Discussion \n\n\tWe previously issued AD 2004-22-24, amendment 39-13852 (69 FR 64835, November 9, 2004), for all Boeing Model 707 and 720 series airplanes. That AD requires repetitive detailed and high frequency eddy current inspections for corrosion, signs of corrosion (e.g., blistering or signs of fuel leaks), and cracking, and certain related follow-on and investigative actions if necessary. That AD resulted from a report of a 31-inch crack found during a routine inspection. We issued that AD to find and fix corrosion and stress corrosion cracking of the upper and lower chords on the wing front and rear spars, which could result in reduced structural integrity of the wing. \n\n\tSince we issued that AD, Boeing has informed us that, for Model 720 and 720B series airplanes, the repetitive inspections required by AD 2004-22-24 do not adequately address the identified unsafe condition. The wing configuration of Model 720 and 720B series airplanes differs from that on Model 707 series airplanes. Model 720 series airplanes have an aerodynamic fairing that extends from the aircraft side of body to the inboard nacelle. This fairing prevents operators from doing the repetitive inspections intended by AD 2004-22-24. Cracks, corrosion, or signs of damage (e.g., finish scratches, blistering or signs of fuel leaking) of the front spar upper chords under the fairing web, if not detected and corrected, could result in structural failure of the wing. \n\nRelevant Service Information \n\n\tWe have reviewed Boeing Multi-Operator Message (MOM) 1-151636045-1, dated January 17, 2006. The MOM describes procedures for doing repetitive detailed and high-frequency eddy current (HFEC) inspections for any crack, corrosion, or scratch of the front spar upper chords under the fairing web, and repair if necessary. The HFEC inspection is in the area of the forward face of the vertical flange, from the side of the body to the inboard nacelle (front spar station 107 through 383), from the upper fastener row to the upper edge of the chord flange, and the surface in between. The detailed inspection is of the forward face of the vertical flange from the upper edge of the chord flange to the lower edge of the chord flange. 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 detect and correct any crack, corrosion, or sign damage (e.g., finish scratches, blistering, or signs of fuel leaking) of the front spar upper chords under the fairing web, which could result in structural failure of the wing. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Differences Between the AD and the MOM." \n\nDifferences Between the AD and the MOM \n\n\tAlthough the MOM specifies to contact the manufacturer for repair instructions, this proposed AD would require operators to do the repair using a method we approve. \n\n\tThe MOM also specifies to contact the manufacturer for instructions on oversizing fasteners during restoration, but this proposed AD would require oversizing the fasteners in one of the following ways: \n\t\nUsing a method that we approve; or \n\t\nUsing data that meet the certification basis of the airplane, and that have been approved by an Authorized Representative for the Boeing Commercial \nAirplanes Delegation Option Authorization Organization whom we have authorized to make those findings. \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-2006- 24162; Directorate Identifier 2006-NM-031-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 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 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.For 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 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\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):