AD 2001-09-51

This document publishes in the Federal Register an amendment adopting airworthiness directive (AD) 2001-09-51 that was sent previously to all known U.S. owners and operators of Boeing Model 737-600, -700, -700C, and -800 series airplanes by individual notices. This AD requires inspection of the small jam nut on the elevator tab control rods to detect inspection putty and to determine its condition; a torque check of the small and large jam nuts on the tab control rod, if necessary; and corrective actions, as applicable. For certain airplanes, this AD also requires a one-time inspection for torque of the small and large jam nuts on the tab control rods; and corrective actions, as applicable. This action is prompted by reports indicating that operators found problems with the elevator tab control rods during accomplishment of an existing AD. The actions specified by this AD are intended to prevent excessive freeplay in the tab control mechanism, which could result in elevator tab flutter and consequent loss of controllability of the airplane.

Final rule; request for comments.

2001-09-51 Boeing: Amendment 39-12251. Docket 2001-NM-126-AD. \n\n\tApplicability: Model 737-600, -700, -700C, and -800 series airplanes, line numbers 1 through 788 inclusive, 790 through 814 inclusive, 816, 819, 821, and 823, 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\tTo prevent excessive freeplay in the tab control mechanism, which could result in elevator tab flutter, and consequent loss of controllability of the airplane, accomplish the following: \n\nInspection and Corrective Actions \n\n\t(a) Within 10 days after the effective date of this AD, inspect the small jam nut on the elevator tab control rods to detect inspection putty and to determine its condition, per paragraph III.B. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1245, dated April 23, 2001. \n\n\t\t(1) If inspection putty is found and it is intact, no further action is required by paragraph (a) of this AD. \n\n\t\t(2) If inspection putty is missing or detached, prior to further flight, perform a torque check of the small and large jam nuts on the tab control rod, in accordance with paragraph III.B. of the alert service bulletin. Prior to further flight, perform corrective actions (includingperforming a detailed visual inspection of the threads on the rod end bearing for wear, measuring the diameter of the threads on the rod end bearing, replacing the rod end bearing and the threaded adjustment bushing, torquing the jam nuts, and applying inspection putty), as applicable, per paragraph III.B. of the alert service bulletin. If the tab control rod is disassembled and if no wear is found during accomplishment of the detailed visual inspection specified in this paragraph, measuring the diameter of the threads on the rod end bearing may be deferred until 250 flight cycles or 30 days after the effective date of this AD, whichever occurs first. \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) For any control rod jam nut on which the putty was found and was intact, as specified in paragraph (a)(1) of this AD: Within 250 flight cycles or 30 days after the effective date of this AD, whichever occurs first, perform a one-time inspection for torque of the small and large jam nuts on the tab control rods, per paragraph III.C. of the Accomplishment Instructions of Boeing Alert Service Bulletin 737-27A1245, dated April 23, 2001. Prior to further flight, perform corrective actions (including performing a detailed visual inspection of the threads on the rod end bearing for wear, measuring the diameter of the threads on the rod end bearing, replacing the rod end bearing and the threaded adjustment bushing, torquing the jam nuts, and applying inspection putty), as applicable, per paragraph III.C. of the alert service bulletin. \n\nReporting Requirement \n\n\t(c) Within 15 days after accomplishing the inspections required by paragraphs (a) and (b) of this AD, submit a report of inspection findings, positive or negative, to Boeing per paragraph I.C. of the Planning Information of Boeing Alert Service Bulletin 737-27A1245, dated April 23, 2001. 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\nAlternative Methods of Compliance \n\n\t(d) 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 Aircraft Certification Office (ACO), FAA. 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\nIncorporation by Reference \n\n\t(e) The actions shall be done in accordance with Boeing Alert Service Bulletin 737-27A1245, dated April 23, 2001. 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(f) This amendment becomes effective on June 18, 2001, to all persons except those persons to whom it was made immediately effective by emergency AD 2001-09-51, issued on April 24, 2001, which contained the requirements of this amendment.

On April 24, 2001, the FAA issued emergency AD 2001-09-51, which is applicable to certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. \n\n\tThat action was prompted by reports indicating that, during accomplishment of actions required by AD 2001-04-08, amendment 39-12127 (66 FR 13229, March 5, 2001), operators found problems with the elevator tab control rods on certain Boeing Model 737-700 and -800 series airplanes. One operator found jam nuts that had been installed improperly. Two other operators reported damage that was attributed to inadequately torqued jam nuts. The control rod jam nuts may not have been torqued properly when the control rod length was rigged at Boeing prior to delivery of the airplanes. \n\n\tImproperly torqued jam nuts on the elevator tab control rods could result in damage to the tab control rod. If both tab control rods are damaged, excessive freeplay in the tab control mechanism can occur, which could result in elevator tab flutter. This condition, if not corrected, could result in loss of controllability of the airplane. \n\n\tThe elevator tab control rods on Model 737-600 and -700C series airplanes are identical to those on the affected Model 737-700 and -800 series airplanes. Therefore, those Model 737-600 and -700C series airplanes may be subject to the same unsafe condition revealed on Model 737-700 and -800 series airplanes. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 737-27A1245, dated April 23, 2001, which describes procedures for inspecting the small jam nut on the elevator tab control rods to detect inspection putty and to determine its condition; a torque check of the small and large jam nuts on the tab control rod, if necessary; and corrective actions (including performing a detailed visual inspection of the threads on the rod end bearing for wear, measuring the diameter of the threads on the rod end bearing, replacing the rod end bearing and the threaded adjustment bushing, torquing the jam nuts, and applying inspection putty), as applicable. \n\n\tFor any control rod jam nut on which the putty is found and is intact, the alert service bulletin also describes procedures for a one-time inspection for torque of the small and large jam nuts on the tab control rods; and corrective actions (including performing a detailed visual inspection of the threads on the rod end bearing for wear, measuring the diameter of the threads on the rod end bearing, replacing the rod end bearing and the threaded adjustment bushing, torquing the jam nuts, and applying inspection putty), as applicable. \n\nExplanation of Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of this same type design, this airworthiness directive is issued to require the actions specified in the alert service bulletin described previously. The actions are requiredto be accomplished in accordance with the alert service bulletin described previously. \n\n\tThis AD also requires that operators report both positive and negative results of inspections to Boeing. \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 notices issued on April 24, 2001, to all known U.S. owners and operators of Boeing Model 737-600, -700, -700C, and -800 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\nClarification of Applicability \n\n\tFor clarification, the FAA notes that, while the alert service bulletin does not specify that Model 737-700C series airplanes are subject to the actions in the alert service bulletin, the list of affected line numbers in the applicability of this AD includes the line numbers of certain Model 737-700C series airplanes. \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 2001-NM-126-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, Incorporationby 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: \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: