AD 97-08-51

This document publishes in the Federal Register an amendment adopting Airworthiness Directive (AD) T97-08-51 that was sent previously to all known U.S. owners and operators of Boeing Model 767 series airplanes by individual telegrams. This AD requires an inspection to ensure that all bolts of the hinge fitting assembly support beam on both the left- and right-hand outboard trailing edge flaps are the correct length and type, and correction of any discrepancy found. This action is prompted by a report indicating that a 20-foot section of the right-hand outboard trailing edge flap separated from the airplane due to failure of four bolts of the most inboard hinge fitting. The actions specified by this AD are intended to detect and correct such failed bolts, which could result in loss of an outboard trailing edge flap, and consequent reduced controllability of the airplane.

Final rule; request for comments

97-08-51 BOEING: Amendment 39-10012. Docket 97-NM-66-AD.\n\n\tApplicability: Model 767 series airplanes, 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 separation of the outboard trailing edge flap from the airplane due to failed bolts of the attach fitting, accomplish the following: \n\n\t(a)\tPerform an inspection to check the bolt torque, bolt length, and type of all bolts of both hinge fittings on the left- and right-hand outboard trailing edge flaps, in accordance with Boeing Alert Service Bulletin 767-27A0151, Revision 1, dated April 2, 1997. Perform these inspections at the time specified in paragraph (a)(1) or (a)(2) of this AD, as applicable.\n\n\t\t(1)\tFor airplanes that have accumulated 15,000 total flight cycles or more, or 37,500 total flight hours or more, as of the effective date of this AD: Perform the inspections within 15 days after the effective date of this AD.\n\n\t\t(2)\tFor all other airplanes: Perform the inspections at the later of the times specified in paragraphs (a)(2)(i) and (a)(2)(ii) of this AD. \n\n\t\t\t(i)\tPrior to the accumulation of 10,000 total flight cycles, or 25,000 total flight hours, whichever occurs first. \n\n\t\t\t(ii)\tWithin 30 days after the effective date of this AD. \n\t(b)\tIf any bolt of the hinge fittings of the left- and right-hand outboard trailing edge flaps is below the torque check threshold specified in Boeing Alert Service Bulletin 767-27A0151, Revision 1, dated April 2, 1997: Prior to further flight, accomplish the action specified in paragraph (b)(1) or (b)(2) of this AD in accordance with the alert service bulletin. \n\n\t\t(1)\tPerform a dye penetrant inspection of all the bolts of the hinge fitting to detect any cracking or discrepancy. \n\n\t\t\t(i)\tIf no cracking or discrepancy is detected, reinstall the bolt using new nuts and washers. \n\t\t\t(ii)\tIf any cracking or discrepancy is detected, replace the cracked or discrepant bolt with a new or serviceable bolt. \n\n\t\t(2)\tReplace all of the bolts of both hinge fittings with new or serviceable bolts. \n\n\t(c)\tIf the length or type of any bolt of the hinge fittings of the left- and right-hand outboard trailing edge flaps is outside the specifications ofBoeing Alert Service Bulletin 767-27A0151, Revision 1, dated April 2, 1997: Prior to further flight, replace the bolt with a new or serviceable bolt in accordance with the alert service bulletin. \n\n\t(d)\tWithin 10 days after accomplishing the actions required by this AD, submit a report describing any cracking, damage, or any torque check of any bolt of either hinge fitting that was below the threshold of the torque check specified by this AD, to the Manager, Seattle Aircraft Certification Office (ACO), 1601 Lind Avenue, SW., Renton, Washington 98055-4056; fax (206) 227-1181. Information collection requirements contained in this regulation 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(e)\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\n\t(f)\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\n\t(g)\tThe actions shall be done in accordance with Boeing Alert Service Bulletin 767-27A0151, Revision 1, dated April 2, 1997. 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(h)\tThis amendment becomes effective on May 7, 1997, to all persons except those persons to whom it was made immediately effective by telegraphic AD T97-08-51, issued on April 2, 1997, which contained the requirements of this amendment.

On April 2, 1997, the FAA issued telegraphic AD T97-08-51, which is applicable to all Boeing Model 767 series airplanes.\n\n\tThat action was prompted by a report indicating that a 20-foot section of the right-hand outboard trailing edge flap separated from a Boeing Model 767 series airplane during approach for landing. During the approach, a "spoiler up flaps 15" configuration was used as part of a high descent rate approach, which is typically associated with high applied loads on the hinge fittings of the outboard trailing edge flap. Additionally, the numbers 9 and 12 spoilers were damaged, which suggests that, upon separation from the airplane, the flap hit the spoilers. Analysis of the flap structure revealed that four bolts of the most inboard hinge fitting had failed. \n\n\tOn-site investigation of the four failed bolts revealed that one bolt had been completely severed due to fatigue that occurred some time prior to the loss of the section of theflap. The investigation also revealed that two of the bolts had been partially severed (roughly 20-30 percent of the bolt diameter), and that one bolt failed from static overload. \n\n\tFailure of the bolts, if not detected and corrected, could result in loss of an outboard trailing edge flap, and consequent reduced controllability of the airplane. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 767-27A0151, Revision 1, dated April 2, 1997, which describes procedures for the following actions: \n\t- Performing a torque check inspection to ensure that all bolts of the hinge fitting assembly support beam on both the left- and right-hand outboard trailing edge flaps are within specified torque range; \n\t- An inspection to verify the bolt length and type of all the bolts of both hinge fittings, and correction of any discrepancy found; \n\t- Replacing all six assembly bolts with new or serviceable bolts, or performing a dye penetrant inspection to detect cracking and/or discrepancies of any bolt that is below the threshold of the torque check; \n\t- Replacing any cracked or damaged bolt with a new or serviceable bolt; and \n\t- Performing an inspection to ensure that shims are installed, and an inspection to ensure that the radius filler is correctly installed. \n\nExplanation of Requirements of the Rule \n\n\tSince the unsafe condition described is likely to exist or develop on other airplanes of the same type design, the FAA issued Telegraphic AD T97-08-51 to prevent separation of the outboard trailing edge flap due to failed bolts of the hinge fitting. The AD requires an inspection to ensure that all bolts of the hinge fitting assembly support beam on both the left- and right-hand outboard trailing edge flaps are within specified torque range. Additionally, this AD requires an inspection to ensure that all bolts of the hinge fitting assembly support beam on both the left- and right-hand outboard trailing edge flaps are the correct length and type, and correction of any discrepancy found. For any bolt that is outside the specified torque range, this AD requires either replacing all six bolts of the hinge fitting assembly with new or serviceable bolts, or performing a dye penetrant inspection to detect cracking or discrepancies of the bolts. For airplanes on which any cracked or discrepant bolt is found, this AD requires replacement of the bolt with a new or serviceable bolt. \n\n\tThe actions are required to be accomplished in accordance with the alert service bulletin previously described. \n\n\tSince it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual telegrams issued on April 2, 1997, to all known U.S. owners and operators of Boeing Model 767 series airplanes. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons. \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 received on 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\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 for examination 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 97-NM-66-AD." The postcard will be date stamped and returned to the commenter. \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, oron 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\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 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: