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 727 and 737 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on March 26, 1997 (62 FR 14373). That action proposed to require replacement of the actuator of the engine fuel shutoff valve and the fuel system crossfeed valve with an improved actuator. That action also proposed to expand the applicability of the proposed rule by including an additional Kearfott actuator that is subject to the addressed unsafe condition. \n\nExplanation of New Service Information \n\n\tThe FAA has reviewed and approved J.C. Carter Company Service Bulletin 61163-28-09, dated May 1, 1996. Although no service bulletin revision level was designated, this new service bulletin was issued as an updated revision of the original version, dated September 28, 1995, which was referenced in the supplemental NPRM as the appropriate source of service information for accomplishment of the proposed replacement. The procedures described in these two service bulletins are essentially the same. However, the new revision includes the following additional clarifying information: \n\n\t1.\tIn Section II, Accomplishment Instructions, an additional reference to 737 Maintenance Manual (MM) 28-22-11/400 was added to the first paragraph. \n\n\t2.\tIn Section III, Materials, only two relevant changes were made. First, a new optional actuator part number, 40574-1, was added to the itemized list of part numbers. Second, information regarding the model number and nameplate of the new actuator was added to the second Note following the list of part numbers. In addition, information regarding the nameplates for Kearfott actuator models 3715-7 and 3715-8 was added to the first two headings following the Note paragraphs. \n\nComments Received \n\n\tInterested personshave been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\n\tSeveral commenters support the proposed rule. However, two other commenters suggest certain changes to the supplemental NPRM, which are discussed in the following paragraphs. \n\nRequest to Stop Issuance \n\n\tOne commenter suggests that issuance of a new AD is unnecessary for two reasons: \n\n\t1.\tThe commenter states that, "based upon the number of parts not returned to J.C. Carter to date, it appears that these parts are meeting their life requirement of 10,000 cycles." The commenter also states that, "since the clutch binding problem results in a hard failure with indication, we believe that the potential clutch binding is not a safety issue and thus, an AD is not necessary for part numbers 3715-8 and 3715-9." \n\n\tThe FAA does not concur with the commenter's statements. The FAA has determined that the fundamental issue is the improperfunctioning of certain actuators due to clutch binding, which could result in a fuel imbalance due to the inability of the flightcrew to crossfeed fuel or prevent the pilot from shutting off the fuel to the engine following an engine failure or fire. The FAA has determined that clutch binding is an identified safety issue, that an airworthiness directive is the appropriate vehicle for mandating such action to correct the unsafe condition, and that issuance of the final rule to identify such part numbers is appropriate and necessary to ensure the continued safety of the fleet. \n\n\t2.\tThis same commenter advises that part number (P/N) 3715-7 actuators had a brush-sticking problem at cold temperatures and that this problem is latent. The commenter also advises that all but 16 of such actuators have been removed from service and returned to J.C. Carter, the discrepant parts are being tracked, the locations of 14 of the 16 discrepant parts are known, and the locations of the remaining discrepant parts are being pursued for their removal from service. The commenter states that it will continue to pursue removal of P/N 3715-7 actuators from service regardless of whether an airworthiness directive is issued. \n\n\tThe FAA acknowledges that the manufacturer is continuing its efforts to remove all of the discrepant P/N 3715-7 actuators from service. However, in accordance with various bilateral airworthiness agreements with countries around the world, the FAA is obligated to advise foreign airworthiness authorities of unsafe conditions identified in products manufactured in the United States; the issuance of AD's is the means by which the FAA satisfies this obligation. Therefore, the issuance of this AD is both warranted and necessary. \n\nRequest to Reduce Number of Affected Airplanes \n\n\tThe airplane manufacturer states that J.C. Carter estimates there are only 200 Kearfott actuators that may be in service. The commenter adds that, therefore, the number of airplanesthat will require accomplishment of the AD is much lower than the 2,190 airplanes estimated in the supplemental NPRM. The FAA acknowledges that 200 actuators may be in service. However, because these actuators could be installed on any airplane in the fleet of 2,190 U.S.-registered airplanes, the FAA finds it appropriate to reflect that number in the cost impact information, below. No change to the final rule is necessary in this regard. \n\nRequest to Cite Latest Service Bulletin Revision \n\n\tOne commenter states that the updated revision of J.C. Carter Service Bulletin 61163-28-09, dated May 1, 1996, is approved by the FAA and has been released to all operators. Because this service bulletin includes the new optional actuator part number and some additional information, the commenter requests that the action required by the supplemental NPRM be accomplished in accordance with the latest service bulletin. Another commenter states that, "The release date of J.C. Carter Service Bulletin 61163-28-09 is May 1, 1996, not September 28, 1995." \n\n\tThe FAA concurs with the requests to cite the latest release of this service bulletin (described previously). The FAA has determined that the new optional actuator part does not impose any additional burden or cost on the operator. Paragraph (a) of the final rule has been changed to cite both versions of the service bulletin as appropriate sources of service information for accomplishment of the replacement. \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 change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCost Impact \n\n\tThere are approximately 4,137 Model 727 and 737 series airplanes of the affected design in the worldwide fleet. The FAA estimates that2,190 airplanes of U.S. registry will be affected by this AD, that it will take approximately 3 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Required parts would be supplied by J.C. Carter Company at no cost to operators. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $394,200, or $180 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. \n\nRegulatory Impact \n\n\tThe regulations adopted herein will not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment. \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\n List of Subjects in 14 CFR Part 39 \n\n\tAir transportation, Aircraft, Aviation safety, Incorporation by reference, Safety. \n\nAdoption of the Amendment \n\n\tAccordingly, 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\n\t1. The authority citation for part 39 continues to read as follows: Authority: 49 U.S.C. 106(g), 40113, 44701. § 39.13 (Amended) \n\t2. Section 39.13 is amended by adding the following new airworthiness directive: