Discussion \n\n\tWe have received a report indicating that during the Model 737-800 series airplanes full-scale fuselage fatigue test, the splice fitting failed prior to the design service objective. Additionally, we have received a report indicating that a cracked splice fitting was found on an airplane with less than 13,500 total flight cycles. This condition, if not corrected, could result in cracking of the existing fitting that may cause cracking through the skin and consequent decompression of the flight cabin. \n\nRelevant Service Information \n\n\tWe have reviewed Boeing Alert Service Bulletin (ASB) 737-53A1222, Revision 2, dated October 20, 2005. The ASB describes procedures for replacing the splice fitting between windows number 1 and 2, at point "D" on the windowsill with a new splice fitting, and performing related investigative actions. Those investigative actions include performing an open hole eddy current inspection for cracking of the fastener holes, and a special detailed inspection for cracking of 12 fasteners in the adjacent structure. The ASB also describes procedures for repetitive external detailed inspections of the skin near the six skin fasteners below the splice fitting. The ASB specifies that if cracking is detected, to contact Boeing for further instructions. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. \n\nFAA's Determination and Requirements of This AD \n\n\tThe unsafe condition described previously is likely to exist or develop on other airplanes of the same type design. For this reason, we are issuing this AD to prevent cracking of the existing fitting that may result in cracking through the skin and consequent decompression of the flight cabin. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and the ASB." \n\nDifferences Between the AD and the ASB \n\n\tWhere the ASB specifies contacting Boeing if any cracking is detected, this AD requires that, repair of any cracking be accomplished before further flight, in accordance with a method approved by the Manager, Seattle Aircraft Certification Office (ACO). \n\n\tAlthough the ASB specifies performing repetitive external detailed inspections of the skin near the six skin fasteners below the splice fitting, this AD does not require those inspections. These differences have been coordinated with the manufacturer. \n\nInterim Action \n\n\tWe consider this AD to be an interim action. We are currently considering requiring repetitive external detailed inspections for cracking of the skin near the six skin fasteners below the splice fitting. However the planned compliance time for accomplishing those inspections would necessitate allowing enough time to provide notice and opportunity for prior public comment on the merits of requiring those inspections. \n\nSimilar ModelsThe splice fitting between windows number 1 and 2, at point "D" on the windowsill, on certain Boeing Model 737-600, -700, -700C series airplanes is identical to the splice fitting on the affected Model 737- 800 series airplanes. Therefore, all of these models may be subject to the same unsafe condition. \n\nFAA's Determination of the Effective Date \n\n\tSince an unsafe condition exists that requires the immediate adoption of this AD, we have found that notice and opportunity for public comment before issuing this AD are impracticable, and that good cause exists to make this AD effective in less than 30 days. \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-2005- 23176; Directorate Identifier 2005-NM-220-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 Dockets \n\n\tYou may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the DocketManagement Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647- 5227) is located on the plaza level of the Nassif 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\tFor the reasons discussed above, I certify that the regulation: \n\n\t1. Is not a "significant regulatory action" under Executive Order 12866; \n\n\t2. Is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\n\t3. Will not have a significant economic impact, positive or negative, on a substantial number of small entities under thecriteria of the Regulatory Flexibility Act. \n\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation. \n\nList of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, 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 Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):