AD 2004-05-19

This amendment adopts a new airworthiness directive (AD) that is applicable to all Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. This action requires an inspection of the rear spar attach pins and front spar attach bolts that attach the horizontal stabilizers to the horizontal stabilizer center section for damage; and follow-on or corrective actions, as applicable. This action is necessary to detect and correct damaged rear spar attach pins or front spar attach bolts, which may lead to failure of the bolts or pins, and consequent loss of the stabilizer and loss of controllability of the airplane. This action is intended to address the identified unsafe condition.

Final rule; request for comments.

2004-05-19 Boeing: Amendment 39-13514. Docket 2004-NM-03-AD. \n\n\tApplicability: All Model 737-600, -700, -700C, -800, and -900 series airplanes, certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously. \n\n\tTo detect and correct damaged rear spar attach pins or front spar attach bolts, which may lead to failure of the bolts or pins, and consequent loss of the stabilizer and loss of controllability of the airplane, accomplish the following: \n\nInitial Inspection \n\n\t(a) Do a detailed inspection of the rear spar attach pins and front spar attach bolts that attach the horizontal stabilizers to the horizontal stabilizer center section for damage (e.g., pitting, corrosion, no plating (pins only), galling (bolts only), or wear), per the Accomplishment Instructions of Boeing Service Bulletin 737-55-1086, dated December 11, 2003. The inspection must be done at the later of the times specified in the threshold and applicable grace period columnsin Table 1 of this AD. \n\nTable 1.-Initial Compliance Time\n\n\nThreshold\nGrace period\n\n\nPrior to the accumulation of 15,000 total flight cycles or 60 months since the date of issuance of the original Airworthiness Certificate or the date of issuance of the Export Certificate of Airworthiness, whichever occurs first.\nFor airplanes on which Boeing Service Bulletin 737-55-1074, dated August 15, 2002, has not been done as of the effective date of this AD: Within 90 days after the effective date of this AD.\n\nFor airplanes on which Boeing Service Bulletin 737-55-1074, dated August 15, 2002, has been done as of the effective date of this AD: Within 24 months or 6,000 flight cycles since accomplishment of the service bulletin, whichever occurs first.\n\n\tNote 1: 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\nNot Damaged and Not A Replaced or Repaired Pin or Bolt: Repetitive Inspections \n\n\t(b) If no damaged rear spar attach pin or front spar attach bolt is found during any detailed inspection required by paragraph (a) of this AD, and if that pin or bolt has not been replaced per paragraph (c) of this AD or repaired per Boeing Service Bulletin 737-55-1086, dated December 11, 2003, repeat the detailed inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 9,000 flight cycles or 36 months, whichever occurs first, for that pin or bolt only. \n\nDamaged Pin or Bolt: Corrective Actions \n\n\t(c) If any damaged rear spar attach pin or front spar attach bolt is found during any inspection required by this AD, beforefurther flight, accomplish applicable corrective actions (e.g., repair; replacement of pin and/or bolt with a new one; and detailed inspection of a stripped pin for pitting, corrosion, or galling) per the Accomplishment Instructions of Boeing Service Bulletin 737-55-1086, dated December 11, 2003. \n\nReplaced or Repaired Pin or Bolt: Repetitive Inspections \n\n\t(d) If any rear spar attach pin or front spar attach bolt has been replaced with a new part per paragraph (c) of this AD, repeat the detailed inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 15,000 flight cycles or 60 months, whichever occurs first, for the replaced pin or bolt only. \n\n\t(e) If any rear spar attach pin or front spar attach bolt has been repaired per paragraph (c) of this AD, repeat the detailed inspection required by paragraph (a) of this AD thereafter at intervals not to exceed 9,000 flight cycles or 36 months, whichever occurs first, for the replaced pin or bolt only.Alternative Methods of Compliance \n\n\t(f)(1) In accordance with 14 CFR 39.19, the Manager, Seattle ACO, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. \n\n\t(2) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. \n\nIncorporation by Reference \n\n\t(g) The actions shall be done in accordance with Boeing Service Bulletin 737-55-1086, dated December 11, 2003. 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 Airplanes, 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 March 24, 2004.

The FAA has received numerous reports indicating that, during incorporation of Boeing Service Bulletin 737-55-1074, damaged rear spar attach pins and front spar attach bolts that attach the horizontal stabilizers to the horizontal stabilizer center section were found on Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes. The damaged bolts and pins have premature wear, corrosion, pitting, and galling. Such damaged rear spar attach pins or front spar attach bolts, if not corrected, may lead to failure of the bolts or pins, which could result in loss of the stabilizer and consequent loss of controllability of the airplane. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Service Bulletin 737-55-1086, dated December 11, 2003. The service bulletin describes procedures for an initial detailed inspection of the rear spar attach pins and front spar attach bolts that attach the horizontal stabilizers to thehorizontal stabilizer center section for damage (e.g., pitting, corrosion, no plating (pins only), galling (bolts only), or wear); and follow-on or corrective actions, as applicable. The follow-on actions include repetitive detailed inspections. The corrective actions include repair of any damaged part; replacement of any damaged pin and/or bolt with a new one; and a detailed inspection of a stripped pin for pitting, corrosion, or galling. \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 registered in the United States, this AD requires accomplishment of the actions specified in the service bulletin described previously. \n\nInterim Action \n\n\tThis is considered to be interim action until final action is identified, at which time the FAA may consider further rulemaking. \n\nDetermination of Rule's Effective Date \n\n\tSince a situation exists that requires theimmediate 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 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\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\nInclude 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 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 2004-NM-03-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. \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: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n\t2. Section 39.13 is amended by adding the following new airworthiness directive: