AD 99-14-05

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 777-200 series airplanes, that requires inspections to verify correct installation of certain fasteners located on the trailing edges of the horizontal and vertical stabilizer; replacement of the existing fasteners with new fasteners installed with wet sealant; and follow-on actions, if necessary. This amendment is prompted by reports indicating that, during manufacture of the horizontal and vertical stabilizers, certain fasteners attaching the aluminum ribs and brackets to the trailing edges on the empennage were not correctly installed with wet sealant. The actions specified by this AD are intended to prevent corrosion and possible cracking of those aluminum parts, which could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane.

Final rule

99-14-05 BOEING: Amendment 39-11214. Docket 98-NM-243-AD. \n\n\tApplicability: Model 777-200 series airplanes, line numbers 15 through 33, excluding line number 18; 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 (b) 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 prevent corrosion and possible cracking of the aluminum ribs and brackets of the trailing edges on the empennage, which could result in loss of the attachment of the elevator and rudder to the empennage and consequent reduced controllability of the airplane, accomplish the following: \n\n\t(a)\tWithin five years since the date of manufacture of the airplane, perform visual inspections of the specified number of fasteners installed in each zone on the aluminum ribs and brackets located on the trailing edges of the horizontal and vertical stabilizer to verify correct installation of fasteners with wet sealant, in accordance with Boeing Alert Service Bulletin 777-55A0005, Revision 1, dated June 4, 1998. Following the inspection, oversize the holes for all removed fasteners, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin \n\n\t\t(1)\tIf the fasteners are correctly installed with wet sealant, no further actionis required for that zone. \n\n\t\t(2)\tIf the fasteners are not correctly installed with wet sealant in any zone, remove the remaining fasteners in that zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin. \n\n\t\t(3)\tIf it cannot be determined that the fasteners are correctly installed with wet sealant, remove and inspect the specified number of additional fasteners in that zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin. \n\n\t\t\t(i)\tIf, after removal, all additional fasteners inspected in that zone are found to be correctly installed with wet sealant, no further action is required for that zone. \n\n\t\t\t(ii)\tIf, after removal, the fasteners in that zone are found to be incorrectly installed, remove all other fasteners in the zone, oversize the holes, apply primer, and install new, oversize fasteners with wet sealant, in accordance with the alert service bulletin.\n\n Alternative Methods of Compliance \n\n\t(b)\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 2: 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(c)\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(d)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 777-55A0005, Revision 1, dated June 4, 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(e)\tThis amendment becomes effective on August 4, 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 777-200 series airplanes was published in the Federal Register on October 14, 1998 (63 FR 55065). That action proposed to require inspections to verify correct installation of certain fasteners located on the trailing edges of the horizontal and vertical stabilizer; replacement of the existing fasteners with new fasteners installed with wet sealant; and follow-on actions, if necessary. \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 comments received. \n\n\tOne commenter supports the proposed rule; another commenter indicates that it is not affected by the proposed rule. \n\nRequest to Extend Compliance Time \n\n\tOne commenter (an operator) requests that the FAA extend the proposedcompliance time for accomplishment of the actions from five years to six years since the date of manufacture of the airplane. The commenter indicates that its airplanes were delivered in February and March of 1996, which would require the inspections to be accomplished within 2.2 years. In support of the request for extension, if approved by the FAA, the commenter states that it will immediately apply corrosion inhibiting compound to the area, inspect the fastener holes for corrosion after oversizing, and remove any detected corrosion. \n\n\tThe FAA does not concur with the commenter's request and proposal. If the fasteners were not correctly installed with wet sealant in production, the application of corrosion inhibiting compound prior to further flight would have limited effectiveness for corrosion prevention. In light of the fact that there is continued degradation of the structure due to corrosion, the FAA has determined that a one year extension is not warranted. No change tothe final rule is necessary in this regard. \n\nRequest to Revise Cost Impact Information \n\n\tOne commenter requests that the cost impact information for accomplishment of the inspections of the horizontal and vertical stabilizer as stated in the proposed rule be revised to reflect the work hours and associated costs specified in the service bulletin. The commenter also states that the work hours and cost for replacement of any incorrectly installed fasteners, in addition to the cost for the fastener repair kit, should be included in the economic analysis. \n\n\tThe FAA does not concur that a change to the cost impact information is necessary. The inspections of the horizontal and vertical stabilizer that the commenter refers to are inspections that must be accomplished to detect incorrect installation of any fasteners. The cost impact information, restated below, describes only the "direct" costs of the specific actions required by this AD. The number of work hours represents thetime necessary to perform only the inspections actually required by this AD. The FAA recognizes that, in accomplishing the requirements of any AD, operators may incur "incidental" costs in addition to the "direct" costs. The cost analysis in AD rulemaking actions, however, typically does 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\n\tIn addition, the economic analysis of the AD is limited to the cost of actions actually required by the rule. It does not consider the costs of "on condition" actions such as replacement of an incorrectly installed fastener if one is detected during a required inspection ("replace, if necessary"). Such "on-condition" replacement would be required to be accomplished regardless of AD direction, in order to correct an unsafe condition identified in an airplane and to ensure operation of that airplane in an airworthy condition, as required by the Federal Aviation Regulations. \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 18 airplanes of the affected design in the worldwide fleet. The FAA estimates that 2 airplanes of U.S. registry will be affected by this AD. \n\n\tIt will take approximately 331 work hours per airplane to accomplish the required inspection of the horizontal stabilizer, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection, as required by this AD, on U.S. operators is estimated to be $39,720, or $19,860 per airplane. \n\n\tIt will take approximately 206 work hours per airplane to accomplish the required inspection of the vertical stabilizer, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of this inspection, as required by this AD, on U.S. operators is estimated to be $24,720, or $12,360 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 this AD 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. 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\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 addingthe following new airworthiness directive: