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 all McDonnell Douglas Model MD-11 and -11F airplanes. That NPRM was published in the Federal Register on September 20, 2006 (71 FR 54941). That NPRM proposed to require revising the maintenance inspection program that provides for inspection of principal structural elements (PSEs) and replacement of safe-life parts, to incorporate a new revision to the MD-11 Airworthiness Limitations Instructions (ALI). The revision would reduce inspection intervals for fatigue cracking of certain PSEs, and expand the inspection area for a certain other PSE. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comment received. \n\nRequest To Extend Certain Initial Inspection Thresholds \n\n\tBoeing has requested that we provide an extension of the initial inspection threshold for certain airplanes. Boeing states that the ALI specified in the NPRM would require reducing the initial inspection threshold for PSE 54.52.01.1 from 19,000 total flight cycles to 10,200 total flight cycles. Boeing adds that for PSEs 54.21.01.1 (54.52.01.1), 57.21.02.1, and 57.23.01.1, a minimum of 24 months is required to accomplish the initial inspection after paragraph (f) of the NPRM is done; the initial inspection times for these PSEs were reduced. Boeing also states that, as of July 2006, there are approximately 50 airplanes exceeding 10,000 total flightcycles. Boeing points out that the ALI would reduce the initial inspection threshold for PSEs 57.21.02.1 and 57.23.01.1 from 19,900 total flight cycles to 15,750 and 15,250 total flight cycles respectively. Boeing notes that, as of July 2006, there are six airplanes with more than 12,000 total flight cycles. Additionally, Boeing points out that the ALI would reduce the repetitive inspection interval for PSE 57.21.05.1 from 10,000 flight cycles to 3,200 flight cycles. Approximately 50 airplanes would have already accomplished the inspection, but would be planning for a 10,000-flight-cycle repetitive interval instead of a 3,200-flight-cycle repetitive interval. Boeing asserts that a substantial increase in the compliance time requirements for those PSE inspections is necessary to prevent an immediate hardship on the operators of these airplanes. \n\n\tFor the reasons cited by Boeing, we agree with its request to extend certain inspection compliance times. We have determined that PSE number 54.21.01.1, as cited in Boeing's comment, is a typographical error and we have used the correct PSE number, 54.52.01.1, in this AD. We have added a new paragraph (h) to this AD to specify those certain PSE inspection compliance times, and re-identified the remaining paragraphs accordingly. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the change described previously. 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 102 airplanes of the affected design in the worldwide fleet. This AD affects about 93 airplanes of U.S. registry. The maintenance and inspection program revision takes about 1 work hour per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the AD for U.S. operators is $7,440, or $80 perairplane, per inspection cycle. \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) Is not 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, 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):