AD 2017-22-12

We are adopting a new airworthiness directive (AD) for all The Boeing Company Model 757-200, -200PF, and -200CB series airplanes. This AD was prompted by reports of slats disbonding on airplanes on which the terminating actions of AD 2005-07-08 had been performed. We have also received reports of slats disbonding on airplanes outside of the applicability of AD 90-23-06, AD 91-22-51, and AD 2005-07-08, which also addressed slat disbonding. This AD requires determining the type of trailing edge slat wedges of the leading edge slats, repetitive inspections for disbonding on certain trailing edge slat wedges, and corrective actions if necessary. This AD also provides an optional terminating action for the repetitive inspections. We are issuing this AD to address the unsafe condition on these products.

Final rule.

Adoption of the Amendment \n\n\n\tAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n0 1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n0 2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD): \n\n2017-22-12 The Boeing Company: Amendment 39-19092; Docket No. FAA- 2017-0249; Product Identifier 2016-NM-138-AD. \n\n(a) Effective Date \n\n\n\tThis AD is effective December 26, 2017. \n\n(b) Affected ADs \n\n\n\tThis AD affects AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990) (''AD 90-23-06''); AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992) (''AD 91-22-51''); and AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005) (''AD 2005-07- 08''). \n\n(c) Applicability \n\n\n\t(1) This AD applies to all The Boeing Company Model 757-200, - 200PF, and -200CB series airplanes, certificated in any category. \n\t(2) Installation of Supplemental Type Certificate (STC) ST01518SE (http://rgl.faa.gov/Regulatory_and_Guidance_Library/ rgSTC.nsf/0/38b606833bbd98b386257faa00602538/$FILE/ST01518SE.pdf) does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01518SE 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. \n\n(d) Subject \n\n\n\tAir Transport Association (ATA) of America Code 57, Wings. \n\n(e) Unsafe Condition \n\n\n\tThis AD was prompted by reports of slats disbonding on airplanes on which the terminating actions of AD 2005-07-08 had been performed. We have also received reports of slats disbonding on airplanes outside of the applicability of AD 90-23-06, AD 91-22-51, and AD 2005-07-08, which also addressed slat disbonding. We are issuing this AD to prevent delamination of the trailing edge slat wedges of the leading edge slats. This delamination could cause loss of pieces of the trailing edge slat wedge assemblies during flight, reduction of the maneuver and stall margins, and consequent reduced controllability of the airplane. \n\n(f) Compliance \n\n\n\tComply with this AD within the compliance times specified, unless already done. \n\n(g) Inspection To Determine Slat Wedge Type \n\n\n\tAt the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing Special Attention Service Bulletin 757-57- 0066, Revision 1, dated June 7, 2016 (''Boeing SASB 757-57-0066 R1''), except as specified in paragraph (j)(1) of this AD: Inspect each trailing edge slat wedge of the leading edge slats in accordance with Appendixes A, B, C, and D of Boeing SASB 757-57-0066 R1, as applicable, or review the airplane maintenance records, to determine whether the slat wedge is a type A or a type B. If a maintenance records review cannot conclusivelydetermine a slat wedge is a type B, it must be assumed to be a type A slat wedge, or a physical inspection must be done as specified in this paragraph. If a physical inspection cannot determine if a slat wedge is a type A or type B slat wedge, it must be assumed to be a type A slat wedge, or approval of an alternative method of compliance (AMOC) may be requested in accordance with the procedures specified in paragraph (n) of this AD. \n\n((Page 55031)) \n\n(h) Type A Slat Wedge Repetitive Inspections, Related Investigative Actions, and Corrective Actions \n\n\n\tFor each type A trailing edge slat wedge found during the inspection or records review required by paragraph (g) of this AD: At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1, except as specified in paragraph (j)(1) of this AD, do an ultrasonic low frequency bond test inspection, a tap test inspection, or a through transmission ultrasonic (TTU) inspection for skin-to-core disbondsof the honeycomb area of the trailing edge slat wedge; do a detailed inspection for aft edge disbonds of the aft edge of the trailing edge slat wedge; do a general visual inspection for any previously accomplished repair; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, except as specified in paragraphs (i) and (j)(2) of this AD. Do all applicable related investigative and corrective actions at the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57- 0066 R1. Repeat the applicable inspections on each type A trailing edge slat wedge thereafter at the applicable intervals specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1. \n\n(i) Repaired Type A Slat Wedge Repetitive Inspections, Related Investigative Actions, and Corrective Actions \n\n\n\t(1) For each type A trailing edge slat wedge with any class 1 disbond repair or any previouslyaccomplished repair subject to the Part 2 inspection as identified in Boeing SASB 757-57-0066 R1: At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1, do an ultrasonic low frequency bond test inspection, a tap test inspection, or a TTU inspection for skin-to- core disbonds in the repaired area of the trailing edge slat wedge; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, except as specified in paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection on each type A trailing edge slat wedge thereafter at the applicable interval specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57- 0066 R1. \n\t(2) For each type A trailing edge slat wedge with any time- limited class 2 disbond repair as identified in Boeing SASB 757-57- 0066 R1: At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1, do a detailed inspection for any peeling or deterioration of the aluminum foil tape of the repaired area on the trailing edge slat wedge; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757- 57-0066 R1, except as specified in paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection on each type A trailing edge slat wedge thereafter at the applicable interval specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57- 0066 R1, until a permanent repair is done to complete the actions required for the time-limited class 2 disbond repair, specified as corrective actions in paragraph (h) of this AD. \n\t(3) For each type A trailing edge slat wedge with any permanent class 2 disbond repair as identified in Boeing SASB 757-57-0066 R1: At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1, do an ultrasonic low frequency bond test inspection or a TTU inspection for any disbonding of the aft edge repaired areas; a detailed inspection for disbonds along the aft edge of the repaired areas; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, except as specified in paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection on each type A trailing edge slat wedge thereafter at the applicable interval specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1. \n\t(4) For each type A trailing edge slat wedge with any class 3 or class 4 disbond repair, or any previously accomplished repair subject to Part 5 inspection as identified in Boeing SASB 757-57- 0066 R1: At the applicable time specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1, do the applicable actions specified in paragraphs (i)(4)(i) and (i)(4)(ii) of this AD. \n\t(i) For any class 3 disbond repair with a repair doubler common to the aft edge of the trailing edge slat wedge; for any previously accomplished repair with a repair doubler common to the aft edge of the trailing edge slat wedge; and for any class 4 disbond repair: Do an ultrasonic low frequency bond test inspection or a TTU inspection for any disbonding of the aft edge repaired areas; a detailed inspection for disbonds along the aft edge of the repaired areas; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, except as specified in paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection on each type A trailing edge slatwedge thereafter at the applicable interval specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57- 0066 R1. \n\t(ii) For any class 3 disbond repair without a repair doubler common to the aft edge of the trailing edge slat wedge; and for any previously accomplished repair without a repair doubler common to the aft edge of the trailing edge slat wedge: Do an ultrasonic low frequency bond test inspection, a tap test inspection, or a TTU inspection for skin-to-core disbonds of the honeycomb area of the trailing edge slat wedge in the repaired area; and do all applicable related investigative and corrective actions; in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, except as specified in paragraph (j)(2) of this AD. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection on each type A trailing edge slat wedge thereafter at the applicable interval specified in paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57-0066 R1. \n\n(j) Exceptions To Service Information \n\n\n\t(1) Where paragraph 1.E., ''Compliance,'' of Boeing SASB 757-57- 0066 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. \n\t(2) If any disbonding is found during any inspection required by this AD, and Boeing SASB 757-57-0066 R1, specifies to contact Boeing for appropriate action: Before further flight, repair the disbonding using a method approved in accordance with the procedures specified in paragraph (n) of this AD. \n\n(k) Optional Terminating Action for Repetitive Inspections \n\n\n\tReplacing a type A trailing edge slat wedge with a type B trailing edge slat wedge terminates the repetitive inspections required by this AD for that wedge if the replacement is done in accordance with the Accomplishment Instructions of Boeing SASB 757- 57-0066 R1; or Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003; or by determining, in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066, Rl, Appendixes A, B, C, and D (as applicable), that the current wedge installed on the slat is a type B. \n\n(l) Terminating Action for Certain Other ADs \n\n\n\t(1) Accomplishing the initial inspections required by paragraphs (g) and (h) of this AD on a trailing edge slat wedge terminates all of the requirements of AD 90-23-06, AD 91-22-51, and AD 2005-07-08 for that slat wedge. \n\t(2) Accomplishing the initial inspections required by paragraphs (g) and (h) of this AD on all trailing edge slat wedges terminates all of the requirements of AD 90-23-06, AD 91-22-51, and AD 2005-07- 08. \n\n(m) Parts Installation Limitation \n\n\n\tAs of the effective date of this AD: A replacement type A wedge may be installed provided that the initial and repetitive inspections and all applicable related investigative and corrective actions specified in paragraphs (h) and (i) of this AD are done within the applicable compliance times specified in paragraphs (h) and (i) of this AD. \n\n(n) Alternative Methods of Compliance (AMOCs) \n\n\n\t(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 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 (o) of this AD. Information may be emailed to: 9-ANM-LAACO-AMOC-Requests@faa.gov. \n\t(2) Before using any approved AMOC, notify your appropriate principal inspector, or lacking a principal inspector, the manager \n\n((Page 55032)) \n\nof the local flight standards district office/certificate holding district office. \n\t(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. \n\t(4) Except as required by paragraph (j)(2) of this AD: For service information that contains steps that are labeled as Required for Compliance (RC), the provisions of paragraphs (n)(4)(i) and (n)(4)(ii) of this AD apply. \n\t(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. \n\t(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. \n\n(o) Related Information \n\n\n\tFor more information about this AD, contact Chandra Ramdoss, Aerospace Engineer, Airframe Section, FAA, Los Angeles ACO Branch, 3960 Paramount Boulevard, Lakewood, CA 90712-4137; phone: 562-627- 5239; fax: 562-627-5210; email: chandraduth.ramdoss@faa.gov. \n\n(p) Material Incorporated by Reference \n\n\n\t(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. \n\t(2) You must use this service information as applicable to do the actions required by this AD, unless the AD specifies otherwise. \n\t(3) The following service information was approved for IBR on December 26, 2017. \n\t(i) Boeing Special Attention Service Bulletin 757-57-0066, Revision 1, dated June 7, 2016. \n\t(ii) Reserved. \n\t(4) The following service information was approved for IBR on May 5, 2005 (70 FR 16403, March 31, 2005). \n\t(i) Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003. \n\t(ii) Reserved. \n\t(5) 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. \n\t(6) You may view this 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. \n\t(7) 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.

Discussion \n\n\n\tWe 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, and -200CB series airplanes. The NPRM published in the Federal Register on April 13, 2017 (82 FR 17773). The NPRM was prompted by reports of slats disbonding on airplanes on which the terminating actions of AD 2005-07-08, Amendment 39-14032 (70 FR 16403, March 31, 2005) (''AD 2005-07-08'') had been performed. We have also received reports of slats disbonding on airplanes outside of the applicability of AD 90-23-06, Amendment 39-6794 (55 FR 46499, November 5, 1990) (''AD 90-23-06''), AD 91-22-51, Amendment 39-8129 (57 FR 781, January 9, 1992) (''AD 91-22-51''), and AD 2005-07-08, which also addressed slat disbonding. The NPRM proposed to require determining the type of trailing edge slat wedges of the leading edge slats, repetitive inspections for disbonding on certain trailing edge slat wedges, and corrective actions if necessary. The NPRM also proposed to provide an optional terminating action for the repetitive inspections. We are issuing this AD to prevent delamination of the trailing edge slat wedges of the leading edge slats. This delamination could cause loss of pieces of the trailing edge slat wedge assemblies during flight, reduction of the maneuver and stall margins, and consequent reduced controllability of the airplane. \n\nComments \n\n\n\tWe gave the public the opportunity to participate in 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\tThe Air Line Pilots Association, International and Boeing expressed support for the NPRM. \n\nRequests To Withdraw the NPRM \n\n\n\tAmerican Airlines (AAL) and Delta Air Lines (DAL) requested that we provide justification for the NPRM. AAL stated that the condition addressed by the NPRM is not an airplane-level safety issue, and does not meet the requirements for rulemaking activity because it does not correct an unsafe condition. DAL stated that Boeing's assessment, based on a piloted simulation study and pilot comments from flight testing, determined that the loss of slat wedges for slats 1 through 10 is a non-airplane-safety issue. \n\tWe infer that the commenters request that we withdraw the NPRM. We do not agree with the commenters' request. We have assessed the safety concern and have determined that there is insufficient flight test data to substantiate flight control authority to counteract rolling moment due to the loss of a slat trailing edge wedge. The Boeing analysis did not address maneuvering flight and critical (minimum) speeds or altitudes for recovery. We have therefore determined \n\n((Page 55028)) \n\nthat there is an unsafe condition that must be addressed, and we are issuing this final rule with the changes described below. \n\nRequest To Clarify the AD Applicability \n\n\n\tFedEx Express (FedEx) requested that we clarify whether the FedEx Model 757 fleet is affected by the NPRM. FedEx stated that paragraph (c) of the proposed AD does not reflect the FedEx Model 757-200 converted freighter configuration via supplemental type certificate (STC) ST03562AT (http://rgl.faa.gov/Regulatory_and_Guidance_Library/ rgstc.nsf/0/7239683609eb1b4086257ff1004d0f2b/$FILE/ST03562AT.pdf). \n\tWe agree that clarification is necessary. Paragraph (c) of this AD includes all Boeing Model 757-200, -200CB, and -200PF series airplanes in the applicability. FedEx airplanes were originally delivered as Model 757-200 series airplanes; installation of the freighter conversion supplemental type certificate on those airplanes does not change their airplane model designation. Therefore, Model 757-200 series airplanes that are converted to a freighter configuration are included in the applicability of this AD. We have not changed this AD in this regard. \n\nRequests To Specify Applicable Service Information Appendixes \n\n\n\tUnited Parcel Service (UPS), United Airlines (UAL), and DAL requested that we revise paragraph (g) of the proposed AD to specify that the inspection of each trailing edge slat wedge of the leading edge slats is done in accordance with the ''applicable'' Appendixes A, B, C, and D of the service information. The commenters explained that not all of the appendixes of the service information are applicable to each slat. \n\tWe agree with the commenters' request because each appendix applies only to inboard slats or outboard slats. We have revised paragraph (g) of this AD accordingly. \n\nRequest To Address Operator-Produced-and-Modified Slat Wedges \n\n\n\tAAL requested that we revise paragraph (g) of the proposed AD with specific wording to address operator-produced-and-modified slat wedges that carry owner-operator part numbers that are not addressed in Boeing Special Attention Service Bulletin 757-57-0066, Revision 1, dated June 7, 2016 (''Boeing SASB 757-57-0066 R1''). AAL explained that many operators have produced slat wedges internally, and there is no wording in the proposed AD to indicate how operator-produced wedges should be handled for inspections, terminating action, or parts installation limitations. \n\tWe agree to revise paragraph (g) of this AD by adding that if a physical inspection cannot determine if a slat wedge is a type A or type B slat wedge, it must be assumed to be a type A slat wedge, or an alternative method of compliance (AMOC) can be requested in accordance with the procedures specified in paragraph (n) of this AD. \n\nRequest To Clarify Differences Between the Structural Repair Manual (SRM) and Service Information \n\n\n\tUPS stated that FAA-approved SRM allowable damage and repairs must coincide fully with the service information specifications. UPS provided several examples of differences between the SRM and the service information. \n\tBoeing has informed us that a new revision of the SRM was released on September 20, 2017, to specify actions that are consistent with Boeing SASB 757-57-0066 R1. The new SRM revision will have the same procedures for type A and type B wedges, but different limitations. We have not changed this AD in this regard. \n\nRequests To Clarify Compliance Time \n\n\n\tFedEx and Jet2.com (CEX) requested clarification of the compliance time in Table 6 of paragraph 1.E., ''Compliance,'' of Boeing SASB 757- 57-0066 R1. FedEx explained that because the components are rotable, the compliance time should be based on component flight cycles or flight time while the component is installed on-wing, and not based on airplane flight cycles. FedEx noted that the specified repetitive inspection interval is 600 cycles or 6 months, whichever occurs first; FedEx interpreted this compliance time to mean 600 aircraft flight cycles or 6-months calendar time. FedEx also recommended the 6-months calendar time be revised to specify ''6 months of component on-wing time.'' CEX stated that the 6-months calendar time should not apply to components that are sitting on the shelf. \n\tWe agree to clarify the compliance times in this AD. The flight cycles in Table 6 of Boeing SASB 757-57-0066 R1, are component flight cycles. Table 6 of Boeing SASB 757-57-0066 R1, specifies the initial compliance time as ''Within 600 Trailing Edge Wedge flight cycles or within 6 months after the disbond is repaired or any previously accomplished repair is found, whichever occurs first'' and, for the repetitive interval, specifies ''600 Trailing Edge Wedge flight cycles or 6 months, whichever occurs first.'' If the trailing edge wedge is moved between airplanes, the flight cycles on the trailing edge wedge need to be tracked separately from the airplane flight cycles. \n\tWe disagree with the commenter's statements that the 6-month compliance time for the repetitive interval is intended to be 6 months while the component is installed on-wing. The 6-month calendar time limitation is necessary because bonding corrosion is a primary component of damage growth and corrosion might occur while the component is off-wing. We have coordinated this calendar time limitation with Boeing. It is not necessary to inspect a slat wedge during its time in storage, but if the inspection interval has been surpassed, the wedge would require inspection before being returned to service. We have not changed this AD in this regard. \n\nRequest To Supersede ADs \n\n\n\tFedEx requested that we revise the language in paragraph (l) of the proposed AD from terminating the requirements of other ADs to superseding the requirements in the other ADs. FedEx provided no technical justification for its request. \n\tWe do not agree with the commenter's request to revise the language in paragraph (l) of this AD. We use the terminology ''supersedes'' only if an AD action supersedes an existing AD. This AD is a stand-alone AD. As specified in paragraph (l)(1) of this AD (which we referred to as paragraph (l) of the proposed AD), accomplishing initial inspections required by paragraphs (g) and (h) of this AD on a trailing edge slat wedge terminates all requirements of AD 90-23-06, AD 91-22-51, and AD 2005-07-08 for that slat wedge. We have also added paragraph (l)(2) to this AD to clarify that accomplishing the initial inspections required by paragraphs (g) and (h) of this AD on all trailing edge slat wedges terminates all requirements of AD 90-23-06, AD 91-22-51, and AD 2005- 07-08 for that airplane. The parts installation limitation specified in paragraph (m) of this AD will then prohibit subsequent installation of parts that have not met those requirements. After the compliance times of this AD have passed, we may consider rescinding AD 90-23-06, AD 91- 22-51, and AD 2005-07-08. \n\nRequest To Determine Wedge Type by Physical Inspection \n\n\n\tUPS requested that we revise the terminating action in paragraph (k) of the proposed AD by adding the statement ''or by determining in \n\n((Page 55029))accordance with the Accomplishment Instructions of Boeing SASB 757-57- 0066 R1, Appendices A, B, C, or D (as applicable), that the current wedge installed on the slat is a type B,'' terminates the repetitive inspections required by this AD for this wedge. UPS stated that if the maintenance records are not conclusive, as stated in paragraph (g) of the proposed AD, operators must treat a wedge as a type A and begin repetitive inspections until such time as the intrusive inspections of Boeing SASB 757-57-0066 R1, Appendixes A, B, C, or D, can be accomplished. \n\tWe agree with UPS's request. A physical inspection in accordance with the Accomplishment Instructions of Boeing SASB 757-57-0066 R1, is also a way to determine the wedge type. We have revised paragraph (k) of this AD accordingly. \n\nRequests To Revise Terminating Action \n\n\n\tAAL requested that the terminating action in paragraph (k) of the proposed AD include not only installation of Boeing type B wedges, but also installationof any operator-produced or -modified wedge that includes the corrosion prevention features of the Boeing type B wedge. \n\tDAL requested that the terminating action specified in paragraph (k) of the proposed AD be revised to include any FAA-approved repairs to a slat trailing edge wedge that results in a wedge produced to the same build standards as a type B wedge. \n\tWe do not agree with the commenters' request. The addition of corrosion prevention features on an operator-produced or -modified wedge is not by itself sufficient to make the wedge a type B wedge. Any operator-produced or -modified wedge must pass all checks in Appendix B or C (outboard slats) or Appendix A (inboard slats) of Boeing SASB 757- 57-0066 R1. The operator may request approval of an AMOC by providing data to substantiate that the wedge is produced or modified to the Boeing drawing equivalent to a type B wedge. We have not changed this AD in this regard. \n\nRequest To Resolve Terminating Action InconsistenciesDAL stated that it considers the terminating actions of paragraphs (h) and (j) of AD 2005-07-08, and the terminating actions of the proposed AD to be equivalent. As a result, DAL requested that these inconsistencies be resolved within the AD to substantiate the need for another AD on Model 757-200 airplane slats. \n\tWe partially agree with DAL's request. We agree that paragraph (j) of AD 2005-07-08 and the terminating action of this AD are equivalent. Both are replacement of wedges with type B wedges. We disagree that paragraph (h) in AD 2005-07-08 and the terminating actions of this AD are equivalent. The wedge installed as terminating action in paragraph (h) of AD 2005-07-08 did not have the core that addressed the disbond issue. We have revised paragraph (k) of this AD to include replacement of wedges with type B wedges as specified in Boeing Alert Service Bulletin 757-57A0063, dated June 26, 2003. \n\nRequest To Evaluate Spares Availability \n\n\n\tFedEx requested that spares availability be evaluated prior to AD release to reduce the potential for hardship to the operators. \n\tWe infer that the operator is concerned that there may be an insufficient supply of replacement parts available to operators. Boeing has indicated that there is a supply of new slat wedges available and that operators have rebuilt slat wedges. The need for new replacement parts is further mitigated by the allowance for operators to use serviceable parts. There is also a Boeing part demand intent form in Boeing SASB 757-57-0066 R1 to help Boeing predict the quantity and timing needed for Boeing-supplied parts if operators have a concern that their new part replacement needs may exceed the timely replacement of new parts. Operators concerned about spare parts should proactively provide this information to Boeing. We have not changed this AD in this regard. \n\nEffect of Winglets on Accomplishment of the Proposed Actions \n\n\n\tAviation Partners Boeing stated that installation of winglets per supplemental type certificate (STC) ST01518SE does not affect the actions specified in the NPRM. \n\tWe 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 ST01518SE does not affect the ability to accomplish the actions required by this AD. Therefore, for airplanes on which STC ST01518SE is installed, a ''change in product'' AMOC approval request is not necessary to comply with the requirements of 14 CFR 39.17. \n\nConclusion \n\n\n\tWe 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. We have determined that these minor changes: \n\tAre consistent with the intent that was proposed in the NPRM for correcting the unsafe condition; and \n\tDo not add any additional burden upon the public than was already proposed in the NPRM. \n\tWe 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\tWe reviewed Boeing SASB 757-57-0066 R1. The service information describes procedures for doing inspections on trailing edge slat wedges of the leading edge slats for areas of skin-to-core and aft edge disbonding, and corrective actions including replacement of certain slat wedges. 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. \n\nCosts of Compliance \n\n\n\tWe estimate that this AD will affect 469 airplanes of U.S. registry. We estimate the following costs to comply with this AD: \n\n\n\tEstimated Costs ----------------------------------------------------------------------------------------------------------------Cost on U.S. \n\tAction Labor cost Parts cost Cost per product operators ---------------------------------------------------------------------------------------------------------------- Inspections.................. Up to 24 $0 Up to $2,040 per Up to $956,760 per \n\twork(dash)hours x inspection cycle. inspection cycle. \n\t$85 per hour = \n\t$2,040 per \n\tinspection cycle. ---------------------------------------------------------------------------------------------------------------- \n\n\n\n((Page 55030)) \n\n\n\tWe estimate the following costs to do any necessary replacements that would be required based on the results of the inspections. We have no way of determining the number of aircraft that might need these replacements: \n\n\n\tOn-Condition Costs ---------------------------------------------------------------------------------------------------------------- \n\tActionLabor cost Parts cost Cost per product ---------------------------------------------------------------------------------------------------------------- Wedge replacement (per wedge)...... 43 work-hours x $85 per Up to $84,636......... Up to $88,291. \n\thour = $3,655. ---------------------------------------------------------------------------------------------------------------- \n\n\n\tThe on-condition costs are an estimate of the cost of replacing a type A wedge with a type B wedge, which is a terminating action for the required inspections. There are up to 10 wedge assemblies per airplane, and the price range for a new assembly is $50,923 to $84,636 based on the information provided by Boeing. \n\tThe cost of repairing a type A wedge cannot be estimated because damage type and size may vary widely. \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 the FAA Administrator. Subtitle VII: Aviation Programs, describes in more detail the scope of the Agency's authority. \n\tWe 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. \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 duringthis 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. \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) Is not a ''significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), \n\t(3) Will not affect intrastate aviation in Alaska, and \n\t(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 \n\n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.