AD 2004-07-10

This amendment adopts a new airworthiness directive (AD), applicable to certain Boeing Model 737-600, -700, -700C, -800, and -900 series airplanes, that requires replacement of the proximity switch electronics unit with a new, improved unit. This action is necessary to prevent a malfunction of the aural warning for the landing gear, leading the crew to open the circuit breaker for the aural warning horn which stops the operation of other aural warnings of malfunctions in other systems and, thus, could jeopardize a safe flight and landing. This action is intended to address the identified unsafe condition.

Final rule.

2004-07-10 Boeing: Amendment 39-13554. Docket 2002-NM-101-AD. \n\n\tApplicability: Model 737-600, -700, -700C, -800, and -900 series airplanes, as listed in Boeing Alert Service Bulletin 737-32A1343, dated July 26, 2001; certificated in any category. \n\n\tCompliance: Required as indicated, unless accomplished previously.\n \n\tTo prevent a malfunction of the aural warning for the landing gear, leading the crew to open the circuit breaker for the aural warning horn which stops the operation of other aural warnings of malfunctions in other systems and, thus, could jeopardize a safe flight and landing, accomplish the following: \n\nReplacement \n\n\t(a) Within 18 months after the effective date of this AD: Remove the Proximity Switch Electronics Unit (PSEU) having part number 285A1600-2 or 285A1600-3 and replace it with a PSEU having part number 285A1600-4, per the Accomplishment Instructions of Boeing Alert Service Bulletin 737-32A1343, dated July 26, 2001. \n\nParts Installation \n\n\t(b)As of the effective date of this AD, no person shall install a PSEU having part number 285A1600-2 or 285A1600-3 on any airplane. \n\nAlternative Methods of Compliance \n\n\t(c) In accordance with 14 CFR 39.19, the Manager, Seattle Aircraft Certification Office, FAA, is authorized to approve alternative methods of compliance (AMOCs) for this AD. \n\nIncorporation by Reference \n\n\t(d) The actions shall be done in accordance with Boeing Alert Service Bulletin 737-32A1343, dated July 26, 2001. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Boeing Commercial Airplanes, 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(e) This amendment becomeseffective on May 11, 2004.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Boeing Model 737-600, - 700, -700C, -800, and -900 series airplanes was published in the Federal Register on December 31, 2003 (68 FR 75469). That action proposed to require replacement of the proximity switch electronics unit with a new, improved unit. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public. \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 890 airplanes of the affected design in the worldwide fleet. The FAA estimates that 283 airplanes of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per airplane to accomplish the required actions, and that the average labor rate is $65 per work hour. Required parts will cost approximately $40 per airplane. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $84,900, or $300 per airplane.\n \n\tThe cost impact figure discussed above is 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\n\tThe manufacturer may cover the cost of replacement parts associated with this AD, subject to warranty conditions. Manufacturer warranty remedies may also be available for labor costs associated with this AD. As a result, the costs attributable to the AD may be less than stated above. \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. \nAdoption of the Amendment \n\nAccordingly, 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\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. Section 39.13 is amended by adding the following new airworthiness directive: