On February 12, 1998, the FAA issued priority letter AD 98-04-40 (FAA Docket 98-SW-09-AD), applicable to Eurocopter France Model SA.315B, SA.316B, SA.316C, SA.319B, and SE.3160 helicopters. That AD was published in the Federal Register on April 17, 1998 (63 FR 19183). That AD requires, for blades with 400 or more hours time-in-service (TIS), within 25 hours TIS, inspecting each blade spar for cracks using a dye-penetrant method, and visually inspecting each blade cuff for cracks using a 10-power or higher magnifying glass. If a crack is discovered in either a blade spar or cuff, removal and replacement of the blade with an airworthy blade is required prior to further flight. That action was prompted by an accident in which a Model SA.315B helicopter lost a main rotor blade (blade) just prior to take-off. Although the main gearbox and the remainder of the main rotor assembly separated from the helicopter and passed through the cockpit, there were no fatalities. The cause of the blade failure was determined to be fatigue cracks that originated from the outboard blade-to-cuff attachment bolt hole and progressed through the blade spar and cuff. That condition, if not corrected, could result in separation of a blade and subsequent loss of control of the helicopter. Priority Letter AD 98-10-09 issued May 6, 1998, superseded AD 98-04-40. AD 98-10-09 requires the same one-time inspections as required by AD 98-04-40, but also requires, at intervals not to exceed 25 hours TIS, a recurring visual inspection of the blade spar at the outboard blade-to-cuff attachment bolt hole for cracks using a 10-power or higher magnifying glass. \n\n\tThe FAA has reviewed Eurocopter France Service Telex No. 00055/0034/98, dated February 3, 1998 (Eurocopter Service Telex: 316/319 No. 01.64 and 315 No. 01.29), which describes procedures for inspecting each blade spar for cracks using a dye-penetrant method, and visually inspecting each blade cuff for cracks using a 10-power or higher magnifying glass; and Eurocopter France Service Telex No. 00060/00099/98, dated April 9, 1998 (Eurocopter Service Telex: 316/319 No. 01.65 and 315 No. 01.30), which describes procedures for repetitively inspecting each blade spar for cracks using a 10-power or higher magnifying glass. Additionally, the Direction Generale De L'Aviation Civile, which is the airworthiness authority for France, has issued AD 98-088-055(A) and 98-089-038(A), both dated February 25, 1998; and AD 98-170-056(A)R1 and 98-171-039(A)R1, both dated May 6, 1998, to mandate these actions. \n\n\tSince the unsafe condition described is likely to exist or develop on other Eurocopter France Model SA.315B, SA.316B, SA.316C, SA.319B, and SE.3160 helicopters of the same type design, the FAA issued priority letter AD 98-10-09 to prevent separation of a blade and subsequent loss of control of the helicopter. This AD requires, for blades with 400 or more hours time-in-service (TIS), within 25 hours TIS, inspecting each blade spar for cracks using a dye-penetrant method, and visually inspecting each blade cuff for cracks using a 10-power or higher magnifying glass; and thereafter, visually inspecting each blade spar with a 10-power or higher magnifying glass at intervals not to exceed 25 hours TIS. If a crack is discovered in either a blade spar or cuff, removal and replacement of the blade with an airworthy blade is required prior to further flight. The actions are required to be accomplished in accordance with the service telexes described previously. \n\n\tSince it was found that immediate corrective action was required, notice and opportunity for prior public comment thereon were impracticable and contrary to the public interest, and good cause existed to make the AD effective immediately by individual letters issued on May 6, 1998 to all known U.S. owners and operators of Eurocopter France Model SA.315B, SA.316B, SA.316C, SA.319B, and SE.3160 helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to section 39.13 of the Federal Aviation Regulations (14 CFR 39.13) to make it effective to all persons. The FAA has made two non-substantive changes to the Priority Letter AD which will neither increase the economic burden on an operator nor increase the scope of the AD. The 400 or more hours TIS threshold provision has been moved from the compliance paragraph to the applicability paragraph. Additionally, Figure 1 has been enhanced to provide a clearer picture of the affected blade area. \n\n\tPrevious completion of the inspections required by AD 98-04-40 constitutes compliance with the initial blade inspections required by this AD. The recurring visual inspections specified in this AD shall begin on or before 25 hours TIS after the initial inspections required by either this AD or AD 98-04-40, whichever occurred first. If more than 25 hours TIS has elapsed since the inspections required by AD 98-04-40, then the recurring visual inspection specified in this AD must be accomplished prior to further flight. \n\n\tThe FAA estimates that 106 helicopters of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per helicopter to inspect a blade and 4 work hours to replace a main rotor blade, if necessary, and that the average labor rate is $60 per work hour. Required parts will cost approximately $49,700 per blade. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $5,319,080 for the first year, assuming one blade replacement per helicopter and $25,440 each subsequent year, assuming five inspections per year and no blade replacements. \n\nComments Invited \n\tAlthough this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications should identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed. \n\n\tComments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket. \n\n\tCommenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 98-SW-23-AD." The postcard will be date stamped and returned to the commenter. \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\tThe FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatoryaction" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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 the Amendment \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\t1. The authority citation for part 39 continues to read as follows: \n\tAuthority:49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\t2. Section 39.13 is amended by removing Amendment 39-10479 (63 FR 19183, April 17, 1998) and by adding a new airworthiness directive Amendment 39-10725 to read as follows: