AD 2008-04-11

The FAA is adopting a new airworthiness directive (AD) for all Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. This AD requires revising the FAA-approved maintenance program by incorporating new airworthiness limitations (AWLs) for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. This AD also requires the initial performance of certain repetitive AWL inspections to phase in those inspections, and repair if necessary. This AD results from a design review of the fuel tank systems. We are issuing this AD to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs, or maintenance actions, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

Final rule.

2008-04-11 Boeing: Amendment 39-15383. Docket No. FAA-2007-28381; Directorate Identifier 2006-NM-164-AD. \n\nEffective Date \n\n\t(a) This AD becomes effective March 28, 2008. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to all Boeing Model 707-100 long body, -200, -100B long body, and -100B short body series airplanes; Model 707- 300, -300B, -300C, and -400 series airplanes; and Model 720 and 720B series airplanes; certificated in any category. \n\n\tNote 1: This AD requires revisions to certain operator maintenance documents to include new inspections. Compliance with these inspections is required by 14 CFR 91.403(c). For airplanes that have been previously modified, altered, or repaired in the areas addressed by these limitations, the operator may not be able to accomplish the actions described in the revisions. In this situation, to comply with 14 CFR 91.403(c), the operator must request approval for an alternative method of compliance according to paragraph (i) of this AD. The request should include a description of changes to the required inspections that will ensure the continued operational safety of the airplane. \n\nUnsafe Condition \n\n\t(d) This AD results from a design review of the fuel tank systems. We are issuing this AD to prevent the potential for ignition sources inside fuel tanks caused by latent failures, alterations, repairs, or maintenance actions, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane. \n\nCompliance \n\n\t(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done. \n\nService Information \n\n\t(f) The term "D6-7552-AWL March 2006,'' as used in this AD, means Boeing 707/720 Airworthiness Limitations (AWLs) Document D6- 7552-AWL, dated March 2006. \n\nRevision of AWLs Section \n\n\t(g) Before December 16, 2008, revise the FAA-approved maintenance program by incorporating the information in the sections specified in paragraphs (g)(1) through (g)(3) of this AD, except that the initial inspection specified in paragraph (h) of this AD must be done at the time specified in paragraph (h). Accomplishing the revision in accordance with a later revision of D6-7552-AWL March 2006 is an acceptable method of compliance if the revision is approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA. \n\t(1) Section B., "FUEL SYSTEMS AIRWORTHINESS LIMITATIONS,'' of D6-7552-AWL March 2006. \n\t(2) Section C., "SYSTEM AWL PAGE FORMAT,'' of D6-7552-AWL March 2006. \n\t(3) Section D., "AIRWORTHINESS LIMITATIONS--FUEL SYSTEMS,'' of D6-7552-AWL March 2006. \n\nInitial Inspection and Repair if Necessary \n\n\t(h) At the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD: Do a detailed inspection of external wires over the center fuel tank for damaged or loose clamps, wire chafing, and wire bundles in contactwith the surface of the center fuel tank, in accordance with Section D, "AIRWORTHINESS LIMITATIONS--FUEL SYSTEMS,'' AWL 28-AWL-01, of D6-7552-AWL March 2006. If any discrepancy is found during this inspection, repair the discrepancy before further flight in accordance with D6-7552-AWL March 2006. Accomplishing the actions required by this paragraph in accordance with a later revision of D6-7552-AWL March 2006 is an acceptable method of compliance if the revision is approved by the Manager, Seattle ACO. Accomplishing AWL 28-AWL-01 as part of an FAA-approved maintenance program prior to the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD constitutes compliance with the requirements of this paragraph. \n\t(1) Before the accumulation of 36,000 total flight cycles, or within 120 months since the date of issuance of the original standard airworthiness certificate or the date of issuance of the original export certificate of airworthiness, whichever occurs first. \n\t(2)Within 72 months after the effective date of this AD. \n\n\tNote 2: 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\nNo Alternative Inspections, Inspection Intervals, or CDCCLs \n\n\t(i) After accomplishing the actions specified in paragraphs (g) and (h) of this AD, no alternative inspections, inspection intervals, or CDCCLs may be used unless the inspections, intervals, or CDCCLs are part of a later revision of D6-7552-AWL March 2006, that is approved by the Manager, Seattle ACO; or unless the inspections, intervals, or CDCCLs are approved as an alternative method of compliance (AMOC) in accordance with the procedures specified in paragraph (j) of this AD. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(j)(1) The Manager, Seattle ACO, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19. \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\nMaterial Incorporated by Reference \n\n\t(k) You must use Boeing 707/720 Airworthiness Limitations (AWLs) Document D6-7552-AWL, including attachment, dated March 2006, to perform the actions that are required by this AD, unless the AD specifies otherwise. (Only the first page of the attachment contains the document date; no other page of the attachment contains this information.) The Director of the Federal Register approved the incorporation by reference of this document in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Contact Boeing Commercial Airplanes, P.O. Box 3707, Seattle, Washington 98124-2207, for a copy of this service information. You may review copies at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http://www.archives.gov/federal- register/cfr/ibr-locations.html.

Discussion \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 Boeing Model 707 airplanes, and Model 720 and 720B series airplanes. That NPRM was published in the Federal Register on July 3, 2007 (72 FR 36370). That NPRM proposed to require revising the FAA-approved maintenance program by incorporating new airworthiness limitations (AWLs) for fuel tank systems to satisfy Special Federal Aviation Regulation No. 88 requirements. That NPRM also proposed to require the initial performance of certain repetitive AWL inspections to phase in those inspections, and repair if necessary. \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\nChanges Made to This AD \n\n\tFor standardization purposes, we have revised this AD in the following ways: \n\tWe have added a new paragraph (i) to this AD to specifythat no alternative inspections, inspection intervals, or critical design configuration control limitations (CDCCLs) may be used unless they are part of a later approved revision of Boeing 707/720 Airworthiness Limitations (AWLs) Document D6-7552-AWL, dated March 2006, or unless they are approved as an alternative method of compliance (AMOC). Inclusion of this paragraph in the AD is intended to ensure that the AD-mandated airworthiness limitations changes are treated the same as the airworthiness limitations issued with the original type certificate. \n\tWe have simplified the language in Note 1 of this AD to clarify that an operator must request approval for an AMOC if an operator cannot accomplish the required inspections because an airplane has been previously modified, altered, or repaired in the areas addressed by the required inspections. \n\nRequest To Change Wording in Note 1 of the NPRM \n\n\tBoeing requests that we change the wording in Note 1 of the NPRM as follows: \n\tChange"new inspections and maintenance actions'' to include the words "according to paragraph (g)'' after "actions.'' \n\tChange "the operator must request approval for revision to the airworthiness limitations'' to "the operator must request approval for deviation from the airworthiness limitations.'' \n\tRemove "as applicable'' from the last sentence of the note and change the paragraph reference from "paragraph (g) or (i)'' to "paragraph (i).'' \n\tBoeing explains that the current wording is difficult to follow. \n\tAs stated previously, we have simplified the language in Note 1 of this AD for standardization with other similar ADs. The language the commenter requests we change does not appear in the revised note; therefore, no additional change to this AD is necessary in this regard. \n\nCredit for Prior Accomplishment of AWL 28-AWL-01 \n\n\tWe have added a statement to paragraph (h) of this AD specifying that accomplishment of AWL 28-AWL-01 as part of an FAA-approved maintenance program prior to the later of the times specified in paragraphs (h)(1) and (h)(2) of this AD constitutes compliance with the requirements of paragraph (h). \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 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 213 airplanes of the affected design in the worldwide fleet. This AD affects about 76 airplanes of U.S. registry. The required actions take about 8 work hours 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 $48,640, or $640 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\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\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866; \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \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\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):