AD 2009-09-07

We are adopting a new airworthiness directive (AD) for all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. For all airplanes, this AD requires repetitive overhaul of the retract actuator beam of the main landing gear (MLG). For certain airplanes, this AD requires repetitive inspections for damage of the retract actuator beam, and related investigative and corrective actions if necessary. This AD results from reports of broken retract actuator beams of the MLG and the subsequent failure of the MLG to fully retract. We are issuing this AD to detect and correct broken retract actuator beams of the MLG, which could cause damage to the beam arm, hydraulic tubing, and flight control cables. Damage to the flight control cables could result in loss of control of the airplane.

Final rule.

2009-09-07 Boeing: Amendment 39-15893. Docket No. FAA-2008-1070; Directorate Identifier 2008-NM-087-AD. \n\nEffective Date \n\n\t(a) This airworthiness directive (AD) is effective June 11, 2009. \n\nAffected ADs \n\n\t(b) None. \n\nApplicability \n\n\t(c) This AD applies to all Boeing Model 737-100, -200, -200C, - 300, -400, and -500 series airplanes, certificated in any category. \n\nUnsafe Condition \n\n\t(d) This AD results from reports of broken retract actuator beams of the main landing gear (MLG) and the subsequent failure of the MLG to fully retract. We are issuing this AD to detect and correct broken retract actuator beams of the MLG, which could result in damage to the beam arm, hydraulic tubing, and flight control cables. Damage to the flight control cables could result in loss of control of the airplane. \n\nCompliance \n\n\t(e) Comply with this AD within the compliance times specified, unless already done. \n\nInspection and Related Investigative and Corrective Actions/Overhaul \n\n\t(f) Except as provided by paragraphs (g) and (h) of this AD: At the applicable times specified in paragraph 1.E. of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, inspect for damage of the retract actuator beam of the MLG and overhaul the retract actuator beam, as applicable, by doing all the applicable actions specified in the Accomplishment Instructions of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008. Do all applicable related investigative and corrective actions before further flight. Repeat the applicable inspection or overhaul thereafter at the applicable time specified in paragraph 1.E. of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008. \n\nExceptions to Service Information \n\n\t(g) Where Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, specifies a compliance time after "* * * the date on this service bulletin,'' this AD requires compliance within the specified compliance time after the effective date of this AD. \n\t(h) Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, specifies that the actions are for airplanes with new MLG retract actuator beams that have not been overhauled having part number (P/N) 65-46108-15 and subsequent dash numbers; and new or overhauled MLG retract actuator beams having P/N 65-46108-14 and previous dash numbers. However, this AD is not limited to new or overhauled beams. This AD requires that the actions required by paragraph (f) of this AD be done on airplanes with any MLG retract actuator beam having those P/Ns. \n\nAlternative Methods of Compliance (AMOCs) \n\n\t(i)(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 Aircraft Certification Office, 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. \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(j) You must use Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, to do the actions required by this AD, unless the AD specifies otherwise. \n\t(1) The Director of the Federal Register approved the incorporation 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, P.O. Box 3707, Seattle, Washington 98124-2207; telephone 206-544-9990; fax 206-766-5682; e-mail DDCS@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 all Boeing Model 737-100, -200, -200C, -300, -400, and -500 series airplanes. That NPRM was published in the Federal Register on October 8, 2008 (73 FR 58906). For all airplanes, that NPRM proposed to require repetitive overhaul of the retract actuator beam of the main landing gear (MLG). For certain airplanes, that NPRM proposed to require repetitive inspections for damage of the retract actuator beam, and related investigative and corrective actions if necessary. \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 concurs with the contents of the NPRM. \n\nRequest To Change Overhaul Requirements \n\n\tContinental Airlines (CAL) asks that we not mandate overhaul of the retract actuator beam using the instructions specified in the Accomplishment Instructions of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008. CAL states that the reason for release of Boeing Service Bulletin 737-32A1355, Revision 2, is Boeing's concern regarding shop process deficiencies at some repair facilities where correct overhaul procedures were not followed. CAL finds this reasoning detrimental to all operators that follow correct overhaul procedures at their repair facilities. \n\tCAL landing gear components, including the retract actuator beams of the left and right main landing gear, are time controlled per the Boeing 737-300/-500 Maintenance Program and are scheduled to be overhauled at 10-year intervals at an FAA-approved landing gear overhaul facility. CAL also makes the following recommendations regarding Boeing Service Bulletin 737-32A1355, Revision 2: \n\tThe stripping of all chrome and nickel plating specified in Step 4 of Figure 2 should be included as anoption, as in the Boeing 737 Component Maintenance Manual (CMM), Section 32-00-05. \n\tThe nital etch inspection of machined surfaces specified only in Step 9 of Figure 2 should not be limited to machined surfaces. \n\tThe stress relieving of the part specified in Step 10 of Figure 2 should be an optional step, as specified in Boeing 737 CMM, Section 32-00-05. \n\tThe shot peening of the entire part specified in Step 12 of Figure 2 should be limited to the machined areas of the part since the geometry of the actuator beam does not allow for effective shot peening of the entire area. \n\tA caution note for arc burns associated with grounding (similar to Step 14) should be included in Step 13 of Figure 2. \n\tWe disagree that using the instructions specified in the Accomplishment Instructions of Boeing Service Bulletin 737-32A1355, Revision 2, dated March 5, 2008, to perform the overhaul of the retract actuator beam should not be mandated. Revision 2 of Boeing Service Bulletin 737-32A1355 references improved overhaul procedures, and those procedures are required by this AD. However, according to the provisions of paragraph (i) of this AD, we may approve a request for using different overhaul procedures if the request includes data that prove that those procedures would provide an acceptable level of safety. We have not changed the AD in this regard. \n\tWe acknowledge the request for changes to Boeing Service Bulletin 737-32A1355, Revision 2. At the present time, Boeing has not issued a revised service bulletin with the changes. However, if Boeing Service Bulletin 737-32A1355, Revision 2, is revised after issuance of this AD, we might consider approving the revised service bulletin as an alternative method of compliance (AMOC) with the requirements of this AD. We have not changed the AD 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 as proposed. \n\nCosts of Compliance \n\n\tWe estimate that this AD affects 652 airplanes of U.S. registry. The following table provides the estimated costs for U.S. operators to comply with this AD. \n\n\tEstimated Costs \n\n\nAction/Airplane Group\nWork hours\nAverage labor rate per hour\nParts Cost\nCost per product\nNumber of U.S.-registered airplanes\nFleet cost\nOverhaul for Group 1; Configurations 1, 2, and 3\n64\n$80\nNone\n$5,120, per overhaul cycle\n652\n$3,338,240\nInspection for Group 1, Configuration 3\n1\n$80\nNone\n$80, per inspection cycle\n525\n$42,000\n\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\n\nSec. 39.13 (Amended) \n\n2. The FAA amends Sec. 39.13 by adding the following new AD: