The FAA received a report of a fire in the cargo bay left sidewall at station 900 on a Boeing Model 747-400 series airplane. The fire was caused by arcing between wire bundle W4489 and the receptacle housing of the chiller boost fan, which also caused fire damage to the surrounding insulation blankets and cargo liner. In 1990, the manufacturer corrected this condition by rerouting wire bundle W4489 in the area of the chiller boost fan. However, the corrective action may not have been properly applied to certain Model 747-400 and -400D series airplanes delivered prior to and after 1990. The incorrect wire routing configuration could lead to possible interference between wire bundle W4489 and the receptacle housing of the chiller boost fan, drain tubes, and adjacent structure. This condition, if not corrected, could result in damage to the wire bundle and consequent arcing and fire. \n\nExplanation of Relevant Service Information \n\n\tThe FAA has reviewed and approved Boeing Alert Service Bulletin 747-21A2427, dated April 24, 2003, which describes procedures for inspecting to determine the routing configuration of wire bundle W4489 and related investigative/corrective actions, if necessary. The related investigative actions include a detailed inspection of wire bundle W4489 for damage; and a detailed inspection for missing wire clamps. The corrective actions include repairing any damage to wire bundle W4489; installing any missing wire clamps; and rerouting wire bundle W4489. Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. \n\nExplanation of Requirements of the Rule \n\n\tSince an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design that may be registered in the United States at some time in the future, this AD is being issued to prevent possible interference between wire bundle W4489 and the receptacle housing of the chiller boost fan, drain tubes, and adjacent structure, which could result in damage to the wire bundle and consequent arcing and fire. This AD requires an inspection to determine the routing configuration of wire bundle W4489 and related investigative/corrective actions, if necessary. The actions are required to be accomplished in accordance with the service bulletin described previously. \n\nCost Impact \n\n\tNone of the airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future. \n\n\tShould an affected airplane be imported and placed on the U.S. Register in the future, itwould require approximately 1 work hour to accomplish the required inspection, at an average labor rate of $65 per work hour. Based on these figures, the cost impact of this AD would be $65 per airplane. \n\nDetermination of Rule's Effective Date \n\n\tSince this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, prior notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register. \n\nComments Invited \n\n\tAlthough this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption ADDRESSES. All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tSubmit comments using the following format: \n\n\tOrganize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.\n\n \tFor each issue, state what specific change to the AD is being requested. \n\n\tInclude justification (e.g., reasons or data) for each request. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, bothbefore and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 2004-NM-01-AD." The postcard will be date stamped and returned to the commenter. \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) isnot 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\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 readas follows: \n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n2. Section 39.13 is amended by adding the following new airworthiness directive: