AD 98-26-24

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Boeing Model 737-100 and -200 series airplanes, that currently requires replacement of certain outboard and inboard wheel halves with improved wheel halves; cleaning and inspecting certain outboard and inboard wheel halves for corrosion, missing paint in large areas, and cracks; and repair or replacement of the wheel halves with serviceable wheel halves, if necessary. That AD was prompted by a review of the design of the flight control systems on Model 737 series airplanes. This amendment requires that the actions be accomplished in accordance with revised service information. The actions specified by this AD are intended to prevent failure of the wheel flanges, which could result in damage to the hydraulics systems, jammed flight controls, loss of electrical power, or other combinations of failures; and consequent reduced controllability of the airplane.

Final rule.

98-26-24 BOEING: Amendment 39-10967. Docket 98-NM-72-AD. Supersedes AD 97-17-01, Amendment 39-10102. \n\n\tApplicability: Model 737-100 and -200 series airplanes equipped with Bendix main wheel assemblies having part number (P/N) 2601571-1, 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 (c)(1) 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 failure of the wheel flanges, which could result in damage to the hydraulics systems, jammed flight controls, loss of electrical power, or other combinations of failures; and consequent reduced controllability of the airplane; accomplish the following: \n\n\tNOTE 2: Allied Signal, Aircraft Landing Systems, Service Information Letter (SIL) #619, dated February 26, 1997, is an additional source of service information for appropriate wheel half serial numbers. \n\n\t(a)\tFor airplanes equipped with a Bendix main wheel assembly having P/N 2601571-1 with an inboard wheel half with serial number (S/N) B-5898 or lower, or S/N H-1721 or lower; or with an outboard wheel half with S/N B-5898 or lower, or S/N H-0863 or lower; accomplish the following: \n\n\t\t(1)\tWithin 180 days after September 16, 1997 (the effective date of AD 97-17-01, amendment 39-10102, 62 FR 43067), and thereafter at eachtire change until the replacement required by paragraph (b) of this AD is accomplished: Accomplish the actions specified in paragraphs (a)(1)(i), (a)(1)(ii), and (a)(1)(iii) of this AD, in accordance with the Accomplishment Instructions of Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988, or Allied Signal Service Bulletin No. 737-32-026, dated June 27, 1988, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988. After the effective date of this AD, only Allied Signal Service Bulletin No. 737-32-026, dated June 27, 1998, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988, shall be used. \n\n\t\t\t(i)\tClean any inboard and outboard wheel half specified in paragraph (a) of this AD. And \n\n\t\t\t(ii)\tInspect the wheel halves for corrosion or missing paint. If any corrosion is found, or if any paint is missing in large areas, prior to further flight, strip or remove paint, and remove any corrosion. And(iii)\tPerform an eddy current inspection to detect cracks of the bead seat area. \n\n\t\t(2)\tIf any cracking is found during the inspections required by this paragraph, prior to further flight, repair or replace the wheel halves with serviceable wheel halves in accordance with procedures specified in the Component Maintenance Manual. \n\n\t(b)\tFor airplanes equipped with a Bendix main wheel assembly having P/N 2601571-1 with an inboard wheel half with S/N B-5898 or lower, or S/N H-1721 or lower; or with an outboard wheel half with S/N B-5898 or lower, or S/N H-0863 or lower; accomplish the following: Within 2 years after September 16, 1997, accomplish the actions specified in paragraphs (b)(1) and (b)(2) of this AD, in accordance with Bendix Service Information Letter 392, Revision 1, dated November 15, 1979. Accomplishment of the replacement constitutes terminating action for the repetitive inspections required by paragraph (a) of this AD. \n\n\t\t(1)\tRemove any inboard wheel half specified in paragraph (b) of this AD, and replace it with an inboard wheel half having P/N 2607046, S/N 5899 or greater, or S/N H-1722 or greater. And \n\n\t\t(2)\tRemove any outboard wheel half specified in paragraph (b) of this AD, and replace it with an outboard wheel half having P/N 2607047, S/N B-5899 or greater, or S/N H-0864 or greater. \n\n\t(c)\t(1)\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\t(c)\t(2)\tAlternative methods of compliance, approved previously in accordance with AD 97-17-01, amendment 39-10102, are approved as alternative methods of compliance with this AD. \n\n\tNOTE 3: Information concerning the existence ofapproved alternative methods of compliance with this AD, if any, may be obtained from the Seattle ACO. \n\n\t(d)\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(e)\tExcept as provided by paragraph (a)(2) of this AD, the actions shall be done in accordance with Bendix Service Information Letter 392, Revision 1, dated November 15, 1979; Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988; or Allied Signal Service Bulletin No. 737-32-026, dated June 27, 1998, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1998, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988; which contains the following list of effective pages: \n\n\t Shownon Page \n\n\n\nPage Number\nRevision Level \nShown on Page \nDate\nShown on Page \n1-6 \nOriginal \nJune 27, 1988\n\n\nAttachment 1 \n7-14 \nOriginal\nJanuary 17, 1978 \n\n\nAttachment 2 \n15\nOriginal\nJune 27, 1988\n\n\t\t(1)\tThe incorporation by reference of Allied Signal Service Bulletin 737-32-026, dated June 27, 1988, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988, is 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 Bendix Service Information Letter 392, Revision 1, dated November 15, 1979; and Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988; was approved previously by the Director of the Federal Register as of September 16, 1997 (62 FR 43067, August 12, 1997). \n\n\t\t(3)\tCopies may be obtained from Allied Signal Aerospace Company, Bendix Wheels and Brakes Division, South Bend, Indiana 46624; and Bendix Aircraft Brake and StrutDivision, 3520 Westmoor Street, South Bend, Indiana 46628-1373. 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(f)\tThis amendment becomes effective on February 8, 1999.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 97-17-01, amendment 39-10102 (62 FR 43067, August 12, 1997), which is applicable to certain Boeing Model 737-100 and -200 series airplanes, was published in the Federal Register on July 9, 1998 (63 FR 37072). The action proposed to continue to require replacement of certain outboard and inboard wheel halves with improved wheel halves; cleaning and inspecting certain outboard and inboard wheel halves for corrosion, missing paint in large areas, and cracks; and repair or replacement of the wheel halves with serviceable wheel halves, if necessary. The action also proposed to require that the actions be accomplished in accordance with revised service information. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the three comments received. \n\n\tThe commenters support the proposed rule. \n\nExplanation of Changes Made to this Final Rule \n\n\tThe notice of proposed rulemaking (NPRM) references Allied Signal Service Bulletin No. 737-32-026, dated June 27, 1998, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988, as the appropriate source of service information for accomplishment of the actions specified in paragraph (a)(1) of the NPRM. However, the FAA intended to give credit to any operator that may have accomplished the actions previously in accordance with Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988 (which was referenced as the appropriate source of service information for accomplishment of certain actions in AD 97-17-01). Reference to Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988, was inadvertently omitted from paragraph (a)(1) of the NPRM. Therefore, the FAA has revised the final rule to specify that accomplishment of the actions specified in paragraphs(a)(1)(i), (a)(1)(ii), and (a)(1)(iii) of this AD in accordance with Allied Signal Service Bulletin No. 737-32-026, dated April 26, 1988, or Allied Signal Service Bulletin No. 737-32-026, dated June 27, 1988, including Attachment 1, dated January 17, 1978, and Attachment 2, dated June 27, 1988; prior to the effective date of this AD; is acceptable for compliance with the applicable requirements of this AD. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the change described previously. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 634 Model 737-100 and -200 series airplanes of the affected design in the worldwide fleet. The FAA estimates that 241 airplanes of U.S. registry will be affected by this AD.Because this AD merely requires that the actions currently required by AD 97-17-01 be accomplished in accordance with revised service information, the AD adds no additional costs and requires no additional work to be performed by affected operators. The current costs associated with this amendment are reiterated in their entirety (as follows) for the convenience of affected operators. \n\n\tThe FAA estimates that it will take approximately 4 work hours per airplane to accomplish the required replacement of wheel halves, at an average labor rate of $60 per work hour. Required parts will cost approximately $20,212 per airplane. Based on these figures, the cost impact of the required replacement on U.S. operators is estimated to be $4,928,932, or $20,452 per airplane. \n\n\tThe FAA also estimates that it will take approximately 2 work hours per airplane to accomplish the required cleaning and inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the required cleaning and inspection on U.S. operators is estimated to be $28,920, or $120 per airplane. \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\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 FlexibilityAct. 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\n List 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: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by removing amendment 39-10102 (62 FR 43067, August 12, 1997), and by adding a new airworthiness directive (AD), amendment 39-10967, to read as follows: