AD 2001-14-22

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 747-100 and -200 series airplanes, that requires repetitive inspections for cracking of the station 800 frame assembly, and repair, if necessary. The actions specified by this AD are intended to find and fix fatigue cracks that could extend and fully sever the frame, which could result in development of skin cracks that could lead to rapid depressurization of the airplane. This action is intended to address the identified unsafe condition.

Final rule.

2001-14-22 Boeing: Amendment 39-12333. Docket 2000-NM-346-AD. \n\n\tApplicability: Model 747-100 and -200 series airplanes, as listed in Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 2000, certificated in any category.\n\n\tNote 1: This AD applies to each airplane identified in the preceding applicability \nprovision, 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 (d) 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\tTo find and fix fatigue cracks of the station 800 frame assembly that could extend and fully sever the frame, which could result in development of skin cracks that could lead to rapid depressurization of the airplane, accomplish the following: \n\nRepetitive Inspections \n\n\t(a) Do detailed visual, surface high frequency eddy current (HFEC), and open hole HFEC inspections, as applicable, for cracking of the station 800 frame assembly (including the inner chord strap, angles, and exposed web) between stringers 14 and 18, according to Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 2000. Except as provided by paragraph (b) of this AD, do the inspection at the applicable time specified in Table 1 below, and repeat the inspections thereafter at least every 3,000 flight cycles: Table 1 is as follows: \n\n\nTable 1.--Compliance Times \n\nTotal flight cycles as of the effective date of thisAD \nDo the inspection in paragraph (a) at this time \n(1) Fewer than 19,000\nBefore the accumulation of 19,000 total flight cycles, or \nwithin 1,500 flight cycles after the effective date of \nthis AD, whichever comes later.\n(2) 19,000 or more but 24,250 or fewer.\nWithin 1,500 flight cycles or 12 months after the effective \ndate of this AD, whichever comes first.\n(3) 24,251 or more\nWithin 750 flight cycles or 12 months after the effective \ndate of this AD, whichever comes first.\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\nAdjustments to Compliance Time: Cabin Differential Pressure \n\n\t(b) For the purposes of calculating the compliance threshold and repetitive interval for the actions required by paragraph (a) of this AD, the number of flight cycles in which cabin differential pressure is at 2.0 pounds per square inch (psi) or less need not be counted when determining the number of flight cycles that have occurred on the airplane, provided that flight cycles with momentary spikes in cabin differential pressure above 2.0 psi are included as full pressure cycles. For this provision to apply, all cabin pressure records must be maintained for each airplane: NO fleet-averaging of cabin pressure is allowed. \n\nRepair \n\n\t(c) If any cracking is detected during any inspection required by paragraph (a) of this AD, before further flight, repair the cracking according to a method approved by the Manager, Seattle Aircraft Certification Office (ACO), FAA; or according to 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, Seattle ACO, as required by this paragraph, the approval letter must specifically reference this AD. \n\nAlternative Methods of Compliance \n\n\t(d) 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(e) 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(f) Except as provided by paragraphs (b) and (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 747-53A2451, including Appendix A, dated October 5, 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(g) This amendment becomes effective on August 30, 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 747-100 and -200 series airplanes was published in the Federal Register on April 19, 2001 (66 FR 20114). That action proposed to require repetitive inspections for cracking of the station 800 frame assembly, and repair, if necessary. \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\tThe 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 258 airplanes of the affected design in the worldwide fleet. The FAA estimates that 139 airplanes of U.S. registry will be affected by this AD, that it will take up to 14work hours per airplane to accomplish the required inspection, 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 as much as $116,760, or $840 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 include incidental 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 this action 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\nAdoptionof 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: