AD 2007-18-52 SUPERSEDED

This document publishes in the Federal Register an amendment adopting airworthiness directive (AD) 2007-18-52 that was sent previously to all known U.S. owners and operators of Boeing Model 737- 600, -700, -700C, -800, -900, and -900ER series airplanes by individual notices. This AD requires repetitive detailed inspections of the slat track downstop assemblies to verify that proper hardware is installed, one-time torquing of the nut and bolt, and corrective actions if necessary. This AD is prompted by reports of parts coming off the main slat track downstop assemblies. We are issuing this AD to detect and correct loose or missing parts from the main slat track downstop assemblies, which could result in a fuel leak and consequent fire.

Final rule; request for comments.

2007-18-52 Boeing: Amendment 39-15197. Docket No. FAA-2007-29089; Directorate Identifier 2007-NM-215-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective September 26, 2007, to all persons except those persons to whom it was made immediately effective by emergency AD 2007-18-52, issued on August 28, 2007, which contained the requirements of this amendment. \n\nAffected ADs \n\n\t(b) This AD supersedes emergency AD 2007-18-51, issued August 25, 2007. \n\nApplicability \n\n\t(c) This AD applies to all Boeing Model 737-600, -700, -700C, - 800, -900, and -900ER series airplanes, certificated in any category. \n\nUnsafe Condition \n\n\t(d) This AD results from additional reports of parts coming off the main slat track downstop assemblies. We are issuing this AD to detect and correct loose or missing parts from the main slat track downstop assemblies, which could result in a fuel leak and consequent fire. \n\nCompliance \n\n\t(e) You are responsible for having the actions required by thisAD performed within the compliance times specified, unless the actions have already been done. \n\n\tNote 1: Paragraph (f) of this AD merely restates the requirements of paragraph (f)(1) of AD 2007-18-51. As allowed by the phrase, "unless the actions have already been done,'' if the applicable initial inspections required by paragraph (f)(1) of AD 2007-18-51 have already been done, this AD does not require that those inspections be repeated until the repetitive interval of 3,000 flight cycles. \n\nRepetitive Detailed Inspections: New Initial Compliance Time \n\n\t(f) Within 10 days after the effective date of this AD: Do a detailed inspection or a borescope inspection of each main slat track downstop assembly to verify proper installation of the slat track hardware (i.e., the bolt, washers, downstops, stop location, and nut shown in Figure 1 of Boeing Service Letter 737-SL-57-084-B, dated July 10, 2007, and in this AD). Proper installation of the sleeve need not be confirmed, and the stop location part may be installed on either the inboard or the outboard side of the slat track. If any part is missing or is installed improperly, before further flight, install a new or serviceable part using a method approved in accordance with the procedures specified in paragraph (h) of this AD; and do a detailed inspection of the inside of the slat can for foreign object debris (FOD) and damage. Before further flight, remove any FOD found and repair any damage found using a method approved in accordance with the procedures specified in paragraph (h) of this AD. Using Boeing Multi Operator Message Number 1-523812011-1, issued August 25, 2007; or 1-527463441-1, issued August 28, 2007; is one approved method for verifying proper installation; installing a new or serviceable part; and inspecting for damage and FOD, and removing FOD and repairing damage. Repeat the actions required by paragraph (f) of this AD thereafter at intervals not to exceed 3,000 flight cycles. \n\n\tNote 2: Paragraph (g) of this AD merely restates the requirements of paragraph (f)(2) of AD 2007-18-51. As allowed by the phrase, "unless the actions have already been done,'' if the torque application required by paragraph (f)(2) of AD 2007-18-51 has already been done, this AD does not require that the torque application be repeated. \n\nOne-Time Torquing \n\n\t(g) Within 24 days after receipt of AD 2007-18-51: Apply a torque between 50 to 80 inch-pounds to the nut. The bolt head must be held with the torque applied to the nut. \n\n\tNote 3: For the purposes of this AD, a detailed inspection is: "An intensive examination of a specific item, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at an intensity deemed appropriate. Inspection aids such as mirror, magnifying lenses, etc., may be necessary. Surface cleaning and elaborate procedures may be required.'' \n\n\n\nAlternative Methods of Compliance(AMOCs) \n\n\t(h)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \n\n\t(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your appropriate principal inspector (PI) in the FAA Flight Standards District Office (FSDO), or lacking a PI, your local FSDO. \n\n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane, and the approval must specifically refer to this AD. \n\n\t(4) AMOCs approved previously in accordance with AD 2007-18-51 are approved as AMOCs for the corresponding provisions of this AD. \n\nMaterial Incorporated by Reference \n\n\t(i) None.

On August 28, 2007, we issued emergency AD 2007-18-52, which applies to all Boeing Model 737-600, -700, -700C, - 800, -900, and -900ER series airplanes. That emergency AD superseded emergency AD 2007-18-51, described below. \n\nBackground \n\n\tOn August 25, 2007, we issued emergency AD 2007-18-51 for all Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. That AD requires repetitive detailed inspections of the main slat track downstop assemblies to verify that proper hardware is installed, one-time torquing of the nut and bolt, and corrective actions if necessary. Corrective actions include installing a new or serviceable part; and doing a detailed inspection of the inside of the slat can for foreign object debris (FOD) and damage, and removing any FOD and repairing damage that is found. \n\n\tThat AD resulted from reports of parts of the main slat track downstop assembly coming off the main slat track. In one case, a nut fell into theslat track housing (referred to as "slat can'') and, during a subsequent slat retraction, the track made contact with the nut, pushing it into the wall of the can and puncturing it. That operator reported finding fuel leaking from the drain hole in the slat track housing at the No. 5 slat track position. In another case, an initial investigation revealed that following retraction of the slats after landing on a Model 737-800 airplane, loose parts of the main slat track downstop assembly punctured the slat can, which resulted in a fuel leak and a fire that ultimately destroyed the airplane. We issued that AD to detect and correct loose or missing parts from the main slat track downstop assemblies, which could result in a fuel leak and consequent fire. \n\nActions Since Issuance of Emergency AD 2007-18-51 \n\n\tSince the issuance of emergency AD 2007-18-51, we have received additional reports of parts coming off the main slat track downstop assemblies. In these cases, the parts were foundin the bottom of the slat track housing ("slat can''). Additionally, in one case, the slat can was damaged. \n\n\tBased on this new information, we find that the 24-day compliance time specified in emergency AD 2007-18-51 for accomplishing the detailed inspection of each main slat track downstop assembly to verify proper installation of the slat track hardware is not adequate to address the unsafe condition. We have determined that the appropriate compliance time for this inspection is 10 days after receipt of emergency AD 2007-18-52. In addition, we have determined that an inspection using borescope techniques in lieu of a detailed inspection is acceptable. \n\n\tFurther, we have determined that by performing the initial detailed or borescope inspection within the reduced compliance time of 10 days, the compliance time for torquing the nut and bolt can remain at 24 days after receipt of emergency AD 2007-18-51. \n\nFAA's Determination and Requirements of This AD \n\n\tSince the unsafe condition described is likely to exist or develop on other airplanes of the same type design, we issued emergency AD 2007-18-52 to detect and correct loose or missing parts from the main slat track downstop assemblies, which could result in a fuel leak and consequent fire. \n\n\tThis AD supersedes emergency AD 2007-18-51, which required repetitive detailed inspections of the main slat track downstop assemblies to verify that proper hardware is installed, one-time torquing of the nut and bolt, and corrective actions if necessary. Corrective actions include installing a new or serviceable part; and doing a detailed inspection of the inside of the slat can for foreign object debris (FOD) and damage, and removing any FOD and repairing damage that is found. \n\n\tThis AD continues to require the same actions as emergency AD 2007- 18-51, but reduces the compliance time for the initial detailed inspection of each main slat track downstop assembly to verify proper installation of the slat track hardware from 24 days after receipt of emergency AD 2007-18-51 to 10 days after receipt of this new AD. This AD also provides an additional inspection method (using borescope techniques) in lieu of the detailed inspection. \n\nClarification of Determining Proper Installation of Hardware \n\n\tOperators should note that it was not our intent that the hardware for the main slat track downstop assemblies be disassembled to determine proper installation of the sleeve. Proper installation of the sleeve need not be confirmed, and the stop location part may be installed on either the inboard or the outboard side of the slat track. Disassembling the parts provides additional opportunities for introducing the unsafe condition addressed in this AD. Therefore, we have revised paragraph (f) of this AD accordingly. \n\nClarification of Reference to Boeing Multi Operator Message \n\n\tParagraph (f)(1) of emergency AD 2007-18-51 identified "Boeing Correspondence (Multi Operator Message) Service RequestID 1-523812011, issued August 25, 2007,'' as one approved method for verifying proper installation; installing a new or serviceable part; and inspecting for damage and FOD, and removing FOD and repairing damage. This AD identifies that document correctly as "Boeing Multi Operator Message Number 1-523812011-1, issued August 25, 2007.'' \n\n\tSince the issuance of emergency AD 2007-18-51, Boeing has issued Boeing Multi Operator Message Number 1-527463441-1, issued August 28, 2007. We have referenced that document in this AD as an additional approved method for doing the specified actions. \n\n\tWe found that immediate corrective action was required; therefore, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual notices issued on August 28, 2007, to all known U.S. owners and operators of Boeing Model 737-600, -700, -700C, -800, -900, and -900ER series airplanes. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons. \n\nInterim Action \n\n\tWe consider this AD interim action. If final action is later identified, we might consider further rulemaking then. \n\nComments Invited \n\n\tThis AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2007- 29089, Directorate Identifier 2007-NM-215-AD,'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it. \n\n\tWe will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov. \n\nExamining the Docket \n\n\tYou may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Operations office (telephone (800) 647-5527) is located on the ground level of the West Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them. \n\nAuthority for This Rulemaking \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\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\nRegulatory Findings \n\n\tWe have determined that 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. \n\n\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action'' under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If this emergency regulation is later deemed significant under DOT Regulatory Policies and Procedures, we will prepare a final regulatory evaluation and place it in the AD Docket. See the ADDRESSES section for a location to examine the regulatory evaluation, if filed. \n\nList of Subjects in14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Safety. \n\nAdoption of the Amendment \n\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. The authority citation for part 39 continues to read as follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive (AD):

Use one of the following addresses to submit comments on this AD.\n\n\tDOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically. \n\tGovernment-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically. \n\tMail: U.S. Department of Transportation, Docket Operations, M-30, West Building Ground Floor, Room W12-140, 1200 New Jersey Avenue, SE., Washington, DC 20590. \n\tFax: (202) 493-2251. \n\tHand Delivery: Room W12-140 on the ground floor of the West Building, 1200 New Jersey Avenue, SE., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. \n\tContact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for service information identified in this AD.

Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle Aircraft Certification Office, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone (425) 917-6440; fax (425) 917-6590.