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 Department of Transportation Federal Aviation Administration 14 CFR Part 39
[Docket No. FAA-2024-2315; Project Identifier AD-2023-00537-T]
RIN 2120-AA64
 AGENCY: Federal Aviation Administration (FAA), DOT.
 ACTION: Notice of proposed rulemaking (NPRM).
 SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) for certain The Boeing Company Model 737-800 series airplanes. This proposed AD was prompted by a determination that the compliance time for the initial ultrasonic inspection required by AD 2019-11-06 is insufficient for certain airplanes. This proposed AD would require reducing the compliance time for the ultrasonic inspection of the skin under the drag link assembly. The FAA is proposing this AD to address the unsafe condition on these products.
 DATES: The FAA must receive comments on this proposed AD by November 12, 2024.
 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 
                        *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. *AD Docket:*
                         You may examine the AD docket at 
                        *regulations.gov*
                         under Docket No. FAA-2024-2315; or in person at Docket Operations between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains this NPRM, any comments received, and other information. The street address for Docket Operations is listed above. *Material Incorporated by Reference:* For Boeing material identified in this NPRM, 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; website*myboeingfleet.com*.
                    You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA.
 FOR FURTHER INFORMATION CONTACT: Owen Bley-Male, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3992; email: 
                        *owen.f.bley-male@faa.gov.*


SUPPLEMENTARY INFORMATION:  Comments Invited The FAA invites you to send any written relevant data, views, or arguments about this proposal. Send your comments to an address listed under 
                    **ADDRESSES**
                    . Include “Docket No. FAA-2024-2315; Project Identifier AD-2023-00537-T” at the beginning of your comments. The most helpful comments reference a specific portion of the proposal, explain the reason for any recommended change, and include supporting data. The FAA will consider all comments received by the closing date and may amend this proposal because of those comments. Except for Confidential Business Information (CBI) as described in the following paragraph, and other information as described in 14 CFR 11.35, the FAA will post all comments received, without change, to 
                    *regulations.gov,*
                     including any personal information you provide. The agency will also post a report summarizing each substantive verbal contact received about this NPRM. Confidential Business Information CBI is commercial or financial information that is both customarily and actually treated as private by its owner. Under the Freedom of Information Act (FOIA) (5 U.S.C. 552), CBI is exempt from public disclosure. If your comments responsive to this NPRM contain commercial or financial information that is customarily treated as private, that you actually treat as private, and that is relevant or responsive to this NPRM, it is important that you clearly designate the submitted comments as CBI. Please mark each page of your submission containing CBI as “PROPIN.” The FAA will treat such marked submissions as confidential under the FOIA, and they will not be placed in the public docket of this NPRM. Submissions containing CBI should be sent to Owen Bley-Male, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3992; email: 
                    *owen.f.bley-male@faa.gov.*
                     Any commentary that the FAA receives that is not specifically designated as CBI will be placed in the public docket for this rulemaking. Background The FAA issued AD 2019-11-06, Amendment 39-19652 (84 FR 27193, June 12, 2019) (AD 2019-11-06) for certain The Boeing Company Model 737-600, 737-700, 737-700C, 737-800, 737-900, and 737-900ER series airplanes. AD 2019-11-06 requires ultrasonic inspections of the skin under the drag link assembly for cracks and applicable on-condition actions. The FAA issued AD 2019-11-06 to address cracking in the station (STA) 540 bulkhead chord or skin, which could result in the inability of a primary structural element to sustain limit load. Since issuing AD 2019-11-06, the FAA has received a report that, for Model 737-800 series airplanes that have been modified to a freighter configuration using Boeing Drawing 800A0003, an evaluation of structural stresses using revised stress level calculations found that the inspection thresholds required by AD 2019-11-06 were insufficient. Those airplanes are subject to additional structural stresses due to the modifications done during conversion to a freighter configuration. Therefore, the compliance times for the initial inspections required by AD 2019-11-06 could be performed on those airplanes after the appropriate inspection threshold has passed, which could result in undetected cracking in the STA 540 bulkhead chord or skin. The FAA determined that, for those airplanes, a reduced compliance time is 
                    ( print page 78261)
                    needed to address the unsafe condition. Accomplishing the actions required by this proposed AD would replace the initial ultrasonic inspections required by paragraph (g) of AD 2019-11-06 for Model 737-800 airplanes converted to a freighter configuration using Boeing Drawing 800A0003. This condition, if not addressed, could lead to undetected cracking in the STA 540 bulkhead chord or skin, which could result in possible rapid decompression and loss of structural integrity of the airplane. FAA's Determination The FAA is issuing this NPRM after determining that the unsafe condition described previously is likely to exist or develop on other products of the same type design. Material Incorporated by Reference Under 1 CFR Part 51 The FAA reviewed Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018. This material specifies an ultrasonic inspection of the skin under the drag link assembly and repair for any cracks; repetitive inspections for any cracks, including ultrasonic inspections, high frequency eddy current inspections, low frequency eddy current inspections, and detailed inspections; and a preventative modification if no crack is found. The FAA also reviewed Boeing 737-800BCF Airworthiness Limitations, D140A006, Revision L, dated April 1, 2021. This material contains required inspections for principal structural element items. Section 5.2.1 of this material identifies the airplanes affected by this proposed AD. This material is reasonably available because the interested parties have access to it through their normal course of business or by the means identified in 
                    **ADDRESSES**
                    . Proposed AD Requirements in This NPRM This proposed AD would reduce the compliance time for the initial ultrasonic inspection required by AD 2019-11-06 for Model 737-800 series airplanes that have been converted to a freighter configuration using Boeing Drawing 800A0003. Costs of Compliance The FAA estimates that this AD, if adopted as proposed, would affect 18 airplanes of U.S. registry. The FAA estimates the following costs to comply with this proposed AD: Estimated Costs for Required Actions
Action
Labor cost
Parts cost
Cost per
                             product
Cost on U.S.
                             operatorsInitial inspection
Up to 23 work-hours × $85 per hour = $1,955
$0
$1,955
Up to $35,190.
 The FAA estimates the following costs to do any on-condition actions that would be required based on the results of the proposed inspection. The agency has no way of determining the number of airplanes that might need these actions: Estimated Costs for On-Condition Actions
Labor cost
Parts cost
Cost per productUp to 56 work-hours × $85 per hour = $4,760
$24,020
Up to $28,780.
 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. The FAA is 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 The FAA 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) Would not affect intrastate aviation in Alaska, and (3) Would 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. § 39.13
 2.The FAA amends § 39.13 by adding the following new airworthiness directive: **The Boeing Company:**
                         Docket No. FAA-2024-2315; Project Identifier AD-2023-00537-T. (a) Comments Due Date The FAA must receive comments on this airworthiness directive (AD) by November 12, 2024.
                        ( print page 78262) (b) Affected ADs This AD affects AD 2019-11-06, Amendment 39-19652 (84 FR 27193, June 12, 2019) (AD 2019-11-06). (c) Applicability This AD applies to The Boeing Company Model 737-800 series airplanes, certificated in any category, that have been converted to a freighter configuration using Boeing Drawing 800A0003 before April 1, 2021, and are identified as Group A in Section 5.2.1, “Effectivity,” of Boeing 737-800BCF Airworthiness Limitations, D140A006, Revision L, dated April 1, 2021. Note 1 to paragraph (c): Airplanes with a 737-800BCF designation are Model 737-800 series airplanes that have been converted to a freighter configuration using Boeing Drawing 800A0003. (d) Subject Air Transport Association (ATA) of America Code 53, Fuselage. (e) Unsafe Condition This AD was prompted by a determination that the compliance time for the initial ultrasonic inspection of the skin under the drag link assembly required by AD 2019-11-06 must be reduced for certain airplanes. The FAA is issuing this AD to address cracking found in the station (STA) 540 bulkhead chord and skin, which could result in the inability of a primary structural element to sustain limit load. The unsafe condition, if not addressed, could result in possible rapid decompression and loss of structural integrity of the airplane. (f) Compliance Comply with this AD within the compliance times specified, unless already done. (g) Required Actions (1) For airplanes identified as Group 1, Configuration 2, 3, 4, or 5, or as Group 5 in Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018: At the compliance time specified in paragraph (g)(1)(i), (ii), (iii), or (iv) of this AD, whichever occurs last, perform an ultrasonic inspection of the skin under the drag link assembly in accordance with the Accomplishment Instructions, Part 2, of Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018. Do all applicable on-condition actions for the Part 2 inspection at the times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018, except where Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018, specifies contacting Boeing for repair instructions, this AD requires doing the repair using a method approved in accordance with paragraph (j) of this AD. (i) Before the airplane accumulates 17,000 total flight cycles. (ii) Within 5,000 flight cycles after July 17, 2019 (the effective date of AD 2019-11-06). (iii) Within 12 months after the effective date of this AD. (iv) Within 1,000 flight cycles after the effective date of this AD. (2) For airplanes identified as Group 1, Configuration 1, 3, or 4 in Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018: At the compliance time specified in paragraph (g)(2)(i), (ii), (iii), or (iv) of this AD, whichever occurs last, perform an ultrasonic inspection of the repair tripler under the drag link assembly in accordance with the Accomplishment Instructions, Part 6, of Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018. Do all applicable on-condition actions for the Part 6 inspection at the times specified in paragraph 1.E., “Compliance,” of Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018, except where Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018, specifies contacting Boeing for repair instructions, this AD requires doing the repair using a method approved in accordance with paragraph (j) of this AD. (i) Before the airplane accumulates 30,000 total flight cycles. (ii) Within 5,000 flight cycles after July 17, 2019 (the effective date of AD 2019-11-06). (iii) Within 12 months after the effective date of this AD. (iv) Within 1,000 flight cycles after the effective date of this AD. (i) Terminating Action for Certain Requirements of AD 2019-11-06 Accomplishing the actions required by this AD replaces the corresponding initial ultrasonic inspections and on-condition actions required by paragraph (g) of AD 2019-11-06 for Model 737-800 airplanes converted to a freighter configuration using Boeing Drawing 800A0003 only. (j) Alternative Methods of Compliance (AMOCs) (1) The Manager, AIR-520, Continued Operational Safety 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 responsible Flight Standards 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 (k) of this AD. Information may be emailed to: 
                        *AMOC@faa.gov.* (2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager of the responsible Flight Standards 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 Company Organization Designation Authorization (ODA) that has been authorized by the Manager, AIR-520, Continued Operational Safety Branch, FAA, 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. (k) Related Information For more information about this AD, contact Owen Bley-Male, Aviation Safety Engineer, FAA, 2200 South 216th St., Des Moines, WA 98198; phone: 206-231-3992; email: 
                        *owen.f.bley-male@faa.gov.* (l) Material Incorporated by Reference (1) The Director of the Federal Register approved the incorporation by reference of the material listed in this paragraph under 5 U.S.C. 552(a) and 1 CFR part 51. (2) You must use this material as applicable to do the actions required by this AD, unless the AD specifies otherwise. (i) Boeing 737-800BCF Airworthiness Limitations, D140A006, Revision L, dated April 1, 2021. (ii) Boeing Alert Service Bulletin 737-53A1368, dated February 27, 2018. (3) For Boeing material 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; website 
                        *myboeingfleet.com*. (4) You may view this material at the FAA, Airworthiness Products Section, Operational Safety Branch, 2200 South 216th St., Des Moines, WA. For information on the availability of this material at the FAA, call 206-231-3195. (5) You may view this material at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, visit 
                        *www.archives.gov/​federal-register/​cfr/​ibr-locations*
                         or email 
                        *fr.inspection@nara.gov.* Issued on September 19, 2024. Peter A. White, Deputy Director, Integrated Certificate Management Division, Aircraft Certification Service.


[FR Doc. 2024-21813 Filed 9-24-24; 8:45 am] BILLING CODE 4910-13-P