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 747 series airplanes was published in the Federal Register on April 16, 2003 (68 FR 18565). That action proposed to require identification of the valves installed on the engine struts as hydraulic supply (fire) shutoff valves for the engine-driven pump, corrective action if necessary, and eventual replacement of discrepant valves with serviceable parts. \n\nComments \n\n\tInterested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nSupport for Proposed AD \n\n\tTwo commenters support the proposed AD. \n\nRequest To Add Certain Part Numbers (P/N) for Valve Replacement \n\n\tOne commenter requests that the proposed AD be revised to include hydraulic supply (fire) shutoff valves, P/Ns 10-3200-1 and 10-3200-2. The commenter states that these additional valves are not manufactured by Circle Seal and should be acceptable replacements. This would provide operators with more options when replacing a discrepant Circle Seal valve. \n\n\tThe FAA agrees. Boeing maintenance drawings permit installation of valve P/Ns 10-3200-1 and 10-3200-2, and Boeing has agreed that those parts are acceptable for replacement of the discrepant Circle Seal valves. In addition, we have determined that those valves do not have the identified unsafe condition. Therefore, we have revised paragraphs (b)(1)(ii) and (b)(3) of this final rule to include valves, P/Ns 10- 3200-1 and 10-3200-2, as acceptable replacements for the discrepant Circle Seal valves. Operators should note that Boeing did not include those valves in Boeing Alert Service Bulletin 747-29A2102, dated June 29, 2000 (which was referenced in the proposed AD as the appropriate source of service information for the inspection and corrective actions), because they are easily damaged by improper engine shut down procedures. Such damage necessitates unscheduled replacement of the valves with serviceable valves of the same design or modified valves having design features, which help prevent such damage. These design features were incorporated in valve P/Ns 10-3200-3 and 10-3200-5 (specified in the service bulletin and proposed AD as the appropriate P/N for the replacement valve). \n\nRequest To Allow Repetitive Valve Tests Instead of Terminating Replacement \n\n\tThe same commenter requests that the proposed AD be revised to allow operators to continue performing the hydraulic supply (fire) shutoff valve test after four years from valve identification date. The commenter asserts that operational valve replacement should not have a mandatory replacement timetable of four years, and that the option to replace or continue repetitive testing should be left up to the operator to decide. \n\n\tWe do not agree. The Circle Seal valves having P/N S270T010-3 have a known design defect. The failure mode in these valves is not a function of time or number of flight cycles. We can better ensure long- term continued operational safety by modifications or design changes to remove the source of the problem, rather than by repetitive inspections/testing. Long-term inspections/testing may not provide the degree of safety necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous repetitive inspections, has led us to consider placing less emphasis on special procedures and more emphasis on design improvements. No change to the final rule is necessary in this regard. \n\nRequest To Revise Paragraph (b)(1)(ii) of Proposed AD \n\n\tAnother commenter, the airplane manufacturer, requests that we revise paragraph (b)(1)(ii) of the proposed AD. The commenter states that paragraph (b)(1)(ii) of the proposed AD does not allow replacement of an inoperative valve with a valve, P/N S270T010-3, because that paragraph only refers to paragraph 3.I. of the Accomplishment Instructions of Boeing Alert Service Bulletin 747-29A2102. However, paragraph (c) of the proposed AD specifies that a valve, P/N S270T010- 3, may be installed if requirements of the AD are accomplished. \n\n\tWe agree. It was our intention to allow a valve, P/N S270T010-3, to be installed if a P/N 10-3200-3 or 10-3200-5 is not available and to allow the valve to remain installed (until replacement per paragraph (b)(3) of the AD) as long as it continues to pass the repetitive hydraulic supply (fire) shutoff valve test, per paragraph 3.J. of the Accomplishment Instructions of Boeing Alert Service Bulletin 747- 29A2102. Therefore, we have revised paragraph (b)(1)(ii) of this final rule to allow operators to install a valve, P/N S270T010-3, as a replacement as long as the repeated testing is performed per paragraph 3.J. of the service bulletin in accordance with paragraph (b)(2) of this final rule.Request To Revise Preamble and Paragraph (e) of Proposed AD \n\n\tThe same commenter requests that we make the following changes to the preamble and paragraph (e) of the proposed AD: \n\nIn the "Discussion" section in the preamble of the proposed AD, identify the model for which the reports indicating malfunctioning valves were received and on which the failure mode was discovered during production testing as Boeing Model 737, 757, and 767 series airplanes, not Model 747 series airplanes. The commenter explains that no reports were received on Model 747 airplanes. \nIn paragraph (e) of the proposed AD, omit the duplicate reference to the "sections." \n\n\tWe partially agree with the commenter's requests: \n\nWe agree that the models for which the original malfunctioning valve reports on which the failure mode was discovered were Model 737, 757, and 767 series airplanes--not Model 747 series airplanes. However, the "Discussion" section is not restated in this final rule, and, therefore,no change to the final rule is necessary in this regard. \nWe do not agree that the second reference to the "sections" in paragraph (e) of the proposed AD has been duplicated. The parenthetical reference to sections 21.197 and 21.199 of the Federal Aviation Regulations provides the full Code of Federal Regulations citation for those sections, which is the legal citation. No change to the final rule is necessary in this regard. \n\n\nExplanation of Change Made to the Cost Impact Section of the Final Rule \n\n\tBecause the cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD, we have revised the Cost Impact section of this final rule to specify an estimate of four work hours for the valve replacement instead of the estimated six work hours specified in the proposed rule for that action. The six work hours specified in the proposed rule included incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions. Those costs are not typically included in AD rulemaking actions. \n\nConclusion \n\n\tAfter careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes previously described. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nChanges to 14 CFR Part 39/Effect on the AD \n\n\tOn July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's airworthiness directives system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. However, for clarity and consistency in this final rule, we have retained the language of the NPRM regarding that material. \n\nChange to Labor Rate \n\n\tWe have reviewed the figures we have used over the past several years to calculate AD costs to operators. To account for various inflationary costs in the airline industry, we find it necessary to increase the labor rate used in these calculations from $60 per work hour to $65 per work hour. The cost impact information, below, reflects this increase in the specified hourly labor rate. \n\nCost Impact \n\n\tThere are approximately 681 airplanes of the affected design in the worldwide fleet. The FAA estimates that 130 airplanes of U.S. registry will be affected by this AD, that it will take approximately 1 work hour per airplane to identify the valve, and that the average labor rate is $65 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $8,450, or $65 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\tReplacing a valve, if required, will take approximately 4 work hours, at an average labor rate of $65 per work hour. Required parts and hydraulic fluid will cost approximately $4,438 per valve. Based on these figures, the cost impact of replacing a valve is estimated to be $4,698. \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, itis 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. \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 read as 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: