The FAA proposed to amend 14 CFR part 39 with a proposed airworthiness directive (AD). The proposed AD applies to Turbomeca Arriel 1B, 1D, and 1D1 turboshaft engines. We published the proposed AD in the Federal Register on November 4, 2005 (70 FR 67099). That action proposed to require inspecting the NGV2 for wall thickness.
Examining the AD Docket
You may examine the docket that contains the AD, any comments received, and any final disposition in person at the Docket Management Facility Docket Office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Office (telephone (800) 647-5227) is located on the plaza level of the Department of Transportation Nassif Building at the street address stated in ADDRESSES. Comments will be available in the AD docket shortly after the DMS receives them.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comment received.
Request To Include an End Date
One commenter requests that we include an end date in the AD, of December 31, 2006. This end date would help manage the risk of failure, while causing the least amount of disruption in the form of helicopter grounding.
We agree. We changed compliance paragraph (e) to read "You are responsible for having the actions required by this AD performed at the next shop visit or the next accessibility of the NGV2 after the effective date of this AD, whichever occurs first, but no later than December 31, 2006, unless the actions have already been done.''
Clarification of Unsafe Condition
For clarification that the AD is applicable to only single-engine installations, we changed the unsafe condition in the AD to read "We are issuing this AD to detect and prevent perforation of the 2nd stage nozzle guide vanes (NGV2) that could cause fracture of a turbine blade that could result in an uncommanded engine in-flight shutdown on a single-engine helicopter.''
Conclusion
We have carefully reviewed the available data, including the comment received, and determined that air safety and the public interest require adopting the AD with the changes described previously. We have determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Costs of Compliance
We estimate that this AD will affect 571 engines installed on helicopters of U.S. registry. We also estimate that it will take about 0.5 work hours per engine to perform the actions, and that the average labor rate is $65 per work hour. No parts are required. Based on these figures, we estimate the total cost of the AD to U.S. operators to be $18,558.
Authority for This Rulemaking
Title 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.
We 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.
Regulatory Findings
We 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.
For the reasons discussed above, I certify that this AD:
(1) Is not a "significant regulatory action'' under Executive Order 12866;
(2) Is not a "significant rule'' under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979); and
(3) 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.
We prepared a summary of the costs to comply with this AD and placed it in the AD Docket. You may get a copy of this summary at the address listed under ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the Amendment
Accordingly, under the authority delegated to me by the Administrator, the Federal Aviation Administration amends 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.
Sec. 39.13 [Amended]
2. The FAA amends Sec. 39.13 by adding the following new airworthiness directive: