AD 99-19-29

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 767 series airplanes, that requires repetitive inspections of certain H-11 tension bolts at each side-of-body kick-load fitting and on the lower splice plate (both located on the wing rear spar) to detect damaged or broken bolts; and follow-on actions, if necessary. This amendment also requires eventual replacement of the existing bolts with new, improved bolts, which constitutes terminating action for the repetitive inspections. This amendment is prompted by a report that an operator found two broken H-11 tension bolts on the side-of-body kick-load fitting on one airplane. The actions specified by this AD are intended to prevent cracking of the bolts due to stress corrosion, which could result in reduced structural integrity of the wing-to-body joint structure.

Final rule

99-19-29 BOEING: Amendment 39-11316. Docket 98-NM-278-AD.\n\n\tApplicability: Model 767 series airplanes, line positions 1 through 177 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 (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\tToprevent cracking of the H-11 tension bolts on the side-of-body kick-load fitting due to stress corrosion, which could result in reduced structural integrity of the wing-to-body joint structure, accomplish the following: \n\n\t(a)\tWithin 90 days after the effective date of this AD: Perform a detailed visual inspection of the four H-11 tension bolts at each side-of-body kick-load fitting located on the wing rear spar to detect damaged or broken bolts; and accomplish the requirements in either paragraph (a)(1) or (a)(2) of this AD, in accordance with the Accomplishment Instructions of Boeing Service Bulletin 767-57A0064, Revision 1, dated July 9, 1998. \n\n\t\t(1)\tOption 1: Repeat the detailed visual inspection of the bolts at each side-of-body kick-load fitting thereafter at intervals not to exceed 90 days, until accomplishment of the actions specified in paragraph (c) of this AD. Or \n\n\t\t(2)\tOption 2: Perform a detailed visual inspection of the four H-11 tension bolts on the lower splice plate located on the wing rear spar to detect damaged or broken bolts. Repeat the detailed inspection of each side-of-body kick-load fitting and the lower splice plate thereafter at intervals not to exceed 18 months, until accomplishment of the actions specified in paragraph (c) of this AD. \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(b)\tIf evidence of any damaged or broken bolt is detected, prior to further flight, replace the discrepant bolt with a new, improved bolt in accordance with Boeing Service Bulletin 767-57A0064, Revision 1, dated July 9, 1998. Thereafter, repeat the detailed inspection in either paragraph (a)(1) or (a)(2) of this AD, as applicable, until accomplishment of the actions specified in paragraph (c) of this AD. \n\n\t(c)\tWithin 9,000 flight cycles or 48 months after the effective date of this AD, whichever occurs first, replace all four H-11 tension bolts at each side-of-body kick-load fitting with new, improved bolts, and perform a detailed visual inspection to detect any damaged or broken bolt of the lower splice plate located on the wing rear spar, in accordance with Boeing Service Bulletin 767-57A0064, Revision 1, dated July 9, 1998. If any damaged or broken bolt is detected during the inspection, prior to further flight, replace the discrepant bolt with a new, improved bolt in accordance with Boeing Service Bulletin 767-57A0064, Revision 1, dated July 9, 1998. Accomplishment of the actions specified in this paragraph constitutes terminating action for the repetitive inspection requirements of this AD. \n\nAlternative Methods of Compliance \n\n\t(d)\tAn 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 Aircraft Certification Office (ACO), FAA, Transport Airplane Directorate. 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)\tSpecial 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)\tThe inspections and replacements shall be done in accordance with Boeing Service Bulletin 767-57A0064, Revision 1, dated July 9, 1998. 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\n\t(g)\tThis amendment becomes effective on October 20, 1999.

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 767 series airplanes was published in the Federal Register on November 23, 1998 (63 FR 64657). That action proposed to require repetitive inspections of certain H-11 tension bolts at each side-of-body kick-load fitting and on the lower splice plate (both located on the wing rear spar) to detect damaged, broken, or improperly sealed bolts; and follow-on actions, if necessary. That action also proposed to require eventual replacement of the existing bolts with new, improved bolts, which constitutes terminating action for the repetitive inspections. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the four comments received. \n\n\tTwo commenters support the proposed rule, and one commenterdoes not object to the proposed rule. \n\nEditorial Changes to the Final Rule \n\n\tThe FAA has determined that it is necessary to clarify the detailed visual inspection of paragraph (a)(1) of the requirements of this AD. The FAA has added the words "of the bolts," to further clarify the inspection area. The final rule has been changed accordingly. \n\nRequest to Delete Certain Descriptive Language \n\n\tOne commenter, the manufacturer, requests that the FAA delete the words "improperly sealed" from paragraphs (a) and (b) of the proposed AD. The commenter states that because the most significant influence of the H-11 bolt fracture is the presence of high pre-load, which cannot be determined by inspection, any anomalies in the bolt sealant will have no effect on the bolt fracture, unless the bolt is highly pre-loaded. The commenter also suggests that using the condition of the H-11 bolt sealant as a guide for bolt replacement will cause unnecessary, unscheduled airplane down time and confusion, as it is likely that improperly sealed bolts will be found. The commenter further adds that a clear definition of an "improperly sealed bolt" is not provided in either the Boeing Service Bulletin or the Notice of Proposed Rulemaking (NPRM). \n\n\tThe FAA concurs with the request to delete certain descriptive language of the AD, as requested by the commenter. The FAA has revised this language throughout the final rule. \n\nRequest to Revise the Compliance Time for the Terminating Action \n\n\tOne commenter requests that the FAA revise the proposed compliance time for the terminating action from 6,000 flight cycles to 9,000 flight cycles. The commenter states that the issue of H-11 bolts fracture is more dependent on calendar time rather than flight cycles. This additional allowance of time would provide high cycle usage operators an equivalent of 48 months calendar time that is provided for low cycle usage operators. \n\n\tThe FAA concurs with this request, and has revisedparagraph (c) of the final rule accordingly. \n\nExplanation of Change Made to Proposal \n\n\tThe FAA has added a note to the final rule to clarify the definition of a detailed visual inspection. \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 with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 177 Model 767 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 70 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 2 work hours per airplane to accomplish the required inspection of the kick-load fitting, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection of the kick-load fitting required by this AD on U.S. operators is estimated to be $8,400, or $120 per airplane, per inspection cycle. \n\n\tIt will take approximately 23 work hours per airplane to accomplish the required inspection of the splice plate, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the inspection of the splice plate required by this AD on U.S. operators is estimated to be $96,600, or $1,380 per airplane, per inspection cycle. \n\n\tIt will take approximately 140 work hours per airplane to accomplish the required replacement, at an average labor rate of $60 per work hour. Parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the cost impact of the replacement required by this AD on U.S. operators is estimated to be $588,000, or $8,400 per airplane. \n\n\tThe cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of thisAD action, and that no operator would accomplish those actions in the future if this AD were not adopted. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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. Afinal 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." \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\n PART 39 - AIRWORTHINESS DIRECTIVES \n\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: