AD 99-18-01

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-700 and -800 series airplanes, that currently requires revising the Airplane Flight Manual (AFM) to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fitting of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. That AD also provides for optional terminating action for certain repetitive inspections, and requires installing an additional fastener on the elevator tab mast fitting, which terminates the AFM revision and extends certain repetitive inspection intervals. This amendment continues to require certain actions, and revises and adds certain other requirements. This amendment is prompted by a report of a severe vibration incident on a Boeing Model 737-800 series airplane; inspection revealed fracturing of the elevator tab mast fitting and excessive freeplay in the elevator tab. The actions specified in this AD are intended to prevent loss of controllability of the airplane due to excessive freeplay in the elevator tab or a free tab.

Final rule; request for comments

99-18-01 BOEING: Amendment 39-11267. Docket 99-NM-179-AD. Supersedes AD 99-13-51, Amendment 39-11213. \n\n\tApplicability: Model 737-700 and -800 series airplanes having line numbers 1 through 190, 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 (j) 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 loss of controllability of the airplane due to excessive freeplay in the elevator tab or a free tab, accomplish the following: \n\nAirplane Flight Manual (AFM) Revision Required by AD 99-13-51 \n\n\t(a)\tWithin 24 clock hours after July 6, 1999 (the effective date of AD 99-13-51, amendment 39-11213), revise the Limitations Section of the FAA-approved AFM to include the following information. This may be accomplished by inserting a copy of this AD into the AFM. \n\n"Do not operate the airplane at speeds in excess of 310 knots indicated airspeed (IAS) with speed brakes extended. Do not operate the airplane above FL 390." \n\nAction in Event of Speed Brake Deployment \n\n\t(b)\tIn the event of deployment of the speed brakes at speeds in excess of 310 knots IAS, prior to further flight after landing, accomplish the requirements of paragraph (c) of this AD. \n\nInspection and Check Required by AD 99-13-51 \n\n\t(c)\tWithin 10 days after July 6, 1999, perform a high frequency eddy current (HFEC) inspection of the elevator tab mast fitting of the left and right elevator tab assembly to detect cracking, and a one-time elevator tab freeplay check to detect freeplay of the elevator tab, in accordance with Boeing Alert Service Bulletin 737-55A1068, dated June 9, 1999, or Revision 1, dated June 11, 1999. \n\n\t\t(1)\tIf no cracking is found in the elevator tab mast fitting, repeat the HFEC inspection thereafter at intervals not to exceed 15 days, until accomplishment of the actions required by paragraph (g) of this AD. After the effective date of this AD, only the HFEC and detailed visual inspection required by paragraph (f) of this AD shall be accomplished. \n\n\t\t(2)\tIf any cracking is found in the elevator tab mast fitting, prior to further flight, accomplish the requirements of paragraph (h) of this AD. \n\n\t\t(3)\tIf any freeplay is found that is outside the limits specified in the alert service bulletin, prior to furtherflight, perform corrective actions in accordance with the alert service bulletin. \n\n\tNOTE 2: Boeing Alert Service Bulletin 737-55A1068, dated June 9, 1999, references Boeing Model 737-600/-700/-800 Maintenance Manual (AMM), Subjects 27-09-91, 27-31-00, and 51-21-99; 737 Nondestructive Test (NDT) Manual D6-37239, Part 6, Subject 55-00-00; 737 Structural Repair Manual (SRM) Subject 51-20-81; and Operations Manual Service Bulletin D6-27370-TBC ("Elevator Tab Operational Limitations"), dated June 10, 1999; as additional sources of service information to accomplish certain requirements of this AD. \n\nNew AFM Revision \n\n\t(d)\tWithin 24 clock hours after the effective date of this AD, revise the Limitations Section of the FAA-approved AFM to include the following information. This may be accomplished by inserting a copy of this AD into the AFM. Following accomplishment of this AFM revision, remove the AFM revision required by paragraph (a) of this AD from the Limitations Section of theFAA-approved AFM. \n\n"Except as otherwise provided for in the AFM emergency procedures, do not operate the airplane at speeds in excess of 310 knots indicated airspeed (IAS) with speed brakes extended. Do not operate the airplane above FL 390." \n\nAction in Event of Speed Brake Deployment \n\n\t(e)\tIn the event of deployment of the speed brakes at speeds in excess of 310 knots IAS, prior to further flight after landing, accomplish the requirements of \nparagraph (f) of this AD.\n\n Inspections and Check \n\n\tNOTE 3: Accomplishment of the initial HFEC inspection and check required by paragraph (c) of this AD, prior to the effective date of this AD, in accordance with Boeing Alert Service Bulletin 737-55A1068, dated June 9, 1999, is considered acceptable for compliance with the HFEC inspection, detailed visual inspection, and one-time freeplay check required by paragraph (f) of this AD. \n\n\t(f)\tWithin 10 days after the effective date of this AD, perform an HFEC inspection and a detailed visual inspection of the elevator tab mast fittings of the left and right elevator tab assemblies to detect cracking, and a one-time elevator tab freeplay check to detect freeplay of the elevator tabs, in accordance with Boeing Alert Service Bulletin 737-55A1068, Revision 1, dated June 11, 1999. Accomplishment of these actions terminates the inspections and checks required by paragraph (c) of this AD. \n\n\t\t(1)\tIf no cracking is found in any elevator tab mast fitting, repeat the HFEC and detailed visual inspections thereafter at intervals not to exceed 15 days, until accomplishment of the actions required by paragraph (g) of this AD. \n\n\t\t(2)\tIf any cracking is found in any elevator tab mast fitting, prior to further flight, accomplish the replacement action required by paragraph (h) of this AD. \n\n\t\t(3)\tIf any freeplay is found in any elevator tab, which is outside the limits specified in the alert service bulletin, prior to further flight, perform corrective actions in accordance with the alert service bulletin. \n\n\tNOTE 4: 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\tNOTE 5: Boeing Alert Service Bulletin 737-55A1068, Revision 1, dated June 11, 1999, references Boeing Model 737-600/-700/-800 Maintenance Manual (AMM), Subjects 27-09-91, 27-31-00, 27-31-34, and 51-21-99; 737 Nondestructive Test (NDT) Manual D6-37239, Part 6, Subject 51-00-00; 737 Structural Repair Manual (SRM) Subjects 51-20-01, 51-20-07, and 51-21-99; and 737-600/-700/-800 Operations Manual Service Bulletin "Elevator Tab Operational Limitations"; asadditional sources of service information to accomplish certain requirements of this AD. \n\nTime-Limited Modification \n\n\t(g)\tWithin 90 days after July 6, 1999, install an additional high-strength fastener on the elevator tab mast fitting in accordance with Boeing Alert Service Bulletin 737-55A1068, dated June 9, 1999, or Boeing Alert Service Bulletin 737-55A1068, Revision 1, dated June 11, 1999. Accomplishment of this modification constitutes terminating action for the requirements of paragraphs (b), (c), and (e) of this AD. Following accomplishment of the installation, the AFM revision required by paragraphs (a) and (d) of this AD may be removed from the AFM. Following accomplishment of the installation, repeat the HFEC and detailed visual inspection required by paragraph (f) of this AD thereafter at intervals not to exceed 90 days, until accomplishment of paragraph (h) of this AD. \n\nOptional Terminating Action \n\n\t(h)\tReplacement of the elevator tab mast fittings with new, improved tab mast fittings, in accordance with Boeing Service Bulletin 737-55-1063, dated July 1, 1999, constitutes terminating action for the requirements of this AD.\n\n Spares \n\n\t(i)\tAs of the effective date of this AD, no person shall install an elevator tab mast fitting, part number (P/N) 183A8400-1 or 183A8400-2, on any airplane. \n\nAlternative Methods of Compliance \n\n\t(j)\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 6: 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(k)\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(l)\tExcept as provided by paragraphs (a), (b), (e), and (f) of this AD, the actions shall be done in accordance with the following service information, as applicable: \n\n\t\t(1)\tThe incorporation by reference of Boeing Alert Service Bulletin 737-55A1068, Revision 1, dated June 11, 1999, and Boeing Service Bulletin 737-55-1063, dated July 1, 1999, as applicable, was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. \n\n\t\t(2)\tThe incorporation by reference of Boeing Alert Service Bulletin 737-55A1068, dated June 9, 1999, was approved previously by the Director of the Federal Register as of July 6, 1999 (64 FR 34976, June 30, 1999). \n\n\t\t(3)\tCopies 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(m)\tThis amendment becomes effective on September 9, 1999.

On June 22, 1999, the FAA issued AD 99-13-51, amendment 39-11213 (64 FR 34976, June 30, 1999), applicable to certain Boeing Model 737-700 and -800 series airplanes, to require revising the Airplane Flight Manual (AFM) to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fitting of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. That AD also provides for optional terminating action for certain repetitive inspections. In addition, that AD requires installing an additional fastener on the elevator tab mast fitting, which terminates the AFM revision and extends certain repetitive inspections. That action was prompted by a report of a severe vibration incident on a Boeing Model 737-800 series airplane; inspection revealed fracturing of the elevator tab mast fitting and excessive freeplay in the elevator tab. The actions required by that ADare intended to prevent reduced controllability of the airplane due to excessive freeplay in the elevator tab or a free tab. Actions Since Issuance of Previous Rule Since the issuance of that AD, the FAA has reviewed and approved the following new service information: \n\n\tBoeing Alert Service Bulletin 737-55A1068, Revision 1, dated June 11, 1999, describes procedures similar to those described in the original issue of that alert service bulletin, as cited in AD 99-13-51. However, Revision 1 adds a close visual inspection (detailed visual inspection) of the elevator tab mast fitting and revises certain part numbers and references due to typographical errors in the original issue of the alert service bulletin. \n\tBoeing Service Bulletin 737-55-1063, dated July 1, 1999, describes procedures for replacing a cracked elevator tab mast fitting with a new, improved fitting. Such replacement eliminates the need for repetitive inspections of the elevator tab mast fittings. \n\nExplanation ofRequirements of 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 AD supersedes AD 99-13-51 to continue to require revising the AFM to prohibit operation of the airplane under certain conditions; repetitive inspections of the tab mast fitting of the elevator tab assemblies to detect cracking; an elevator tab freeplay check; and corrective actions, if necessary. This AD also continues to provide for optional terminating action only for certain repetitive inspections; and installing an additional fastener on the elevator tab mast fitting, which terminates the AFM revision and extends certain repetitive inspection intervals. This amendment also provides optional terminating action for the requirements of this AD. \n\n\tIt should be noted that, except as otherwise provided for in the AFM emergency procedures, this AD prohibits the deployment of the spoilers at speeds in excess of 310 knots indicated airspeed (IAS) with speed brakes extended. This AD also prohibits the operation of the airplane above FL 390. The FAA recognizes that under emergency circumstances, as specified in the AFM, it might become necessary to deploy spoilers in excess of 310 knots IAS. In that event, this AD requires accomplishment of the high frequency eddy current (HFEC) and detailed visual inspections of the elevator tab mast fittings and of the check of the tabs for freeplay, prior to further flight after landing. \n\nInterim Action \n\n\tThis is considered to be interim action. The FAA is currently considering requiring the currently optional terminating action (replacement of the elevator tab mast fitting with a new, improved fitting). However, the planned compliance time for the replacement is sufficiently long so that notice and opportunity for prior public comment will be practicable. \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 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 99-NM-179-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, 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\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 thecaption "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\n\t2. Section 39.13 is amended by removing amendment 39-11213 (64 FR 34976, June 30, 1999), and by adding a new airworthiness directive (AD), amendment 39-11267, to read as follows: