AD 2001-23-01

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-600, -700, and -800 series airplanes, that currently requires repetitive inspections of certain elevator hinge plates, and corrective action, if necessary. That AD also provides for an optional replacement of the elevator hinge plates with new, improved hinge plates, which would end the repetitive inspections. This amendment requires accomplishment of the previously optional replacement of the elevator hinge plates with new, improved hinge plates, as terminating action for the repetitive inspections. The actions specified by this AD are intended to prevent fatigue cracking of the elevator hinge plates, which could lead to the loss of the attachment of the elevator to the horizontal stabilizer, and consequent reduced controllability of the airplane. This action is intended to address the identified unsafe condition. \n\n\tThe incorporation by reference of certain publications listed in the regulations was approved previously by the Director of the Federal Register as of April 9, 2001 (66 FR 16116, March 23, 2001).

Final rule

2001-23-01 Boeing: Amendment 39-12498. Docket 2001-NM-20-AD. Supersedes AD 2001-06-08, Amendment 39-12155. \n\n\tApplicability: Model 737-600, -700, and -800 series airplanes; line numbers 1 through 84 inclusive; 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 fatigue cracking of the elevator hinge plates, which could lead to the loss of the attachment of the elevator to the horizontal stabilizer, and consequent reduced controllability of the airplane, accomplish the following: \n\nRestatement of Requirements of AD 2001-06-08 \n\nInspections and Corrective Actions \n\n\t(a) Prior to the accumulation of 7,000 total flight cycles or within 90 days after April 9, 2001 (the effective date of AD 2001-06-08), whichever occurs later, perform high frequency eddy current and detailed visual inspections of the hinge plate at elevator hinge 4, and a detailed visual inspection of the elevator hinge plate lugs (three locations) at elevator hinges 3, 5, 6, 7, and 8. Do these inspections per Part I of the Accomplishment Instructions of Boeing Service Bulletin 737-55-1067, dated October 19, 2000. Repeat the inspections thereafter no later than every 4,000 flight cycles, per the service bulletin, until paragraph (b) of this AD has been accomplished. If any cracking or unusual wear (i.e., elongated holes, loose or missing nuts or bolts, or missing primer or finish) is found during any inspection per this paragraph, before further flight, replace the affected hinge plate with a new, improved hinge plate, and modify the elevator upper skin, the upper and lower hinge covers, and the upper and lower closure panels, as applicable, per the service bulletin, except as provided by paragraph (c) of this AD. Such replacement and modification ends the repetitive inspections for the replaced hinge plate. \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\nNew Requirements of This AD \n\nReplacement of Hinge Plates \n\n\t(b) Before the accumulation of 15,000 total flight cycles, or within 5 years since the airplane's date of manufacture, whichever occurs first: Replace the elevator hinge plates at hinges 3, 4, 5, 6, 7, and 8, with new, improved hinge plates; per Part II of the Accomplishment Instructions of Boeing Service Bulletin 737-55-1067, dated October 19, 2000, except as provided by paragraph (c) of this AD. The replacement includes modification of the elevator upper skin, the upper and lower hinge covers, and the upper and lower closure panels, as applicable. Doing this replacement ends the repetitive inspections required by this AD. \n\nException to Service Bulletin Instructions: Wear Limits \n\n\t(c) During the replacement of elevator hinge plates per paragraph (a) or (b) of this AD, where Boeing Service Bulletin 737-55-1067, dated October 19, 2000, specifies to contact Boeing for wear limits, before further flight, contact the Manager, Seattle Aircraft Certification Office (ACO), FAA, or a Boeing Company Designated Engineering Representative who has been authorized by the Manager, Seattle ACO, to make such findings. For wear limits to be approved by the Manager, Seattle ACO, as required by this paragraph, the Manager's approval letter must specifically reference this AD. \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 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO.Special Flight Permits \n\n\t(e) 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(f) Except as provided by paragraph (c) of this AD, the actions shall be done in accordance with Boeing Service Bulletin 737-55-1067, dated October 19, 2000. This incorporation by reference was approved previously by the Director of the Federal Register as of April 9, 2001 (66 FR 16116, March 23, 2001). 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(g) This amendment becomes effective on December 19, 2001.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 2001-06-08, amendment 39-12155 (66 FR 16116, March 23, 2001); which is applicable to certain Boeing Model 737-600, -700, and -800 series airplanes; was published in the Federal Register on June 29, 2001 (66 FR 34591). The action proposed to continue to require repetitive inspections of certain elevator hinge plates, and corrective action, if necessary. That AD also provides for an optional replacement of the elevator hinge plates with new, improved hinge plates, which would end the repetitive inspections. This AD requires accomplishment of the previously optional replacement of the elevator hinge plates with new, improved hinge plates, as terminating action for the repetitive inspections. \n\nComment \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the single comment received. \n\nExtend Compliance Time \n\n\tThe commenter asks that the compliance time of "Before the accumulation of 15,000 total flight cycles, or within 5 years since the airplane's date of manufacture, whichever occurs first," as specified in paragraph (b) of the proposed rule, be extended to whichever occurs later. The commenter states that this change will result in an acceptable level of safety, and allow operators to accomplish the work within existing maintenance visits. \n\n\tThe FAA does not agree with the commenter's request to extend the compliance time for the hinge replacement required by paragraph (b) of the final rule. With regard to extending the compliance time to allow the replacement to be accomplished within existing maintenance visits, we have considered factors such as operators' maintenance schedules in setting a compliance time for the required replacement. We have determined the compliance time specified in paragraph (b) of the final rule is an appropriate compliance time in which the replacement may be accomplished during scheduled airplane maintenance for the majority of affected operators. Since maintenance schedules vary from operator to operator, it would not be possible to guarantee that all affected airplanes could be modified during scheduled maintenance. Therefore, we find the compliance time represents the maximum time wherein the affected airplanes may continue to operate without compromising safety. No change to the final rule is necessary. \n\nConclusion \n\n\tThe FAA has determined that air safety and the public interest require the adoption of the rule as proposed. \n\nCost Impact \n\n\tThere are approximately 84 airplanes of the affected design in the worldwide fleet. The FAA estimates that 39 airplanes of U.S. registry will be affected by this AD. \n\n\tThe inspections that are currently required by AD 2001-06-08 take approximately 4 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the currently required actions on U.S. operators is estimated to be $9,360, or $240 per airplane, per inspection cycle. \n\n\tThe new replacement that is required by this AD action will take approximately 44 work hours per airplane to accomplish, at an average labor rate of $60 per work hour. Required parts will cost approximately $13,116 per airplane. Based on these figures, the cost impact of the requirements of this AD on U.S. operators is estimated to be $614,484, or $15,756 per airplane. \n\n\tThe cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. \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\tFor the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and (3) will not have a significant economic impact, positive or negative, on a substantial number of small entities under the criteria of the Regulatory Flexibility Act. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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: \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 removing amendment 39-12155 (66 FR 16116, March 23, 2001), and by adding a new airworthiness directive (AD), amendment 39-12498, to read as follows: