Discussion \n\n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 by adding an AD that would apply to certain The Boeing Company Model 757-200, -200CB, and -300 series airplanes. The NPRM published in the Federal Register on June 21, 2019 (84 FR 29102). The NPRM was prompted by reports of cracks initiating in the fuselage frame web at STA 1640. The NPRM proposed to require, depending on configuration, a general visual inspection for any previous repair, such as any reinforcing repair or local frame replacement repair, repetitive open hole HFEC inspections for any crack of the fuselage frame web fastener holes, on the left and right side of the airplane, and applicable on-condition actions. \n\tThe FAA is issuing this AD to address cracks initiating in the fuselage frame web at STA 1640, which could result in reduced structural integrity of the airplane. \n\nComments \n\n\n\tThe FAA gave the public the opportunity to participatein developing this final rule. The following presents the comments received on the NPRM and the FAA's response to each comment. \n\nSupport for the NPRM \n\n\n\tUnited Airlines and Aviation Partners Boeing (APB) provided their concurrence with the NPRM. \n\nRequest To Clarify Costs of Required Actions \n\n\n\tBoeing requested that the FAA clarify the costs of the actions required by the NPRM by separating the access and close-out hours as separate actions, and specifying that the on-condition costs are providing the costs of oversizing fastener holes, if necessary. Boeing pointed out that the costs listed also include the access and close-out hours, which comprise the majority of the hours for each action, causing the required actions to appear overly expensive. Boeing mentioned that operators are expected to do either a one-time general visual inspection, followed by an open hole HFEC inspection, or do an open hole HFEC inspection, depending on the condition and utilization rate of theairplane. Boeing also pointed out that the on-condition costs are not defined in the service information and that the NPRM is unclear if the on-condition costs refer to fastener replacement installations or fastener hole oversizing. Additionally, Boeing mentioned that the costs of fastener re-installation are already included in the costs for an open hole HFEC inspection. However, Boeing stated that the FAA estimate of one work-hour per airplane for on- condition costs of oversizing fastener holes seems reasonable. \n\tThe FAA agrees with the request to clarify the costs of the actions required by this AD for the reasons provided. The FAA has revised the cost estimates provided in this AD to clarify the costs of the required actions to include access and close-out hours only as part of the costs for the HFEC inspections, and to revise the work-hours for the general visual inspection to specify only 1 work-hour. We have also revised the cost estimates in this AD to specify that the on-condition costs are the costs of oversizing fastener holes. \n\nRequest To Clarify the Unsafe Condition \n\n\n\tBoeing requested that the FAA clarify the unsafe condition. Boeing pointed out that the unsafe condition mitigated by the proposed AD is for cracks initiating in the fuselage frame web at STA 1640 in hidden areas that may not be sufficiently detectable by doing the \n\n((Page 67180)) \n\nactions specified in Boeing Alert Service Bulletin 757-53A0108. \n\tThe FAA agrees that clarification is necessary and that the actions specified in Boeing Alert Service Bulletin 757-53A0108 are not adequate for reliable detection of cracks that initiate in the fuselage frame web at STA 1640. AD 2018-06-07, Amendment 39-19227 (83 FR 13398, March 29, 2018) (''AD 2018-06-07'') requires inspections in accordance with Boeing Alert Service Bulletin 757-53A0108, dated November 14, 2016. However, the FAA does not agree that referring to hidden areas is clarifying, because the term ''hidden areas'' is vague. The FAA has revised the unsafe condition specified in paragraph (e) of this AD to specify that this AD is addressing cracks initiating in the fuselage frame web at STA 1640, which, if not detected and corrected, could result in reduced structural integrity of the airplane. \n\nRequest To Clarify the Types of Winglets Specified in the Proposed AD \n\n\n\tBoeing requested that the FAA revise paragraph (g)(2) of the proposed AD to clarify the types of winglets that may be installed on The Boeing Company Model 757 airplanes. Boeing pointed out that the types of winglets described in Supplemental Type Certificate (STC) ST01518SE and in APB's service bulletin AP757-53-002 are specified as ''blended and scimitar blended winglets,'' not ''scimitar winglets.'' Boeing also pointed out that paragraph (g)(2) of the proposed AD referred to ''blended or scimitar winglets.'' \n\tThe FAA agrees for the reasons provided and has revised paragraph (g)(2) of this AD accordingly. \n\nRequest To SpecifyThat Certain Freighter Conversion Airplanes Perform the Actions Specified for Groups 2 and 5 \n\n\n\tFedEx and VT Mobile Aerospace Engineering (MAE) Inc., requested that the FAA revise the NPRM to specify that Group 1 and 4 airplanes that have been modified to freighter configuration using VT MAE Inc. STC ST03562AT, perform the actions specified for Groups 2 and 5, as specified in Boeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018. VT MAE Inc. pointed out that at the STA 1640 frame, in the stringer 14 left hand side and right hand side area, the modification to freighter configuration using VT MAE Inc. STC ST03562AT, is identical to that of The Boeing Company Model 757-200 special freighter airplanes identified as Groups 2 and 5 in Boeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018. FedEx noted that its fleet of The Boeing Company Model 757-200 airplanes were converted to a configuration similar to The Boeing Company Model 757-200 specialfreighter airplanes, and are no longer configured as passenger airplanes. FedEx pointed out that as written, Boeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018, Groups the FedEx fleet into Groups 1 and 4, and that the inspection areas for those Groups are no longer applicable. FedEx requested that the FAA incorporate its suggested changes into the final rule to avoid the need for an alternative method of compliance (AMOC) after issuance of the final rule. \n\tThe FAA agrees with the request for the reasons provided. The FAA has added paragraphs (g)(3) and (g)(4) of this AD to require, for airplanes that have been converted from passenger to freighter configuration using VT MAE Inc. STC ST03562AT, the actions required for Groups 2 and 5, as applicable, as specified in Boeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018. \n\nRequest To Terminate the Inspection Requirements if a Repair Is Installed for a Crack Finding \n\n\n\tFedEx requested that the FAA allow termination of the inspection requirements if a repair is installed for a crack finding. FedEx pointed out that if a repair is installed for a crack finding, the repair instructions obtained from The Boeing Company Organization Designation Authorization (ODA), the STC holder, or the FAA would have repetitive inspection requirements separate from those specified in the NPRM. The FAA infers that FedEx is requesting termination of the inspection requirements to help avoid overlapping inspections in a repaired area. \n\tThe FAA disagrees with the request to allow termination of the inspection requirements if a repair is installed for a crack finding. At this time, the service information does not include an approved repair that resolves the unsafe condition addressed by this AD. Inspections for repairs required by FAA regulations address structural failure due to fatigue, corrosion, manufacturing defects, or accidental damage, and do not resolve unsafe conditions that areaddressed by an AD. If a repair is required for cracks found during inspections required by this AD, the FAA will consider requests for approval of an AMOC. \n\nRequest To Specify That an AMOC for a Certain Other AD Is Necessary \n\n\n\tFedEx requested that the FAA include a statement in paragraph (i) of the proposed AD specifying that if a repair is required for a crack found during inspections required by the NPRM, that an AMOC for AD 2018-06-07 is required. FedEx mentioned that it has already experienced a situation that when repairing a crack found using Boeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018, an AMOC to AD 2018-06-07 was required to complete the repair. \n\tThe FAA disagrees with the request to include a statement in paragraph (j) of this AD (which was referred to as paragraph (i) of the proposed AD) specifying that if a repair is required for a crack found during inspections required by this AD, that an AMOC for AD 2018-06-07 is required. However, any repair in this area that affects compliance with this AD, with AD 2018-06-07, or with both ADs, will require an AMOC to comply with the requirements of the affected ADs. The FAA has included note 2 to paragraphs (g)(1) through (4) of this AD to denote that certain repairs might affect AD 2018-06-07. \n\nRequest To Allow Later Revisions to the Service Information \n\n\n\tJohn Straiton requested that the FAA revise the proposed AD to allow the use of later revisions to the service information. The commenter pointed out that allowing the use of later revisions would make it easier for the operator to ensure compliance and that all maintenance is certified to the latest maintenance data. The commenter also mentioned that allowing the use of later revisions would make it unnecessary for operators to wait for new ADs that include the latest revisions to the service information, or for operators to request an AMOC that allows the use of the latest revisions to the service information. The commenter stated that this would reduce the delay in implementation of the latest revisions to the service information and also reduce the maintenance costs associated with the issuance of AMOCs. The commenter also pointed out that the European Union Aviation Safety Agency (EASA) incorporates similar language in its ADs. \n\tThe FAA disagrees with the request to allow later revisions to the service information. The FAA may not refer to any document that does not yet exist in an AD. In general terms, the FAA is required by Office of the Federal Register (OFR) regulations for approval of materials incorporated by reference, \n\n((Page 67181)) \n\nas specified in 1 CFR 51.1(f), to either publish the service document contents as part of the actual AD language; or submit the service document to the OFR for approval as referenced material, in which case the FAA may only refer to such material in the text of an AD. The AD may refer to the service document only if the OFR approved it for incorporation by reference. See 1 CFR part 51. \n\tTo allow operators to use later revisions of the referenced document (issued after publication of the AD), either the FAA must revise the AD to reference specific later revisions, or the affected party must request approval to use later revisions as an AMOC with this AD under the provisions of paragraph (j) of this AD. \n\nRequest for an Exception to Certain Service Information \n\n\n\tAmerican Airlines (AAL) and APB requested that the FAA revise the proposed AD to include a new exception. AAL requested that the FAA include an exception that specifies ''Where APB Alert Service Bulletin AP757-53-002, Revision 2, dated April 11, 2019, uses the phrase the original issue of Service Bulletin AP757-53-001, this AD requires using the original issue, or Revision 1, of Service Bulletin AP757-53-001.'' APB pointed out that the original issue of APB Service Bulletin AP757- 53-001, was withdrawn. APB also stated their support for AAL's request. \n\tAAL also pointed out that while APB Alert Service Bulletin AP757- 53-002, Revision 2, dated April 11, 2019, specifies the original issue of APB Service Bulletin AP757-53-001, AD 2018-06-07 requires operators to use Revision 1 of APB Service Bulletin AP757-53-001. AAL noted that this creates conflicting verbiage between the NPRM and AD 2018-06-07. \n\tThe FAA agrees to clarify. The FAA notes that APB Alert Service Bulletin AP757-53-002, Revision 3, dated August 14, 2019, has been issued to correct the reference from the original issue of APB Service Bulletin AP757-53-001 to Revision 1 of APB Service Bulletin AP757-53- 001, as it relates to whether inspections have previously been done. No additional work is required for airplanes on which the actions specified in this AD were done using APB Alert Service Bulletin AP757- 53-002, Revision 2, dated April 11, 2019. The FAA has revised this final rule to refer to APB Alert Service Bulletin AP757-53-002, Revision 3, dated August 14, 2019, as the appropriate source of service information for compliance with this AD, and to provide credit for actions done before the effective date of this AD using APB Alert Service Bulletin AP757-53-002, Revision 2, dated April 11, 2019. \n\nConclusion \n\n\n\tThe FAA has reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting this final rule with the changes described previously and minor editorial changes. The FAA has determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for addressing the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tThe FAA also determined that these changes will not increase the economic burden on any operator or increase the scope of this final rule. \n\nRelated Service Information Under 1 CFR Part 51 \n\n\n\tThe FAA reviewed the following service information. \n\tAviation Partners Boeing Alert Service Bulletin AP757-53- 002, Revision 3, dated August 14, 2019. \n\tBoeing Alert Requirements Bulletin 757-53A0112 RB, dated November 16, 2018. \n\tThis service information describes procedures for, depending on configuration, a general visual inspection for any previous repair, such as any reinforcing repair or local frame replacement repair, repetitive open hole HFEC inspections for any crack of the fuselage frame web fastener holes, on the left and right side of the airplane, and applicable on-condition actions. On-condition actions include installation of fasteners, oversizing of fastener holes, and repair. These documents are distinct since they apply to different airplane models in different configurations. \n\tThis 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. \n\nCosts of Compliance \n\n\n\tThe FAA estimates that this AD affects 475airplanes of U.S. registry. The FAA estimates the following costs to comply with this AD: \n\n\n\tEstimated Costs for Required Actions ---------------------------------------------------------------------------------------------------------------- \n\tCost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- General Visual Inspection........ 1 work-hours x $85 $0 $85................ $40,375. \n\tper hour = $85. Open Hole HFEC Inspection........ 35 work-hours x $85 0 $2,975 per $1,413,125 per \n\tper hour = $2,975 inspection cycle. inspection cycle. \n\tper inspection \n\tcycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tThe FAA estimates the following costs to do any necessary on- condition installation of fasteners and oversizing of fastener holes that is required. The FAA has no way of determining the number of aircraft that might need these on-condition actions: \n\nEstimated Costs of On-Condition Installation of Fasteners and Oversizing \n\tof Fastener Holes ------------------------------------------------------------------------ \n\tCost per \n\tLabor cost Parts cost product ------------------------------------------------------------------------ 1 work-hour x $85 per hour = $85...... $0 $85 ------------------------------------------------------------------------ \n\n\n\n((Page 67182)) \n\n\n\tWe have received no definitive data that would enable us to provide cost estimates for the on-condition repairs specified in this AD. \n\nAuthority for This Rulemaking \n\n\n\tTitle 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 theFAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tThe 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. \n\tThis 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 and associated appliances to the Director of the System Oversight Division. \n\nRegulatory Findings \n\n\n\tThis 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a ''significant regulatory action'' under Executive Order 12866, \n\t(2) Will not affect intrastate aviation in Alaska, and \n\t(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. \n\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.