AD 2002-08-06

This amendment adopts a new airworthiness directive (AD) that is applicable to certain Boeing Model 777-200 and -300 series airplanes. This action requires a one-time torque check (inspection) of the bolts that attach the pivot fittings to the horizontal stabilizer through the upper and lower titanium straps, to determine if the bolts are adequately torqued, and follow-on actions. This action is necessary to prevent failure of the pivot fittings, which could result in loss of control of the horizontal stabilizer and consequent loss of control of the airplane. This action is intended to address the identified unsafe condition.

Final rule; request for comments.

2002-08-06 Boeing: Amendment 39-12714. Docket 2002-NM-38-AD. \n\n\tApplicability: Model 777-200 and -300 series airplanes as listed in Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002; 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\tTo prevent failure of the pivot fittings of the horizontal stabilizer, which could result in loss of control of the horizontal stabilizer and consequent loss of control of the airplane, accomplish the following: \n\nTorque Check (Inspection) \n\n\t(a) Within 90 days after the effective date of this AD, do the following inspections of the aft bolts of the pivot fittings attached to the horizontal stabilizer per the Accomplishment Instructions of Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002: \n\n\t\t(1) Do a torque check (inspection) to determine if the bolts are adequately torqued per the service bulletin. \n\n\t\t(2) Do a detailed inspection of the bolt thread protrusion through the nut. Replace any bolt that has less than the chamfer of the bolt or more than three threads protruding through the nut per Steps 6.d. and 6.e. or Steps 7.d. and 7.e. of the Work Instructions of the service bulletin for Group 1 or Group 2 airplanes, as applicable. \n\n\n\tNote 2: For the purposes of this AD, a detailed 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\tNote 3: For Group 1 airplanes and Group 2 airplanes with WBnnn variable numbers (where nnn is any three digits); inspections and follow-on actions done before the effective date of this AD per Boeing Service Bulletin 777-55A0013, dated December 19, 2001, are considered acceptable for compliance with the corresponding actions specified in paragraph (a)(1) of this AD. \n\nFollow-On Actions \n\n\t(3) Do Steps 8. and 9. of the Work Instructions in Part B of theservice bulletin if the torque value of all attachment bolts is found to be within the specified limits, then no further action is required by this AD. \n\n\t(b) During the inspection required by paragraph (a)(1) of this AD, if the torque value of any attachment bolt is found to be less than or equal to the value specified in Step 4. of the Work Instructions of Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002: Before further flight, do all actions (includes removing the nut and measuring run-on torque; replacing any nut that does not meet the run-on torque requirements; a visual inspection for indications of galling, fretting, and wear; replacing the bolt if any discrepancies are found; and an open-hole high frequency eddy current (HFEC) inspection for cracks), as specified in and per Steps 5., 6., and 7., as applicable, of the Work Instructions of Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002, for Group 1 or Group 2 airplanes, as applicable. \n\n\t(c) If any cracking is found during the HFEC inspection and the service bulletin specifies contacting Boeing for repair instructions: Before further flight, 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, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. \n\nReporting Requirement \n\n\t(d) After doing the inspections required by paragraph (a) of this AD: Submit a report of the bolt torque values and run-on torque values of the nut, and/or any damaged areas found, to the FAA Certification Management Office--Boeing, ANM-108B, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; at the applicable time specified in paragraph (d)(1) or (d)(2) of this AD. Information collection requirements contained in this AD have been approved by the Office of Management and Budget (OMB) under the provisions of the Paperwork Reduction Act of 1980 (44 U.S.C. 3501 et seq.) and have been assigned OMB Control Number 2120-0056. \n\n\t\t(1) For airplanes on which the inspection is done after the effective date of this AD: Submit the report within 10 days after doing the inspection.\n \n\t\t(2) For airplanes on which the inspection was done before the effective date of this AD: Submit the report within 30 days after the effective date of this AD.\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 4: 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) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002. 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 May 3, 2002.

The FAA has received a report of improperly torqued bolts that attach the pivot fittings to the horizontal stabilizer on certain Boeing Model 777-200 and -300 series airplanes. The improper torqueing occurred during production. Two pivot fittings attach the aft part of the horizontal stabilizer to the body structure. Two titanium straps attach the upper and lower surface of each pivot fitting to the upper and lower surface of the horizontal stabilizer. The straps are attached to the pivot fitting with eight bolts at each location. Insufficient bolt torque in multiple locations will cause the bolts to loosen and may cause failure of the pivot fittings. Such failure could result in loss of control of the horizontal stabilizer and consequent loss of control of the airplane. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 777-55A0013, Revision 1, dated January 31, 2002, which describes procedures for a torque check (inspection) of the two aft rows of bolts which attach the pivot fittings to the horizontal stabilizer through the upper and lower titanium straps, to determine if the bolts are adequately torqued, and follow-on actions. \n\n\tFor Group 1 airplanes, the follow-on actions include removing the nut and measuring run-on torque if the torque value is between 300 inch-pounds and 1,550 inch-pounds measured on the nut side (1,705 inch-pounds measured on the head side). Replace any nut that does not meet the run-on torque requirements; if the torque values on one to three bolts in a joint are less than 300 inch-pounds, remove the bolts with those values. Do a visual inspection for indications of galling, fretting, and wear, and replace the bolt if discrepancies are found, then do an open-hole high frequency eddy current (HFEC) inspection for cracks; oversize the holes if cracks are found or the hole is not round; and install new oversize bolts. If the torque values of four or more bolts in a joint are less than 300 inch-pounds, remove all the bolts in the joint (maximum of four bolts at one time); and repeat the visual and HFEC inspections specified above. \n\n\tFor Group 2 airplanes, the follow-on actions include removing the nut and measuring run-on torque if the torque value on any bolt is between 400 inch-pounds and 2,100 inch-pounds measured on the nut side (2,310 inch-pounds measured on the head side). Replace any nut that does not meet the run-on torque requirements; if the torque values on one to three bolts in a joint are less than 400 inch-pounds, remove the bolts with those values. Do a visual inspection for indications of galling, fretting, and wear, and replace the bolt if any discrepancies are found, then do an open-hole HFEC inspection for cracks; oversize the holes if cracks are found or the hole is not round; and install new oversize bolts. If the torque values of four or more bolts in a joint are less than 400 inch-pounds, remove all thebolts in the joint (maximum of four bolts at one time); and repeat the visual and HFEC inspections specified above. \n\n\tAccomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. \n\nExplanation of the Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design, this AD requires accomplishment of the actions specified in the service bulletin described previously, except as discussed below. \n\nDifferences Between This AD and Alert Service Bulletin \n\n\tThis AD differs from the referenced service bulletin in the following ways: \n\nThe service bulletin recommends doing the torque check (inspection) "within 90 days after the revision date of service bulletin," but this AD requires the inspection be done within 90 days after the effective date of the AD. \n\nThe service bulletin specifies that the manufacturer may be contacted for disposition of certain repair conditions. This AD requires the repair of those conditions to be accomplished per a method approved by the 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 Aircraft Certification Office, to make such findings. \n\nIn Steps 4. and 5. of the Work Instructions of the service bulletin, the procedure to verify that there is no less than the chamfer of the bolt and no more than three threads protruding through the nut (as specified in Steps 6.e. and 7.e. of the Work Instructions) was inadvertently omitted. Replacement of the bolts if more than three threads are protruding also was omitted from those steps in the service bulletin. This AD requires that check and replacement, if necessary, be done per Step 6.e. or 7.e. of the Work Instructions of the service bulletin. \n\nThe service bulletin identifies the inspection described only as a "visual inspection." For clarity, this AD refers to that inspection as a "detailed inspection." Note 2 of this AD defines such an inspection. \n\nDetermination of Rule's Effective Date \n\n\tSince a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications receivedon or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\t\tSubmit comments using the following format: \n\nOrganize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues. \n\nFor each issue, state what specific change to the AD is being requested. \n\n Include justification (e.g., reasons or data) for each request. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket forexamination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2002-NM-38-AD." The postcard will be date stamped and returned to the commenter. \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\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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 forpart 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: