On January 6, 1999, the FAA issued Priority Letter AD 99-02-01, applicable to BHTC Model 206L, 206L-1, 206L-3, and 206L-4 helicopters, to require visual inspections and visual checks at specified time intervals, and a FPI for any cracks in the tailboom skins around the horizontal stabilizer openings. Inserting a copy of the priority letter AD into the RFM is also required. That action was prompted by 7 reports of fatigue cracks that propagated from the edges of the horizontal stabilizer openings in the tailboom skins. That condition, if not corrected, could result in separation of the tailboom and subsequent loss of control of the helicopter.\n \n Since the issuance of that priority letter AD, further review of crack growth rates has shown that cracks need to be detected before they propagate from underneath the horizontal stabilizer supports. Therefore, this superseding AD requires, at specified time intervals, not just visually inspecting and checking the tailboom skins in the area of the horizontal stabilizer supports, but also removing the horizontal stabilizer supports and visually inspecting the edges of the tailboom skins around the horizontal stabilizer openings for cracks. Removing the horizontal stabilizer supports will allow the detection of cracks at an earlier stage.\n \n Transport Canada, which is the airworthiness authority for Canada, has notified the FAA that an unsafe condition may exist on BHTC Model 206L, 206L-1, 206L-3, and 206L-4 helicopters. Transport Canada advises that cracks were found on the tailboom skins in the area of the horizontal stabilizer.\n\n Bell Helicopter Textron has issued BHTC Alert Service Bulletin No. 206L-98-114, dated November 25, 1998, which specifies a pilot preflight check for cracks in the horizontal stabilizer area before the first flight of each day. Transport Canada classified this service bulletin as mandatory and issued AD No. CF-98-42R1, dated February 16, 1999,which states that a review of crack growth rates indicates the need to detect cracks earlier. In addition to the preflight check for cracks introduced by the service bulletin, the Transport Canada AD requires removing the horizontal stabilizer supports and visually inspecting the tailboom skin underneath the horizontal stabilizer supports at specified time intervals.\n\n These helicopter models are manufactured in Canada and are type certificated for operation in the United States under the provisions 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, Transport Canada has kept the FAA informed of the situation described above. The FAA has examined the findings of Transport Canada, reviewed all available information, and determined that AD action is necessary for products of these type designs that are certificated for operation in the United States.Since an unsafe condition has been identified that is likely to exist or develop on other BHTC Model 206L, 206L-1, 206L-3, and 206L-4 helicopters of the same type designs, this AD supersedes Priority Letter AD 99-02-01 to require: \n\nPrior to further flight, and thereafter, at intervals not to exceed 10 hours time-in-service (TIS) until a one-time FPI is accomplished, a visual inspection for any crack in the tailboom skins around the horizontal stabilizer supports; \n \nAt intervals not to exceed 5 hours TIS, a visual preflight pilot check for any crack in the tailboom skins around the horizontal stabilizer supports; \n\nWithin 50 hours TIS, a one-time FPI for any crack in the edge of the tailboom skins around the left and right horizontal stabilizer openings on the tailboom ; and\n\nAfter completion of the one-time FPI, at intervals not to exceed 100 hours TIS, a visual inspection of the entire edge of the horizontal stabilizer opening on both sides of the tailboom for any crack.\n\n The visual check that is required at intervals not to exceed 5 hours TIS may be performed by an owner/operator (pilot), and must be entered into the aircraft records showing compliance with paragraph (b) of this AD in accordance with sections 43.11 and 91.417 (a)(2)(v) of the Federal Aviation Regulations (14 CFR sections 43.11 and 91.417 (a)(2)(v)). This AD allows a pilot to perform this check because it involves only a visual check for cracking in the tailboom skins, and can be performed equally well by a pilot or mechanic. These checks are additional measures to ensure that a crack that is visible without the aid of a magnifying glass has not developed during the time between maintenance inspections.\n\n The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter, and this AD must be issued immediately. Therefore, a visual inspection to detect any crack using a 10-power or higher magnifying glass is required before further flight and at intervals not to exceed 10 hours TIS until accomplishing the FPI; a visual preflight pilot check for any crack is required at intervals not to exceed 5 hours TIS; a one-time FPI is required within 50 hours TIS; and after completion of the one-time FPI and at intervals not to exceed 100 hours TIS, a visual inspection for cracks around the left and right horizontal stabilizer opening on both sides of the tailboom using a 10-power or higher magnifying glass is required.\n\n Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.\n\n The FAA estimates that 1,546 helicopters of U.S. registry will be affected by this AD, that it will take approximately 2 work hours per helicopter to conduct aFPI; 0.5 work hour to conduct a visual inspection; 0.5 work hour to conduct the repetitive visual check; and 20 work hours to replace the tailboom, if necessary. The average labor rate is $60 per work hour. Required parts will cost approximately $22,000 per tailboom. Based on these figures, the total cost impact of the AD on U.S. operators is estimated to be $278,280 to conduct the initial fluorescent-penetrant inspections and to conduct one of the inspections and one of the visual checks for the entire fleet; $36,145,480 if it is necessary to replace the tailboom on the entire fleet.\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 theircomments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket No. 99-SW-23-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 newairworthiness directive (AD), Amendment 39-11207, to read as follows: