A proposal to amend part 39 of the Federal Aviation Regulations to include an airworthiness directive (AD) that is applicable to EROS series MF10-( )-( ) full face quick donning mask regulators was published in the Federal Register on August 4, 1993 (58 FR 41441). That action proposed to require replacement of the face piece and the mask shell securing screw in accordance with EROS Service Bulletin (SB) No. MF10-35-44, and SB No. MF10-35-46, both dated June 11, 1991. \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\n\tOne commenter states that the AD should include a means for the flight crew to determine that the old masks are not defective. The FAA does not concur. The flight crew should be able to readily see whether or not the original mask is broken. The pin can be inspected in accordance with EROS SB No. MF-10-35-43, dated June 11, 1991, to determine if the mask is intact. \n\n\tOne commenter states that the compliance period should be 12 months after the effective date of this AD, as the proposed 6-month compliance period would cost operators an additional $110,000 for the purchase of additional masks to use while in the process of inspecting those masks already in service. The FAA does not concur. EROS SB No. MF10-35-44 was issued on July 15, 1991, and service data indicates that a substantial portion of the masks in service have already been inspected. The FAA believes that the proposed 6-month compliance period properly balances the needs of flight safety with operations concerns of operators. Although the NPRM stated the date of this SB as June 11, 1991, the correct date for this SB is July 15, 1991. In addition, the NPRM referred to the original version of EROS SB No. MF10-35-46, dated June 11, 1991. The correct revision and date for this SB is Revision 1, dated June 12, 1992. The final rule has been changed accordingly. \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 described previously. \n\n\tThe FAA estimates that 2,500 regulators are affected by this AD, that it will take approximately 0.5 work hours per regulators to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will cost $535 per faceplate. Based on these figures, the total cost impact of the proposed AD on U.S. operators is estimated to be $1,406,250. The manufacturer has advised the FAA, however, that it may supply the require parts at no cost, thereby reducing the total cost impact on U.S. operators. \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 amongthe 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\nList of Subjects in 14 CFR Part 39 \n\tAir Transportation, Aircraft, Aviation Safety, Incorporation by reference, Safety. \n\nAdoption of theAmendment \n\tAccordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends 14 CFR part 39 of the Federal Aviation Regulations as follows: \n\nPART 39 - AIRWORTHINESS DIRECTIVES \n\t1.\tThe authority citation for part 39 continues to read as follows: \n\tAuthority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. \n\n§39.13 - (AMENDED) \n\t2.\tSection 39.13 is amended by adding the following new airworthiness directive: