On August 31, 1998, the FAA issued Priority Letter AD 98-19-04 applicable to Agusta S.p.A. Model A109C, A109E, and A109K2 helicopters, which requires conducting a tapping inspection of the upperside and lowerside of the blade tip cap for debonding between the metal shells and honeycomb core; conducting a visual inspection of the upperside and lowerside of the blade tip cap for swelling or deformation between the metal shells and the honeycomb core; and visually inspecting the welded bead along the leading edge of the blade tip cap for a crack. That action was prompted by two discoveries of cracks in the leading edge of the blade tip cap of a blade. The cracks were discovered after pilots experienced increased vibration during flight. Subsequent investigation revealed that the increased vibration was caused by debonding of the honeycomb material in the blade, which led to deformation and cracking of the blade tip cap. This condition, if not corrected, couldresult in blade tip cap failure and subsequent loss of control of the helicopter.\n \n Agusta S.p.A. has issued Agusta Bolletino Tecnico No. 109-106, dated July 21, 1998, Agusta Bolletino Tecnico No. 109EP-1, Revision A, dated September 9, 1998, and Agusta Bolletino Tecnico No. 109K-22, dated July 13, 1998, applicable to Agusta S.p.A. Model A109C, A109E, and A109K2 helicopters, which specify conducting a tapping inspection of the blade tip cap for debonding; conducting a visual inspection of the blade tip cap for swelling or deformation ; and visually inspecting the welded bead along the leading edge of the blade tip cap for a crack. The Ente Nazionale di Aviazione Civile (ENAC) classified this service bulletin as mandatory and issued AD 98-271, applicable to Model A109K2 helicopters, dated July 29, 1998; AD 98-275, applicable to Model A109C helicopters and AD 98-276, applicable to Model A109E helicopters, both dated August 4, 1998, and AD 98-319, applicable to Model A109E helicopters dated September 15, 1998, which superseded AD 98-276, in order to assure the continued airworthiness of these helicopters in Italy.\n \n These helicopter models are manufactured in Italy and are type certificated for operation in the United States under the provision of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the ENAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the ENAC, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operations in the United States.\n\n Since the unsafe condition described is likely to exist or develop on other Agusta S.p.A. Model A109C, A109E, and A109K2 helicopters of the same type design, the FAA issued Priority Letter AD 98-19-04 to prevent blade tip cap failure and subsequent loss of control of the helicopter. The AD requires, within 10 hours time-in-service (TIS), and thereafter at intervals not to exceed 25 hours TIS, conducting a tapping inspection of the upperside and lowerside of the blade tip cap for debonding between the metal shells and honeycomb core; conducting a visual inspection of the upperside and lowerside of the blade tip cap for swelling or deformation between the metal shells and the honeycomb core; and visually inspecting the welded bead along the leading edge of the blade tip cap for cracks using an 8-power or higher magnifying glass. If any crack, swelling, deformation, or debonding that exceeds the limits prescribed in the applicable maintenance manual is discovered, replacement of the blade with an airworthy blade is required. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the aircraft. Therefore, the inspections are required within 10 hours TIS, and thereafter at intervals not to exceed 25 hours TIS, and this AD must be issued immediately. \n\n Since 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 August 31, 1998 to all known U.S. owners and operators of Agusta S.p.A. Model A109C, A109E, and A109K2 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. This final rule contains three changes from the priority letter AD. Agusta issued a revision to Bolletino Tecnico No.109EP-1 on September 9, 1998, so references to it in Note 2 have been changed to reflect the revision. The Registro Aeronautico Italiano has become the ENAC, and has issued AD 98-319, dated September 15, 1998, which is applicable to Model A109E helicopters. That AD supersedes AD 98-276. This change is reflected in Note 4. Also, paragraph (a) has been changed to allow the use of a coin to conduct the tap test instead of only a steel hammer as was required in the priority letter AD. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.\n\n The FAA estimates that 21 helicopters of U.S. registry will be affected by this AD, that it will take approximately 4 work hours per helicopter to accomplish the inspection, and the average labor rate is $60 per work hour. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $5040 for the initial inspection and for each repetitive inspection of the fleet. This estimate is based on the assumption that no main rotor blade will need to be replaced as a result of these inspections.\n\nComments Invited \n Although 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 Comments 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 Commenters 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-40-AD." The postcard will be date stamped and returned to the commenter.\n \n The 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 The 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 regulatory action" 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 Air transportation, Aircraft, Aviation safety, Safety.\n\nAdoption of the Amendment\n Accordingly, 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 1. The authority citation for part 39 continues to read as follows: \n Authority: 49 U.S.C. 106(g) 40113, 44701.\n\n§ 39.13 (Amended)\n 2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: