Airworthiness Directives; The Boeing Company Airplanes

AGENCY:

Federal Aviation Administration (FAA), DOT.

ACTION:

Final rule.

SUMMARY:

The FAA is adopting a new airworthiness directive (AD) for all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes. This AD was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting; this finding was on a Model 737-300 series airplane, which has a design similar to the Model 757 airplanes. This AD requires repetitive high frequency eddy current (HFEC) inspections for cracking of the lower aft wing skin aft edge at certain flap tracks, and repair if necessary. The FAA is issuing this AD to address the unsafe condition on these products.

DATES:

This AD is effective December 29, 2021.

The Director of the Federal Register approved the incorporation by reference of certain publications listed in this AD as of December 29, 2021.

ADDRESSES:

For Boeing 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. For Aviation Partners Boeing service information identified in this final rule, contact Aviation Partners Boeing, 2811 S 102nd Street, Suite 200, Seattle, WA 98168; telephone: 206-830-7699; internet: https://www.aviationpartnersboeing.com. You may view this service information 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. It is also available at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0262.

Examining the AD Docket

You may examine the AD docket at https://www.regulations.gov by searching for and locating Docket No. FAA-2021-0262; 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 final rule, any comments received, and other information. The address for Docket Operations is 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:

David Truong, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5224; email: david.truong@faa.gov.

SUPPLEMENTARY INFORMATION:

Background

The FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes. The NPRM published in the Federal Register on April 9, 2021 (86 FR 18482). The NPRM was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting. In the NPRM, the FAA proposed to require repetitive HFEC inspections for cracking of the lower aft wing skin aft edge at certain flap tracks, and repair if necessary. The FAA is issuing this AD to address undetected cracking in the lower aft wing skin, which could result in the inability of the structure to carry limit load and could adversely affect the structural integrity of the airplane.

Discussion of Final Airworthiness Directive

Comments

The FAA received comments from five commenters, including Aviation Partners Boeing, Delta Air Lines, United Airlines, FedEx, and Boeing. The following presents the comments received on the NPRM and the FAA's response to each comment.

Request for Correction of Typographical Error

Aviation Partners Boeing (APB) and Delta Air Lines (DAL) requested that references to “Aviation Partner Boeing” at several places in the proposed AD be corrected to “Aviation Partners Boeing.” APB noted that this typographical error appeared in paragraphs (g)(2), (h)(3), and (h)(4) of the proposed AD. DAL also noted the typographical error in the “Related Service Information Under 1 CFR Part 51” section of the proposed AD.

The FAA acknowledges the error and has corrected those references in this AD at the places noted.

Request for Revision of Required Actions Paragraph

DAL requested that the qualifying statement of paragraph (g)(2) of the proposed AD be revised or greater clarity added to paragraphs (g)(1) and (2) of the proposed AD regarding the status of aircraft modified in accordance with Aviation Partners Boeing Service Bulletin AP757-57-001, Revision 1, dated May 18, 2012, which removes winglets installed per supplemental type certificate (STC) ST01518SE. DAL stated that, because the compliance times for aircraft affected by Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, are shortened and additional inspection areas included, it is unlikely that accomplishment of Aviation Partners Boeing Service Bulletin AP757-57-001, Revision 1, dated May 18, 2012, would restore the aircraft to a configuration that could use the inspection times and locations defined in paragraph (g)(1) of the proposed AD, even though they would no longer be regarded as having blended winglets or scimitar blended winglets installed.

The FAA agrees with the request to revise the qualifying statement of paragraph (g)(2) of this AD. For aircraft modified in accordance with STC ST01518SE that subsequently have the STC winglets removed by Aviation Partners Boeing Service Bulletin AP757-57-001, Revision 1, dated May 18, 2012, the wing modification does not get removed, therefore Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, would still be applicable. The qualifying statement of paragraph (g)(2) of this AD has been changed to read, “For airplanes on which Aviation Partners Boeing blended winglets or scimitar blended winglets are installed using STC ST01518SE, or on which such winglets have been installed and subsequently removed.”

Request To Clarify Source of Findings

Boeing requested that the Summary and paragraph (e) of the proposed AD be rewritten to clarify that the unsafe condition prompting the proposed AD was not discovered on a Model 757 airplane. The commenter stated that the subject sentence may be misleading as is. Boeing noted that crack indications were found in a Model 737-300 airplane, which has a similar configuration to the Model 757 airplane in this area, but there are no reports of cracking in the area for a Model 757 airplane.

The FAA agrees with the request to clarify. The suggested clarification has been added to the Summary and paragraph (e) of this AD.

Request To Confirm Inspection Effectiveness

FedEx requested confirmation that the HFEC inspection described in Boeing Alert Service Bulletin 757-57A0074, dated June 11, 2020, will be sufficient to detect the described unsafe condition. FedEx noted that the proposed AD is based on a crack originating from a fastener hole. FedEx stated that, due to the relatively low depth penetration of HFEC, the inspection specified in the service information will not likely detect a crack until it has propagated through to the free edge of the lower aft wing skin.

The FAA has determined that the HFEC inspection will be sufficient to detect the unsafe condition. This is a proactive AD for the 757 fleet, based on a crack finding in a Model 737 airplane with a similar design. The unsafe condition exists when a fastener hole crack reaches the lower aft wing skin aft edge. Crack growth analysis has determined that the existing structural integrity of the Model 757 airplanes in this area is such that HFEC inspections at the intervals specified in the applicable service information would be able to detect a crack propagating from a fastener hole to the lower aft wing skin aft edge.

Request To Modify Proposed AD Requirements Paragraph

Boeing requested that the APB service information be added to the “Proposed AD Requirements in This NPRM” section of the NPRM. The commenter stated that the addition of the APB bulletin information in the statement would inform the reviewer of all applicable service information addressed by the proposed AD.

The FAA agrees that APB service information should have been included in the referenced section of the NPRM. However, the referenced section does not appear in this final rule. This AD has not been changed with regard to this request.

Request To Clarify Intent of Note

Boeing requested that “Note 1 to paragraph (g)” be changed to “Note 1 to paragraph (g)(1)” because as worded it implies that the Boeing service bulletin gives additional guidance for the APB bulletin, but it only gives additional guidance for the specified Boeing requirements bulletin.

The FAA agrees and has made the specified change.

Request To Modify Related Service Information Paragraph

United Airlines, DAL, and Boeing asked that the Related Service Information under 1 CFR part 51 paragraph be clarified to include HFEC inspections at flap track numbers 1 and 8 for aircraft with blended winglets or scimitar blended winglets. The commenters stated that the APB service bulletin requires additional inspections other than those required in the Boeing requirements bulletin. DAL noted that if the intent is to not require inspections at flap track numbers 1 and 8, paragraph (h) of the proposed AD should be revised to clarify that intent.

The FAA agrees with the request and notes that the intent is to require inspections at all flap track numbers specified in the applicable service information. The FAA has revised the “Related Service Information Under 1 CFR Part 51” section of this AD accordingly. The FAA has also revised the “Costs of Compliance” section to clarify the difference in work hours between the two bulletins.

Conclusion

The FAA reviewed the relevant data, considered any comments received, and determined that air safety requires adopting this AD as proposed. Except for minor editorial changes, and any other changes described previously, this AD is adopted as proposed in the NPRM. None of the changes will increase the economic burden on any operator.

Related Service Information Under 1 CFR Part 51

The FAA reviewed Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020. This service information specifies procedures for repetitive HFEC inspections for cracking of the lower aft wing skin aft edge at flap track numbers 2 and 7 attachment locations, and repair. The FAA also reviewed Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, which specifies procedures for repetitive HFEC inspections for cracking of the lower aft wing skin aft edge at flap track numbers 1, 2, 7, and 8 attachment locations, and repair. 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 ADDRESSES .

Costs of Compliance

The FAA estimates that this AD affects 483 airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD:

The FAA has received no definitive data on which to base the cost estimates for the on-condition repairs 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.

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

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) Will not affect intrastate aviation in Alaska, 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.

List of Subjects in 14 CFR Part 39

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

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 adding the following new airworthiness directive:

2021-22-23 The Boeing Company: Amendment 39-21796; Docket No. FAA-2021-0262; Project Identifier AD-2020-00815-T.

(a) Effective Date

This airworthiness directive (AD) is effective December 29, 2021.

(b) Affected ADs

None.

(c) Applicability

This AD applies to all The Boeing Company Model 757-200, -200PF, -200CB, and -300 series airplanes, certificated in any category.

(d) Subject

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

(e) Unsafe Condition

This AD was prompted by crack indications found in the lower aft wing skin bolt holes where the flap tracks attach to the track support fitting; this finding was on a Model 737-300 series airplane, which has a similar design to the Model 757 airplanes. The FAA is issuing this AD to address undetected cracking in the lower aft wing skin, which could result in the inability of the structure to carry limit load and could adversely affect the structural integrity of the airplane.

(f) Compliance

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

(g) Required Actions

(1) For all airplanes except those identified in paragraph (g)(2) of this AD: Except as specified by paragraph (h) of this AD, at the applicable times specified in the “Compliance” paragraph of Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020, do all applicable actions identified in, and in accordance with, the Accomplishment Instructions of Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020.

Note 1 to paragraph (g)(1): Guidance for accomplishing the actions required by this AD can be found in Boeing Alert Service Bulletin 757-57A0074, dated June 11, 2020, which is referred to in Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020.

(2) For airplanes on which Aviation Partners Boeing blended winglets or scimitar blended winglets are installed using supplemental type certificate (STC) ST01518SE, or on which they have been installed and subsequently removed: Except as specified by paragraph (h) of this AD, at the applicable times specified in paragraph 1.E., “Compliance” of Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, do all applicable actions identified as “RC” (required for compliance) in, and in accordance with, the Accomplishment Instructions of Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020.

(h) Exceptions to Service Information Specifications

(1) Where Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020, uses the phrase “the original issue date of Requirements Bulletin 757-57A0074 RB,” this AD requires using “the effective date of this AD.”

(2) Where Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020, specifies contacting Boeing for repair instructions: This AD requires doing the repair before further flight using a method approved in accordance with the procedures specified in paragraph (i) of this AD.

(3) Where Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, uses the phrase “the original issue date of this service bulletin,” this AD requires using “the effective date of this AD.”

(4) Where Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020, specifies contacting Boeing for repair instructions: This AD requires doing the repair before further flight using a method approved in accordance with the procedures specified in paragraph (i) of this AD.

(i) Alternative Methods of Compliance (AMOCs)

(1) The Manager, Los Angeles 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 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 Related Information. 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 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, Los Angeles ACO 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.

(j) Related Information

For more information about this AD, contact David Truong, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627-5224; email: david.truong@faa.gov.

(k) 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) Aviation Partners Boeing Alert Service Bulletin AP757-57-011, dated August 21, 2020.

(ii) Boeing Alert Requirements Bulletin 757-57A0074 RB, dated June 11, 2020.

(3) For Boeing 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. For Aviation Partners Boeing service information identified in this AD, contact Aviation Partners Boeing, 2811 S. 102nd Street, Suite 200, Seattle, WA 98168; telephone: 206-830-7699; internet: https://www.aviationpartnersboeing.com.

(4) You may view this service information 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 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, fr.inspection@nara.gov , or go to: https://www.archives.gov/federal-register/cfr/ibr-locations.html.