AD 2009-24-07

We are adopting a new airworthiness directive (AD) for certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. This AD requires repetitive lubrications of the right and left main landing gear (MLG) forward trunnion pins. This AD also requires an inspection for discrepancies of the transition radius of the MLG forward trunnion pins, and corrective actions if necessary. For certain airplanes, this AD also requires repetitive detailed inspections for discrepancies (including finish damage, corrosion, pitting, and base metal scratches) of the transition radius of the left and right MLG trunnion pins, and corrective action if necessary. Replacing or overhauling the trunnion pins terminates the actions required by this AD. This AD results from a report that the protective finishes on the forward trunnion pins for the left and right MLG might have been damaged during final assembly. We are issuing this AD to prevent stress corrosion cracking of the forward trunnion pins, which could result in fracture of the pins and consequent collapse of the MLG.

Final rule.

2009-24-07 Boeing: Amendment 39-16095. Docket No. FAA-2009-0411; Directorate Identifier 2008-NM-190-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective January 4, 2010. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to Boeing Model 737-600, -700, -700C, and - 800 series airplanes, certificated in any category; as identified in Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008. \n\nSubject \n\n\t(d) Air Transport Association (ATA) of America Code 32: Landing gear. \n\nUnsafe Condition \n\n\t(e) This AD results from a report indicating that the protective finishes on the main landing gear (MLG) forward trunnion pins might have been damaged during final assembly. We are issuing this AD to prevent stress corrosion cracking of the forward trunnion pins, which could result in fracture of the pins and consequent collapse of the MLG. \n\nCompliance \n\n\t(f) Comply with this AD within the compliance times specified, unless already done. \n\nLubrication \n\n\t(g) Within 30 days after the effective date of this AD: Lubricate the left and right MLG forward trunnion pins in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008. Repeat the lubrication at intervals not to exceed 30 days until all applicable requirements of paragraph (h) of this AD have been accomplished. \n\nInspection and Corrective Actions \n\n\t(h) Within 60 months after the date of issuance of the original airworthiness certificate or date of issuance of the original export certificate of airworthiness, or within 6 months after the effective date of this AD, whichever occurs later: Except as provided by paragraph (j) of this AD, do a detailed inspection for discrepancies (including finish damage, corrosion, pitting, and base metal scratches) of the transition radius of the left and right MLG trunnion pins, in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008. Except as provided by paragraph (j) of this AD, at the times specified in paragraph 1.E., "Compliance,'' of the service bulletin, do all applicable repetitive inspections and corrective actions, in accordance with the service bulletin. Accomplishing the detailed inspections (initial and repetitive) and all applicable corrective actions specified in this paragraph terminates the repetitive lubrication requirements of paragraph (g) of this AD. \n\nNo Report Required \n\n\t(i) Although Boeing Special Attention Service Bulletin 737-32- 1402, dated August 6, 2008, specifies to send inspection reports to the manufacturer, this AD does not include that requirement. \n\nOptional Terminating Action \n\n\t(j) Overhauling or replacing a trunnion pin in accordance with the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008, ends the repetitive lubrication requirements of paragraph (g) of this AD, and the actions required by paragraph (h) of this AD, for that pin. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(k)(1) The Manager, Seattle Aircraft Certification Office (ACO), FAA, has the authority to approve AMOCs for this AD, if requested using the procedures found in 14 CFR 39.19. Send information to Attn: Nancy Marsh, Aerospace Engineer, Airframe Branch, ANM-120S, FAA, Seattle ACO, 1601 Lind Avenue, SW., Renton, Washington 98057- 3356; telephone (425) 917-6440; fax (425) 917-6590. Or, e-mail information to 9-ANM-Seattle-ACO-AMOC-Requests@faa.gov. \n\t(2) To request a different method of compliance or a different compliance time for this AD, follow the procedures in 14 CFR 39.19. Before using any approved AMOC on any airplane to which the AMOC applies, notify your principal maintenance inspector (PMI) or principal avionics inspector (PAI), as appropriate, or lacking a principal inspector, your local Flight Standards District Office. The AMOC approval letter must specifically reference this AD. \n\t(3) An AMOC that provides an acceptable level of safety may be used for any repair required by this AD, if it is approved by an Authorized Representative for the Boeing Commercial Airplanes Delegation Option Authorization Organization who has been authorized by the Manager, Seattle ACO, to make those findings. For a repair method to be approved, the repair must meet the certification basis of the airplane and the approval must specifically refer to this AD. \n\nMaterial Incorporated by Reference \n\n\t(l) You must use Boeing Special Attention Service Bulletin 737- 32-1402, dated August 6, 2008, to do the actions required by this AD, unless the AD specifies otherwise. If you accomplish the optional terminating action specified in this AD, you must use Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008, to do those actions, unless the AD specifies otherwise. \n\t(1) The Director of the Federal Register approved theincorporation by reference of this service information under 5 U.S.C. 552(a) and 1 CFR part 51. \n\t(2) For service information identified in this AD, contact Boeing Commercial Airplanes, Attention: Data & Services Management, P.O. Box 3707, MC 2H-65, Seattle, Washington 98124-2207; telephone 206-544-5000, extension 1; fax 206-766-5680; e-mail me.boecom@boeing.com; Internet https://www.myboeingfleet.com. \n\t(3) You may review copies of the service information at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington. For information on the availability of this material at the FAA, call 425-227-1221 or 425-227-1152. \n\t(4) You may also review copies of the service information that is incorporated by reference at the National Archives and Records Administration (NARA). For information on the availability of this material at NARA, call 202-741-6030, or go to: http:// www.archives.gov/federal_register/code_of_federal_regulations/ ibr_locations.html.

Discussion \n\n\tWe issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an airworthiness directive (AD) that would apply to certain Boeing Model 737-600, -700, -700C, and -800 series airplanes. That NPRM was published in the Federal Register on May 5, 2009 (74 FR 20661). That NPRM proposed to require repetitive lubrications of the right and left main landing gear (MLG) forward trunnion pins. That NPRM also proposed to require an inspection for discrepancies of the transition radius of the MLG forward trunnion pins, and corrective actions if necessary. For certain airplanes, that NPRM also proposed to require repetitive detailed inspections for discrepancies (including finish damage, corrosion, pitting, and base metal scratches) of the transition radius of the left and right MLG trunnion pins, and corrective action if necessary. Replacing or overhauling the trunnion pins would terminate the actions proposed by that NPRM. \n\nComments \n\n\tWe gave the public the opportunity to participate in developing this AD. We considered the comments received from the commenters. \n\nSupport for the NPRM \n\n\tBoeing and Alaska Airlines support the NPRM. \n\nRequest To Change Reference to Terminating Action in Paragraph (h) of the Final Rule \n\n\tAir Transport Association (ATA), on behalf of its member AirTran, states that paragraph (h) of the NPRM should refer to paragraph (j) of the NPRM instead of paragraph (i) of the NPRM as the optional terminating action. \n\tWe agree that paragraph (h) of the NPRM should reference paragraph (j) of the NPRM. We have changed this final rule accordingly. \n\nRequest To Clarify Service Information \n\n\tATA, on behalf of its member AirTran, states that Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008 (the source of service information cited in the NPRM), contains two errors. AirTran notes a discrepancy between the part number cited in the materials section of theservice bulletin and the Work Instructions. AirTran states that the section titled "Parts and Materials Supplied by the Operator'' of the service bulletin identifies BMS3-26 as "grease--aircraft general purpose.'' However, AirTran notes that BMS3- 26 is a corrosion-inhibiting compound, and the work instructions for the lubrication requirement identify Boeing specification BMS3-33 for the grease. In addition, the materials section of the service bulletin identifies MS20995NC32 (corrosion-resistant steel). AirTran requests that we provide clarification regarding the correct safety wire to be used for the trunnion pin installation to ensure consistent fleet compliance. \n\n\tWe agree that the information on page 23 of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008, under the heading "Parts and Materials Supplied by the Operator'' contains errors. However, this section of the service bulletin is not mandated by the AD; therefore, no change to the AD is necessary. We have requested that Boeing issue an information notice to clarify the intent of the service bulletin. We have not changed the AD in this regard. \n\nRequest To Not Require the Use of Ultrachromate 300 \n\n\tContinental Airlines notes that Part 3 of the Accomplishment Instructions of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008, specifies the use of Ultrachromate 300. Continental Airlines states that this chemical is a known carcinogen that requires special handling precautions and states that using this chemical is better suited in a landing gear shop environment where adequate safety precautions are in place. Furthermore, Continental Airlines states there is a risk that using Ultrachromate 300 could contaminate the surrounding landing gear structures. The commenter requests that we revise the NPRM to require applying primer and paint with repetitive lubrications as sufficient protection against corrosion. The commenter notes that it has overhauled 64 landing gear sets on Boeing Model 737-700 and -800 series airplanes, and has not received any reports of corrosion findings on the transition radius of the forward trunnion pins. \n\tWe disagree that applying primer and paint in combination with repetitive lubrications provides sufficient protection against corrosion for all affected airplanes. Ultrachromate 300 or equivalent is used to ensure that the primer adheres properly. We agree that appropriate precautions should be taken when handling Ultrachromate 300. The procedure for using Ultrachromate 300 was developed with operator input during an all-operator meeting held in Seattle on November 6, 2007. We have not changed this AD in this regard. Operators who wish to use an alternative procedure may request approval of an AMOC following the procedures outlined in paragraph (k) of this AD. \n\nRequest To Extend Compliance Time \n\n\tContinental Airlines notes that Boeing currently has no forward trunnion pins in stock, and the lead time for this part is 175 days. Continental Airlines states that it is concerned that the unavailability of parts could severely impact its ability to perform the inspection within the proposed time limits. \n\tWe infer that Continental Airlines is requesting that we extend the compliance time. We do not agree to extend the compliance time. In developing an appropriate compliance time for this action, we considered the urgency associated with the subject unsafe condition, the availability of required parts, and the practical aspect of accomplishing the required modification within a period of time that corresponds to the normal scheduled maintenance for most affected operators. According to the manufacturer, an ample number of required parts will be available to modify the U.S. fleet within the proposed compliance time. We have not changed this AD in this regard. However, according to the provisions of paragraph (k) of the final rule, we may approve requests to adjust the compliance time if the request includes data that prove that the new compliance time would provide an acceptable level of safety. \n\nRequest To Clarify Magnification Requirements \n\n\tATA, on behalf of its member AirTran, also states that Part I, step 5, of the Work Instructions of Boeing Special Attention Service Bulletin 737-32-1402, dated August 6, 2008, allows for a range of magnification from unaided to up to 10X magnification. AirTran questions the reason for specifying a range of the magnification and requests that we change the NPRM to require a specific level of magnification to ensure consistent fleet compliance. \n\tWe do not agree to limit the choice provided by the service bulletin. We have determined that using any of the magnification levels specified in the service bulletin provides an adequate level of safety. We have not changed the final rule in this regard. \n\nConclusion \n\n\tWe reviewed the relevant data, considered the comments received, and determined that air safety and the public interest require adopting the AD with the change described previously. We also determined that this change will not increase the economic burden on any operator or increase the scope of the AD. \n\nCosts of Compliance \n\n\tWe estimate that this AD affects 100 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tTable--Estimated Costs\n\n\n\nAction\nWork hours\nAverage labor rate per hour\nParts\nCost per product\nNumber of U.S.-registered airplanes\nFleet cost\nRepetitive lubrication\n1\n$80\n$0\n$80\n100\n$8,000\nInspections\n8\n$80\n$0\n$640 per inspection cycle\n100\n$64,000 per inspection cycle\n\nAuthority for This Rulemaking \n\n\tTitle 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. "Subtitle VII: Aviation Programs,'' describes in more detail the scope of the Agency's authority. \n\tWe are issuing this rulemaking under the authority described in "Subtitle VII, Part A, Subpart III, Section 44701: General requirements.'' Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action. \n\nRegulatory Findings \n\n\tThis AD will not have federalism implications under Executive Order 13132. This AD 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. \n\tFor the reasons discussed above, I certify that this AD: \n\t(1) Is not a "significant regulatory action'' under Executive Order 12866, \n\t(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979), and \n\t(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. \n\tYou can find our regulatory evaluation and the estimated costs of compliance in the AD Docket. \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\nAccordingly, under the authority delegated to me by the Administrator, the FAA amends 14 CFR part 39 as follows: \n\nPART 39--AIRWORTHINESS DIRECTIVES \n\n1. 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\n2. The FAA amends Sec. 39.13 by adding the following new AD: