The FAA proposed to amend 14 CFR Part 39 with an AD for certain Boeing Model 747-400, -400D, and -400F series airplanes. That action, published in the Federal Register on September 7, 2004 (69 FR 54060), proposed to require replacing at least one flap control unit (FCU) in the main equipment center with a new or modified FCU. \n\nComments \n\n\tWe provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD. \n\nAgrees With Proposed AD \n\n\tOne commenter agrees with the proposed AD. \n\nRequest To Reduce the Compliance Time \n\n\tOne commenter requests that the compliance time specified in paragraph (f)(1) of the proposed AD be reduced. The commenter states that the 60-month compliance time is too long and should be shortened substantially due to the potential severity of the situation (i.e., landing without flaps) and the nature of the proposed modifications. The commenter believes that the availability of parts necessary to complete the modifications is not an issue. \n\n\tThe FAA does not agree to reduce the compliance time specified in paragraph (f)(1) of the final rule. In developing the compliance time for this AD, we considered the average utilization rate of the affected fleet, the practical aspects of an orderly modification of the fleet during regular maintenance periods, and the availability of required parts as well as the safety implications of the identified unsafe condition. In addition, the low probability of the identified unsafe condition occurring (disengagement of all three flap control units (FCU) causing loss of primary flaps control and flaps indication display) and the existing operational manual bulletin that provides guidance to the crew for extending the flaps in alternate mode in the absence of indication are consistent with longer compliance times. Based on these factors, the proposed compliance time of 60 months afterthe effective date of the final rule was determined to be appropriate. Further, we arrived at the proposed compliance time with manufacturer concurrence. We have not changed the final rule in this regard. \n\nRequest To Remove Paragraph (g) of the Proposed AD \n\n\tOne commenter requests that paragraph (g) of the proposed AD be removed. The commenter states that paragraph (g) of the proposed AD would require actions specified in Boeing Service Bulletin 747-27-2319, dated January 24, 1991, to be done before or concurrently with paragraph (f) of the proposed AD. The commenter notes that the actions in paragraph (f) of the proposed AD are to be done according to Boeing Alert Service Bulletin 747-27A2386, dated March 13, 2003, and that the alert service bulletin specifies in paragraph 1.B. that "you cannot make the changes in this service bulletin unless the changes given in Boeing Service Bulletin 747-27-2319 are made." Thus, the commenter believes there is no need for paragraph (g) of the proposed AD. \n\n\tWe do not agree to remove paragraph (g) of the final rule. We agree that paragraph (f) of the final rule requires the actions to be done "in accordance with the Accomplishment Instructions of Boeing Alert Service Bulletin 747-27A2386, dated March 13, 2003" and that paragraph 1.B. of the alert service bulletin refers to the concurrent actions that are specified in paragraph (g) of the final rule. However, paragraph 1.B. of the alert service bulletin precedes the Accomplishment Instructions of the alert service bulletin. Because the Accomplishment Instructions of the alert service bulletin do not specify to do any concurrent action, paragraph (g) of the final rule is needed to clarify that the concurrent action must be done. We have not changed the final rule in this regard. \n\nRequest for Clarification of Test \n\n\tOne commenter points out that paragraph 3.B.2. of the Boeing Alert Service Bulletin 747-27A2386 specifies that a built-in test equipment (BITE) test be done according to Chapter 27-51-51 of the Boeing 747-400 airplane maintenance manual (AMM). The commenter notes that there is no BITE test in either 27-51-00/501 or 27-51-51/401 of the Boeing 747-400 AMM. The commenter contends the alert service bulletin refers to a test that does not exist and is not necessary. The commenter also states that the alert service bulletin specifies installing the FCU in accordance with Chapter 27-51-51 of the Boeing 747-400 AMM and that the referenced AMM specifies to do an operational test of the FCU that includes both a central maintenance computer initiated ground test and exercising the flaps through full travel to ensure proper operation and indication. \n\n\tWe infer from the comment that the commenter requests that the reference to the BITE test be clarified. We partially agree. We acknowledge that paragraph 3.B.2. of the alert service bulletin specifies a BITE test be done according to Chapter 27-51-51 of the Boeing 747-400 AMM. However, Chapter 27-51-51 of the Boeing 747-400 AMM refers to a BITE test only in the summary of the AMM procedure, but not within the body of the AMM procedure. Within the body of the AMM procedure, there is a "GROUND TEST," under the heading "OPERATIONAL TEST," that is to be done following installation of the FCU. Although the nomenclature within the Boeing documents may seem inconsistent, we consider the "GROUND TEST" specified in Chapter 27-51-51 of the Boeing 747-400 AMM to be part of the FCU BITE test. Furthermore, Chapter 27-51-51 of the Boeing 747-400 AMM includes all necessary testing that must be done following installation of a new FCU. In addition, because the final rule references only the alert service bulletin, there is no need to add a clarification of the BITE test to the final rule. We have not changed the final rule in this regard. \n\nConclusion \n\n\tWe have carefully reviewed the available data, including the comments that have been submitted, and determined that air safety and the public interest require adopting the AD as proposed. \n\nCosts of Compliance \n\n\tThere are about 614 airplanes of the affected design worldwide. This AD will affect about 87 airplanes of U.S. registry. The following tables provide the estimated costs for U.S. operators to comply with this AD. \n\n\nReplacement \nWork hours \nAverage labor rate per hour \nParts \nCost per airplane \n\n\n\n\nEstimated Costs \nWith new -208 FCU With modified -208 FCU \n2 \n10 \n$65 \n65 \n$78,550 \n975 \n$78,680 \n1,625 \n\n\n\n\nEstimated Concurrent Service Bulletin Costs \nWith new -207 FCU With modified -207 FCU \n3 87 \n65 65 \n235,650 2,925 \n235,845 \n8,580 \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\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\tWe have determined that this 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\n\tFor the reasons discussed above, I certify that this AD: \n\n\t(1) Is not a "significant regulatory action" under ExecutiveOrder 12866; \n\n\t(2) Is not a "significant rule" under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and \n\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\n\tWe prepared a regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation. \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 airworthiness directive (AD):