Examining the Docket \n\n\tYou may examine the airworthiness directive (AD) docket on the Internet at http://dms.dot.gov or in person at the Docket Management 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 street address stated in the ADDRESSES section. \n\nDiscussion \n\n\tThe FAA issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to certain Boeing Model 737-100, -200, -200C, -300, -400, -500, -600, -700, -700C, -800 and - 900 series airplanes. That NPRM was published in the Federal Register on July 5, 2005 (70 FR 38630). That NPRM proposed to require modifying the elevator input torque tube assembly. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments received. \n\nSupport for the Proposed AD \n\n\tOne commenter states that although the proposed AD does not affect any airplane in its fleet, it supports the actions in the AD. \n\nRequest To Clarify Summary \n\n\tThe airplane manufacturer requests that we revise the third sentence in the Summary section of the proposed AD from, "This proposed AD is prompted by a report of a restriction in the pilot's elevator control system," to "This proposed AD is prompted by the results of a design review performed on the input torque tube assembly, which discovered possible failure modes that could lead to a jam of the elevator control system." The commenter explains that the sentence, as proposed, may be misleading by connecting the pilots' reported condition to the hypothetical jam that is addressed by the proposed AD. \n\n\tWe partially agree with the commenter. We agree that the wording in the Summary section could lead to an interpretation that the cause of the reported incident was restrictions inthe pilot's elevator input control system. We disagree with revising the section as proposed, because, as stated in the Discussion section of the proposed AD, the design review was conducted as part of an intensive investigation. The investigation was conducted by the National Transportation Safety Board, the FAA, and Boeing. We have revised the Summary section and paragraph (d) of the final rule to state, "This AD results from a report of a restriction in the pilot's elevator input control system. A design review performed on the elevator input torque tube assembly in the course of the investigation discovered possible failure modes that could lead to a jam of the elevator control system." \n\nRequest To Allow Different Procedures for Re-Identification \n\n\tThe commenter, an airplane operator, requests that paragraph (f) be revised to allow alternate methods for re-identifying the modified elevator torque tube assemblies. The commenter explains that the service bulletins referenced inthe proposed AD specify the use of a rubber ink stamp method to re-identify the modified assemblies. The commenter points out that operators of a single airplane would have to fabricate or acquire a stamp for a one-time use, and operators of many airplanes would have to acquire dozens of rubber stamps to support the various overhaul facility locations. The commenter requests that the final rule allow for use of either the rubber stamp method, or the use of a pen with indelible ink. The commenter states that the component number could then be covered with protective covering. \n\n\tWe agree with the commenter. The intent of the procedures in the proposed AD and in the service bulletins is to signify that the modification has been accomplished, not to specify the method of re- identification. We have revised paragraph (f) of the final rule to allow alternate permanent part marking in lieu of rubber stamping. \n\nClarification of Alternative Method of Compliance (AMOC) Paragraph \n\n\tWe have revised this action to clarify the appropriate procedure for notifying the principal inspector before using any approved AMOC on any airplane to which the AMOC applies. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCosts of Compliance \n\n\tThere are about 2,971 airplanes of the affected design in the worldwide fleet. This AD will affect about 1,573 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs \n\n\nModification \nWork hours \nAverage labor rate per hour \nParts \nCost per airplane \nU.S. registered airplanes \nFleet cost \n\n\n\n\n\n\n\n\n\n\n\n\n\n\nFor airplanes identified in Boeing Alert \nService Bulletin 737-27A1271 as \nGroup 1 \n5 \n$65 \n$701 \n$1,026 \n249 \n$255,474 \n\n\n\n\n\n\n\n\n\n\n\n\n\n\nFor airplanes identified in Boeing Alert \nService Bulletin 737-27A1271 as \nGroup 2 \n7 \n65 \n1,290 \n1,745 \n311 \n542,695 \n\n\n\n\n\n\n\nFor all airplanes identified in Boeing Alert \nService Bulletin 737-27A1274 \n3 \n65 \n50 \n245 \n1,013 \n248,185 \n\n\tIn addition, a special tool is necessary to do the modification required by this AD. Boeing will provide one tool at no charge to each customer regardless of warranty status. \n\n\tBased on these figures, the estimated total cost of this AD for U.S. operators is about $1,046,354, or between $1,271 and $1,990 per airplane. \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 this AD: \n\n\t(1) Isnot a "significant regulatory action" under Executive Order 12866; \n\n\t(2) Is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and\n \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\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\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\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):