On April 15, 2003, the FAA issued Emergency AD 2003-08-51 for the specified model helicopters, which requires, before further flight, reducing the retirement life of certain tail rotor blades from 5,140, 5,200, or 10,000 hours time-in-service (TIS) to 400 hours TIS, performing a one-time visual inspection of each pitch horn for a crack or corrosion, and replacing unairworthy tail rotor blades with airworthy tail rotor blades. The Emergency AD also requires revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life, and reporting information to the FAA within 24 hours following the one-time inspection. That action was prompted by two reports of cracked pitch horns that failed during flight. In both occurrences, the pilot was able to land the helicopter without further incident. Investigation revealed that the cause of the failures was a fatigue crack in the pitch horns that developed before the tail rotor blade reached its retirement life. This condition, if not corrected, could result in a pitch horn separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter. \n\n\tSince the unsafe condition described is likely to exist or develop on other MD Helicopters, Inc. Model 369A, D, E, H, HE, HM, HS, F, and FF helicopters of the same type designs, the FAA issued Emergency AD 2003-08-51 to prevent a pitch horn from separating from the tail rotor blade, leading to an unbalanced condition, vibration, loss of tail rotor pitch control, and loss of directional control of the helicopter. The AD requires, before further flight, reducing the retirement life of certain tail rotor blades from 5,140, 5,200, or 10,000 hours TIS to 400 hours TIS, performing a one-time visual inspection of each pitch horn for a crack or corrosion, and replacing unairworthy tail rotor blades with airworthy tail rotor blades. The AD also requires revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life, and reporting information to the FAA within 24 hours following the one-time inspection. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the structural integrity of the helicopter. Therefore, reducing the retirement life of certain tail rotor blades; performing a one-time visual inspection of each pitch horn; replacing unairworthy tail rotor blades; and revising the Airworthiness Limitations section of the helicopter maintenance manual to reflect the reduced retirement life are required before further flight, and this AD must be issued immediately. \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 existedto make the AD effective immediately by individual letters issued on April 15, 2003, to all known U.S. owners and operators of MD Helicopters, Inc. Model 369A, D, E, H, HE, HM, HS, F, and FF 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\n\tThe Emergency AD contained two typographical errors that are corrected in this AD. Paragraph (c) of the Emergency AD stated "400 hours TIS" twice, and the "or" in the listing of part numbers should have been "and". \n\n\tOn July 10, 2002, the FAA issued a new version of 14 CFR part 39 (67 FR 47997, July 22, 2002), which governs the FAA's AD system. The regulation now includes material that relates to altered products, special flight permits, and alternative methods of compliance. Because we have now included this material in part 39, we no longer need to include it in each individual AD. \n\n\tThe FAA estimates that this AD will affect 213 helicopters of U.S. registry, and replacing the tail rotor blades will take approximately 2 work hours per helicopter to accomplish at an average labor rate of $60 per work hour. Required parts will cost approximately $2,000 per helicopter. Based on these figures, we estimate the total cost impact of the AD on U.S. operators to be $2,120 per helicopter, or $451,560 to replace all the blades in the fleet. \n\nComments Invited \n\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 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 mailed 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. 2003-SW-17-AD." The postcard will be date stamped and returned to the commenter.The regulations adopted herein 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. Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132. \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 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\n\tAir transportation, Aircraft, Aviation safety, Safety. \n\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\tAuthority: 49 U.S.C. 106(g), 40113, 44701. \n\n§ 39.13 (Amended) \n\n2. Section 39.13 is amended by adding a new airworthiness directive to read as follows: