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 767-200 and - 300 series airplanes was published as a supplemental notice of proposed rulemaking (NPRM) in the Federal Register on June 17, 2008 (73 FR 34233). That action proposed to require replacing certain door-mounted escape slides and slide-raft assemblies with new slide-raft assemblies; replacing certain escape system latches with new latches; and modifying or replacing certain counterbalance assemblies with new counterbalance assemblies; as applicable. The supplemental NPRM also proposed to extend the compliance time, add requirements to install a longer firing cable and test the valve of the inflation trigger system of the slide- raft and, for certain airplanes, add procedures to adjust the door counterbalance systems. \n\nExplanation of Revised Service Information \n\n\tSince we issuedthe supplemental NPRM, we have reviewed Boeing Service Bulletin 767-25A0266, Revision 3, dated July 3, 2008. We referred to Boeing Service Bulletin 767-25A0266, Revision 2, dated September 27, 2007, in the supplemental NPRM as the appropriate source of service information for replacing the slide-rafts. The procedures in Revision 2 and Revision 3 are essentially the same; however, Revision 3 corrects certain typographical errors, including certain part numbers for the slide-rafts. \n\tWe have revised paragraph (a) of this AD to refer to Boeing Service Bulletin 767-25A0266, Revision 3, dated July 3, 2008, as the appropriate source of service information. We have also included Boeing Service Bulletin 767-25A0266, Revision 2, dated September 27, 2007, in Table 1 of this AD to state that actions done before the effective date of this AD in accordance with Revision 2 are acceptable for compliance with the requirements of paragraph (a) of this AD. \n\nComments \n\n\tInterested persons have beenafforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received. \n\nRequests To Withdraw Supplemental NPRM or Extend Compliance Time \n\n\tAir Transport Association (ATA), American Airlines, and Delta Airlines request that we either withdraw the supplemental NPRM or extend the compliance time for replacing the slide-rafts. All Nippon Airways requests a compliance time of 8 years (96 months), and ATA requests a compliance time of 10 years (120 months) rather than the 72 months proposed in the supplemental NPRM. \n\tATA also cites information to show the improbability of the unsafe condition, and maintains that we should withdraw the NPRM due to its lack of potential to add safety benefit, its significantly disproportional costs, its unjustified compliance period, and the fact that the intent of the proposal is already being accomplished on an attrition basis. ATA also states that if the FAA disagrees with its justifications and proceeds with the final rule, it recommends a 10- year compliance period for better correlation with risk-management methods. \n\tAmerican Airlines and ATA further object to the requirement to replace the slide-rafts. They agree with the manufacturer that the unsafe condition specified in the supplemental NPRM is not a safety issue. American Airlines and ATA state that the likelihood that the scenario described in the supplemental NPRM would result in a time- limited evacuation is extremely improbable. \n\tWe partially agree with the commenters. We do not agree with the requests to withdraw the supplemental NPRM. We have determined that an unsafe condition exists. Although the specific conditions addressed in the supplemental NPRM have not been \nencountered in service, we have received reports of partial tip-back during accidents/incidents that could have resulted in extreme tip-back given slightly different conditions, making this type of event foreseeable. During at least one of these partial tip-back events, the slides were deployed to facilitate evacuation. We do not agree that the low probability of encountering such a foreseeable event is justification to withdraw the supplemental NPRM. We have also determined that an interval based on the "useful service life'' of the slides, which is 15 years, would not address the unsafe condition in a timely manner. \n\tHowever, we do agree that it is appropriate to extend the compliance time. We have determined that a compliance time of 96 months represents an appropriate interval of time in which the required actions can be performed, while still maintaining an adequate level of safety. In developing an appropriate compliance time, we considered the safety implications, parts availability, and normal maintenance schedules for timely accomplishment of the modifications. We also considered the costs to comply with the actions (see updated cost information in the Costs of Compliance section). The revised compliance time will allow operators to offset the costs of complying with this AD with the costs associated with normal slide replacement. Therefore, we have revised paragraph (a) of this AD to extend the compliance time for replacing the slide-rafts from 72 months to 96 months. \n\nRequests To Remove Firing Cable Requirement From the Supplemental NPRM \n\n\tContinental Airlines, Goodrich, and Boeing ask that we remove paragraph (b), "Modification of the Firing Cable,'' from the supplemental NPRM. Delta points out that the requirement to modify the firing cable is proposed in Docket FAA-2008-0302 (and is now required by AD 2008-21-05, amendment 39-15689 (73 FR 59486, October 9, 2008)) at a compliance time of 36 months rather than the 72 months proposed in the supplemental NPRM. Boeing states that we should also remove the reference to Boeing Alert Service Bulletin 767-25A0395, dated August 31, 2006, from Table 1 "Previous Revisions of Service Bulletins,'' because that service bulletin relates to themodification specified in paragraph (b) of the supplemental NPRM. \n\tWe agree with the commenters' requests to remove paragraph (b) of the supplemental NPRM and the reference to Boeing Alert Service Bulletin 767-25A0395, dated August 31, 2006. The requirement to modify the firing cable is already included in AD 2008-21-05. Therefore, we have revised this AD as requested. The requirement to modify the firing cable will remain part of AD 2008-21-05, which also includes other tasks related to the firing cable. \n\nRequests To Revise Cost Impact \n\n\tGoodrich, and ATA, on behalf of its member American Airlines, request that we revise the "Cost Impact'' paragraph. American Airlines states that we did not include the cost of the slide-rafts in the original NPRM; as the slide-rafts are the dominant cost of the modification, ATA and American Airlines state that the cost estimate is both incomplete and inaccurate. Goodrich points out that the costs in the supplemental NPRM reflect prices for 2004 and requests that we revise the cost of the slide-rafts to 2008 prices. \n\tWe agree with Goodrich to revise the cost of the slide-rafts to reflect 2008 prices. The "Cost Impact'' paragraph below includes the current price of the slide-rafts. We acknowledge American Airlines' request, but point out that although the original NPRM did not include the cost of the slide-rafts, the supplemental NPRM did include those costs. \n\nRequest To Change Applicability \n\n\tBoeing requests that we change the applicability of the supplemental NPRM to refer to airplanes identified in Boeing Service Bulletin 767-25A0266, Revision 3, dated July 3, 2008, rather than referring only to those Model 767-200 and -300 series airplanes that have line numbers 1 through 793 inclusive, equipped with door-mounted escape slide systems. Boeing states that the applicability, as written in the supplemental NPRM, might make an alternative method of compliance (AMOC) request necessary for Model 767 door-mounted escapesystem part numbers that are not addressed by the proposed AD. \n\tWe agree with Boeing for the reasons stated, and have revised the applicability statement of this AD to include a reference to Boeing Service Bulletin 767-25A0266, Revision 3, dated July 3, 2008, which includes specific details about which airplanes are affected by this AD. \n\nRequests To Extend Comment Period \n\n\tDelta Airlines and ATA request additional time to review the supplemental NPRM. Delta requests that we extend the comment period for an additional 60 days because of the complex nature of the supplemental NPRM, the inclusion of multiple service bulletins, the extensive background and significant number of comments in response to the original NPRM, the hugely significant costs, and the fact that the original NPRM was thought to have been withdrawn. ATA also requests an extension of 60 days to the comment period, citing costs and the need to assess the complex requirements. \n\tWe disagree with the requests toprovide additional time to comment on the supplemental NPRM. As Delta points out in their comment, there was a period of 4.5 years between the release of the original NPRM and the supplemental NPRM, which gave operators sufficient time to consider the requirements. We have not changed the AD in this regard. \n\nRequest for Industry-Wide Response \n\n\tDelta Airlines requests that ATA coordinate an industry-wide response to the supplemental NPRM with the goal of gathering enough technical information to support its cancellation. Delta states that, given previous discussions with Boeing regarding risk and probability, the supplemental NPRM does not appear to have adequate merit. Also, given the significant cost impact, the industry would be well-served by opening the time to conduct a coordinated effort to ensure that the action proposed in the supplemental NPRM is not mandated. \n\tWe neither agree nor disagree with the request for ATA to coordinate an industry-wide response. This commentis directed to ATA and is beyond the scope of the AD action. We disagree that the supplemental NPRM does not have adequate merit. We consider the proposed actions to be an adequate response to an unsafe condition. As stated previously, although the specific conditions addressed in the supplemental NPRM have not been encountered, there have been accidents/ incidents that make this type of event foreseeable. We do not agree that the low probability of encountering such a foreseeable event is justification for withdrawing the supplemental NPRM. Therefore, we have not changed the AD in this regard. \n\tAs explained previously, we also considered the costs to comply with the actions proposed in the supplemental NPRM. While we determined that a compliance time based on the "useful service life'' of the slides would not address the unsafe condition in a timely manner, we did agree to extend the compliance time for replacing the slide-rafts from 72 months to 96 months. The revised compliance time will allow operators to offset the costs of complying with this AD with the costs associated with normal slide replacement. We have revised paragraph (a) of this AD to extend the compliance time for replacing the slide-rafts from 72 months to 96 months. \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\nCost Impact \n\n\tThere are approximately 745 airplanes of the affected design in the worldwide fleet. The FAA estimates that 261 airplanes of U.S. registry are affected by this AD. The work hours and required parts per airplane vary according to the configuration group to which the affected airplane belongs. The average labor rate is $80 per work hour. The "Cost Impact per Airplane Configuration Group'' table shows the estimated costs. \n\n\tCost Impact per Airplane Configuration Group\n\n\nAirplane configuration group \nU.S.-registered airplanes \nWork hours \nKit cost \nSlide cost \nCost per airplane \nFleet cost, by configuration group \n1 \n208 \n6 \n$1,236 \n$222,002 \n$223,718 \n$46,533,334 \n2 \n12 \n12 \n$2,472 \n$448,502 \n$451,934 \n$5,423,208 \n3 \n41 \n11 \n$98,858 \n$222,002 \n$321,740 \n$13,191,340 \n4 \n0 \n11 \n$34,012 \n$222,002 \n$256,894 \n0 \n5 \n0 \n17 \n$35,248 \n$448,502 \n$485,110 \n0 \n\n\tBased on the figures in the "Cost Impact per Airplane Configuration Group'' table, the cost impact of this AD on U.S. operators is estimated to be $65,147,882. \n\tThe cost impact figures discussed above are based on assumptions that no operator has yet accomplished any of the proposed 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\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\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 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\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\n 1. 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: