (j)(3) of this AD, do high frequency eddy current (HFEC) open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web at the 12 fastener holes (locations 1-12); or HFEC open hole inspections for any cracking in the forward support fitting, the aft support fitting, the rear spar upper chord, and the rear spar web, and an HFEC surface inspection for any cracking in the rear spar upper chord and rear spar upper web; as applicable; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, except as provided by paragraphs (h)(1) and (h)(2) of this AD, and except as required by paragraph (j)(1) of this AD. Do all applicable related investigative and corrective actions before further flight. Thereafter, repeat the HFEC inspection at the applicable time specified in table 2 through table 9 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016.

(1) Options provided in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, for accomplishing the inspection are acceptable for the corresponding requirements in the introductory text of paragraph (h) of this AD, provided that the inspections are done at the applicable times in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016.

(2) For Group 7, Configuration 1 airplanes identified in Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016: Install the same type and same size fasteners as those previously removed from the airplane after accomplishing the open hole HFEC inspection specified in the introductory text of paragraph (h) of this AD.

(i) Eddy Current Inspection (Inspar Upper Skin)

For airplanes identified in Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016: At the applicable time specified in table 1 and table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, except as required by paragraph (j)(2) of this AD, do an eddy current inspection of the left and right wings for any cracking in the inspar upper skin, and at the repair parts if installed, and do all applicable related investigative and corrective actions, in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, except as required by paragraph (j)(1) of this AD. Do all related investigative and corrective actions before further flight. Thereafter, repeat the eddy current inspection at the applicable time specified in table 1 and table 2 of paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016.

(j) Exceptions to the Service Information

(1) If any cracking is found during any inspection required by this AD, and Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016; or Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016; specifies to contact Boeing for appropriate action: Before further flight, repair using a method approved in accordance with the procedures specified in paragraph (l) of this AD.

(2) Where Boeing Alert Service Bulletin 737-57A1328, dated July 22, 2016, specifies a compliance time “after the Original Issue date of this service bulletin,” this AD requires compliance within the specified compliance time after the effective date of this AD.

(3) Where Boeing Alert Service Bulletin 737-57A1318, Revision 1, dated July 22, 2016, specifies a compliance time “after the Revision 1 date of this service bulletin, whichever occurs later,” this AD requires compliance within the specified compliance time after the effective date of this AD.

(k) Terminating Action

(1) Accomplishing the initial inspections and applicable related investigative and corrective actions required by paragraphs (g), (h), and (i) of this AD, as applicable, terminates all requirements of AD 2015-21-08.

(2) Accomplishing the initial inspections and applicable related investigative and corrective actions required by paragraphs (g) and (h) of this AD, as applicable, terminates all requirements of AD 2014-12-13.

(l) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Los Angeles Aircraft Certification Office (ACO) Branch, 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 certification office, send it to the attention of the person identified in paragraph (m)(1) of this AD. Information may be emailed to: 9-ANM-LAACO-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 Branch, 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 2014-12-13, Amendment 39-17874 (79 FR 39300, July 10, 2014), are approved as AMOCs for the corresponding provisions of paragraphs (g) and (h) of this AD.

(5) Except as required by paragraph (j)(1) of this AD: For service information that contains steps that are labeled as Required for Compliance (RC), the provisions of paragraphs (l)(5)(i) and (l)(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 sub-step is labeled “RC Exempt,” then the RC requirement is removed from that step or sub-step. 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.

(m) Related Information

(1) For more information about this AD, contact Payman Soltani, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5313; fax: 562-627-5210; email: payman.soltani@faa.gov.

(2) 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; telephone 562-797-1717; Internet https://www.myboeingfleet.com. You may view this referenced service information at the FAA, Transport Standards Staff, 1601 Lind Avenue SW., Renton, WA. For information on the availability of this material at the FAA, call 425-227-1221.