The FAA proposed to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) with an AD to supersede AD 98-20-17, amendment 39-10784 (63 FR 50979, September 24, 1998). The existing AD applies to Part Number (P/N) 021929-000 (McDonnell Douglas P/N 43BO34LB02) and P/N 021904-000 (McDonnell Douglas P/N 43BO34LB03) nickel cadmium batteries manufactured prior to December 1997 that are installed on, but not limited to, McDonnell Douglas DC-9 and MD-80 aircraft, all serial numbers. The proposed AD, which is applicable to certain McDonnell Douglas transport category airplanes, was published in the Federal Register on December 14, 2004 (69 FR 74461), to require replacing all battery terminal screws, verifying that the battery contains design specification cells, and replacing the cells if the battery contains non-design specification cells. The proposed AD also proposed to require an inspection for certain nickel cadmium batteries and, if necessary, replacing battery terminal screws with new hex head bolts and adding shims. \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\nRequest for a Better Identification of the Modification \n\n\tOne commenter requests that the proposed AD provide a better way of identifying the modification. The commenter states that identifying the modification with a sticker, as specified in SAFT Mandatory Service Bulletin 01-02, Revision 2, dated August 11, 2003, makes it difficult for airlines to track compliance. The commenter notes that stickers have been known to come unglued in the presence of water, acid, and heat, all of which exist around battery locations. If a sticker becomes unglued and lost, this gives the appearance of non-compliance to the AD. The commenter suggests requiring a P/N change on the data plate by simply adding a letter to the existing P/N. \n\n\tWe do not agree that a P/N change on the data plate is necessary in this case. Although we acknowledge that stickers may come unglued, the modification sticker is merely a secondary indication of compliance. We have determined that, for the purposes of this AD, installation of a compliance sticker, as specified in SAFT Mandatory Service Bulletin 01- 02, Revision 2, dated August 11, 2003 (referenced as an additional source of service information in Boeing Alert Service Bulletin DC9- 24A195, dated December 4, 2003), is not necessary. We find that recording the installation of the modified battery in the airplane maintenance records, as required by section 91.417 of the Federal Aviation Regulations, provides an adequate means for operators to track AD compliance. Therefore, we have revised paragraph (f)(2)(ii) of this AD to specify that installing a sticker is not required. \n\nRequest to Correct Reference to Certain P/Ns \n\n\tOne commenter requests that two P/Ns be corrected. The commenter explainsthat certain P/Ns, as identified in the proposed AD, contain the letter "O" instead of the number "0." The P/Ns should be 43B034LB02 and 43B034LB03. \n\tWe agree and have revised the AD accordingly. \n\nEditorial Changes \n\n\tWe have added a new Note 2 to the AD to reiterate, as specified in the preamble of the proposed AD, that Boeing Alert Service Bulletin DC9-24A195, dated December 4, 2003, refers to SAFT Service Bulletin 01- 02, Revision 2, dated August 11, 2003, as an additional source of service information for accomplishing the modification. \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 with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD. \n\nCosts of Compliance \n\n\tThere are about 1,828 airplanes worldwide of the affected design. This AD will affect about 1,087 airplanes of U.S. registry. \n\n\tThe required inspection to determine if certain SAFT batteries are installed will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the actions specified in this AD for U.S. operators is $70,655, or $65 per airplane. \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 Executive Order 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 theRegulatory 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 removing amendment 39-10784 (63 FR 50979, September 24, 1998) and by adding the following new airworthiness directive (AD):