AD 2001-18-09

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 777-200 series airplanes, that requires inspections for cracking of the web of the horizontal and sloping pressure decks of the fuselage and certain stiffener splice angles and stiffener end fittings, and repair, if necessary. This amendment also provides an optional preventative modification, which ends the repetitive inspections. The actions specified by this AD are intended to find and fix cracking of the web of the horizontal and sloping pressure decks, which could result in rapid in-flight decompression of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2001-18-09 BOEING: Amendment 39-12435. Docket 2000-NM-334-AD. \n\n\tApplicability: Model 777-200 series airplanes, line numbers 001 through 093 inclusive, certificated in any category. \n\n\tNote 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (e) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTofind and fix cracking of the web of the horizontal and sloping pressure decks, which could result in rapid in-flight decompression of the airplane, accomplish the following: \n\nInitial Inspections \n\n\t(a) Do the inspections in paragraphs (a)(1), (a)(2), and (a)(3) of this AD at the compliance times specified in those paragraphs. Do the inspections according to the Accomplishment Instructions of Boeing Special Attention Service Bulletin 777-53-0004, dated May 11, 2000. \n\n\t\t(1) Area 1: Prior to the accumulation of 16,000 total flight cycles, do an internal high frequency eddy current (HFEC) inspection or an external low frequency eddy current (LFEC) inspection of the horizontal pressure deck web in Inspection Area 1, as defined in the service bulletin. \n\n\t\t(2) Area 2: Prior to the accumulation of 31,000 total flight cycles, do an internal HFEC inspection or an external LFEC inspection of the horizontal pressure deck web, an internal HFEC inspection of the sloping pressure deck, and a detailed visual inspection of the stiffener end fittings at body station (BS) 1245 and the stiffener splice angles at BS 1287, in Inspection Area 2, as defined in the service bulletin. \n\n\tNote 2: For the purposes of this AD, a detailed visual inspection is defined as: "An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required." \n\n\t\t(3) Area 3: Prior to the accumulation of 46,000 total flight cycles, do an internal HFEC inspection or an external LFEC inspection of the horizontal pressure deck web, and an internal HFEC inspection of the sloping pressure deck, in Inspection Area 3, as defined in the service bulletin. \n\nRepetitive Inspections \n\n\t(b) Repeat the inspections in paragraph (a) of this AD at least every 2,500 flight cycles for areas inspected using the HFEC or detailed visual inspection method, or at least every 1,000 flight cycles for areas inspected using the LFEC inspection method, until paragraph (d) of this AD is done. \n\nCorrective Actions \n\n\t(c) If any cracking is found during any inspection required by paragraph (a) or (b) of this AD: Before further flight, repair the affected area according to Boeing Special Attention Service Bulletin 777-53-0004, dated May 11, 2000; except, where the service bulletin says to contact Boeing for repairs, repair per a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or per data meeting the type certification basis of the airplane approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For a repair method to be approved by the Manager, SeattleACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. Repair according to this paragraph ends the repetitive inspections required by paragraph (b) of this AD for the repaired area. \n\nOptional Preventative Modification \n\n\t(d) Modification of Inspection Areas 1, 2, and 3, according to Boeing Special Attention Service Bulletin 777-53-0004, dated May 11, 2000, ends the repetitive inspections required by paragraph (b) of this AD for the modified area. \n\nAlternative Methods of Compliance \n\n\t(e) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, Seattle ACO. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, Seattle ACO. \n\n\tNote 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\nSpecial Flight Permits \n\n\t(f) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished. \n\nIncorporation by Reference \n\n\t(g) With the exception of certain requirements in paragraph (c) of this AD, the actions shall be done in accordance with Boeing Special Attention Service Bulletin 777-53-0004, dated May 11, 2000. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplane Group, P.O. Box 3707, Seattle, Washington 98124-2207. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC. \n\nEffective Date \n\n\t(h) This amendment becomes effective on October 17, 2001.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 777-200 series airplanes was published in the Federal Register on June 27, 2001 (66 FR 34130). That action proposed to require inspections for cracking of the web of the horizontal and sloping pressure decks of the fuselage and certain stiffener splice angles and stiffener end fittings, and repair, if necessary. That action also proposed to provide an optional preventative modification, which ends the repetitive inspections. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 93 Model 777-200 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 27 airplanes of U.S. registry will be affected by this AD, that it will take approximately 36 work hours per airplane to accomplish the required inspections, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $58,320, or $2,160 per airplane, per inspection cycle. \n\n\tThe cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not includeincidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \n\nRegulatory Impact \n\n\tThe regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \n\n\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (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. A final evaluation has been prepared for thisaction and it is contained in the Rules Docket. A copy of it may be obtained from the Rules Docket at the location provided under the caption ADDRESSES. \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, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (14 CFR part 39) as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n\t1. 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\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: