On August 15, 2006, the FAA issued Emergency AD 2006-17-51 for Agusta Model AB139 helicopters, which requires before further flight and at specified intervals, certain visual inspections of each tailpipe assembly for a crack and for overheating. If you find areas of overheating, the AD also requires, before further flight, certain inspections for damage to the surrounding structure, outside of the cowling, and inside of each tailpipe assembly in certain areas using a flashlight or a mirror and a flashlight depending on the location. The AD also requires, before further flight, if you find a crack, replacing the tailpipe assembly with an airworthy tailpipe assembly. That action was prompted by several reports of tailpipe assembly cracks. This condition, if not corrected, could result in a fire due to the structure in the cowling area overheating, separation of a part of a tailpipe assembly, and subsequent loss of control of the helicopter. \n\tThe European Aviation Safety Agency (EASA) notified us that an unsafe condition may exist on Agusta S.p.A. Model AB139 helicopters. EASA advises that the field has reported tailpipe assembly cracks. EASA also advises that this issue, if not corrected, could lead to overheating of the structure in the cowling area or separation of parts hence endangering the safety of helicopter flight. \n\tAgusta has issued Bollettino Tecnico No. 139-069, dated August 11, 2006 (BT), which describes procedures for a detailed visual inspection for cracks on the tailpipe. EASA classified this BT as mandatory and issued Emergency AD No. 2006-0242-E, dated August 11, 2006. \n\tThis helicopter model is manufactured in Italy and is type certificated for operation in the United States under the provisions of 14 CFR 21.29 and the applicable bilateral agreement. Pursuant to the applicable bilateral agreement, EASA has kept the FAA informed of the situation described above. The FAA has examined the findings of EASA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States. \n\tSince the unsafe condition described is likely to exist or develop on other Agusta Model AB139 helicopters of the same type design, the FAA issued Emergency AD 2006-17-51 to prevent a fire due to the structure in the cowling area overheating, separation of a part of a tailpipe assembly, and subsequent loss of control of the helicopter. The AD requires the following:\nBefore further flight, and thereafter at intervals not to exceed 25 hours time-in-service, access the rear areas of each tailpipe assembly by removing the rear cowling.\nVisually inspect each tailpipe assembly inside the cowling for a crack.\nInspect the structure surrounding each tailpipe assembly for overheating. If you find areas of overheating, inspect for damage to the surrounding structure.\nInspect for overheating in the area of each tailpipe assembly outside the cowling. Inspect the internal part of each tailpipe assembly in the areas depicted in Areas A, Figure 1, of this AD for a crack: \n\t Clean the end of each tailpipe assembly with a cloth. While applying slight pressure on it, inspect for a crack using a flashlight. \n\t Inspect each tailpipe assembly toward the centerline of the helicopter for a crack using a flashlight. \n\t Inspect each tailpipe assembly toward the outside of the helicopter for a crack using a mirror and a flashlight.\n\tIf you find a crack, before further flight, replace the tailpipe assembly with an airworthy tailpipe assembly. \n\t\tThe short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Inspecting the tail pipe assembly for a crack and for overheating are required before further flight. Also, if you find a crack, replacing the tail pipe assembly with an airworthy tail pipe assembly is required beforefurther flight. Therefore, this AD must be issued immediately. \n\t\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 August 15, 2006, to all known U.S. owners and operators of Agusta Model AB139 helicopters. These conditions still exist, and the AD is hereby published in the Federal Register as an amendment to 14 CFR 39.13 to make it effective to all persons. \n\t\tThe FAA estimates that this AD will affect 16 helicopters of U.S. registry. It will take about 1 work hour to inspect each helicopter and 3 work hours to replace each tail pipe assembly at an average labor rate of $80 per work hour. Required parts will cost about $20,649 per tail pipe assembly. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $366,224, assuming an initial and 24 repetitive inspections on each helicopter and replacing both tailpipe assemblies on half of the fleet (16 tail pipe assemblies). \n\nComments Invited \n\n\n\tThis AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any written data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2006-25703; Directorate Identifier 2006-SW-20-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments. \n\t\tWe will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact withFAA personnel concerning this AD. Using the search function of our docket Web site, you can find and read the comments to any of our dockets, including the name of the individual who sent the comment. You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov . \n\n\n\nRegulatory Findings \n\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\tFor the reasons discussed above, I certify that the regulation: \n\t\t1. Is not a "significant regulatory action" under Executive Order 12866; \n\t\t2. Is not a "significant rule" under the DOT Regulatory Policies and Procedures (44 FR 11034, February 26, \t1979); and \n\t\t3. 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. \n\tWe prepared an economic evaluation of the estimated costs to comply with this AD. See the DMS to examine the economic evaluation. \n\nAuthority for This Rulemaking \n\n\n\t\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\t\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\nList of Subjects in 14 CFR Part 39 \n\n\n\tAir transportation, Aircraft, Aviation safety, Safety. \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\n1. The authority citation for part 39 continues to read as follows: \n\n\n\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n\n\nSec. 39.13 (Amended) \n\n2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: