On December 9, 1999, the FAA issued AD 99-26-13, Amendment 39-11472, Docket No. 99-SW-64-AD, effective January 4, 2000, to require inspecting any tail rotor blade, part number (P/N) 109-0132-02 (all dash numbers), with 400 or more hours TIS for a crack and replacing any cracked blade with an airworthy blade. That action was prompted by three reports of cracked blades and two reports of separation of a tail rotor gearbox. That condition, if not corrected, could result in fatigue failure of a blade, loss of the tail rotor, and subsequent loss of control of the helicopter.
Agusta S.p.A. issued Bollettino Tecnico 109-110, dated July 28, 1999 (technical bulletin), which supersedes Telegraphic Technical Bulletin 109-5, dated January 27, 1987. The technical bulletin specifies dye-penetrant inspecting any blade, P/N 109-0132-02 (all dash numbers), with 400 or more hours TIS, for a crack before further flight and thereafter at intervals not to exceed 100 hours TIS. The technical bulletin also specifies visually inspecting each blade before the first flight of each day and replacing any cracked blade. In the technical bulletin, the manufacturer reemphasizes the importance of performing a detailed inspection of the blade by publishing additional procedures and requirements for personnel conducting the inspections. Agusta S.p.A. is attempting to develop an improved blade, which would provide a basis for terminating the inspection requirement.
Since the issuance of that AD, the FAA has discovered that the requirement in paragraph (b) of AD-99-26-13 mandates replacing a cracked blade with an unairworthy blade. This was an error. The requirement should mandate that any cracked blade be replaced with an airworthy blade.
Since an unsafe condition has been identified that is likely to exist or develop on other Agusta Model A109A and A109A II helicopters of the same type design, this AD supersedes AD 99-26-13, effective January 4, 2000. This AD corrects the mistake in AD 99-26-13 and requires that any cracked blade be replaced with an airworthy blade. This AD also requires dye-penetrant inspecting any blade, P/N 109-0132-02 (all dash numbers), with 400 or more hours TIS, for a crack before further flight and thereafter at intervals not to exceed 100 hours TIS. Also, this AD requires visually inspecting each blade before the first flight of each day. The actions are required to be accomplished in accordance with the technical bulletin described previously. The short compliance time involved is required because the previously described critical unsafe condition can adversely affect the controllability and structural integrity of the helicopter. Therefore, dye-penetrant inspecting each blade for a crack is required before further flight and this AD must be issued immediately.
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for priorpublic comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
The FAA estimates that 54 helicopters will be affected by this AD, that it will take approximately 2.5 work hours to accomplish the inspections, and that 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 $48,600 assuming 6 dye penetrant inspections a year.
Comments Invited
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.
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.
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. 99-SW-91-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.
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."
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
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:
PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. 106(g), 40113, 44701.
39.13 [Amended]
2. Section 39.13 is amended by removing Amendment 39-11472 and by adding a new airworthiness directive (AD), Amendment 39-11493, to read as follows: