The FAA proposed to amend 14 CFR part 39 with an AD for Airbus Model A320 series airplanes. That action, published in the Federal Register on March 8, 2005 (70 FR 11170), proposed to require post-maintenance bleeding of accumulated air from, or ground functional testing of, the ram air turbine (RAT) system; modifying and reidentifying the airborne ground check module of the RAT system; and replacing the RAT reducer assembly if applicable.
Comments
We provided the public the opportunity to participate in the development of this AD. We have considered the comments that have been submitted on the proposed AD.
Support for the Proposed AD
One commenter supports the proposed AD.
Request To Revise Applicability
One commenter requests that we change a part number that was incorrectly referenced in the applicability of the proposed AD. The commenter states that part number (P/N) 760106 is incorrect and that it should be changed to P/N 769106.
We agree with this request. P/N 760106 is a part number that is not referenced by the Airbus service bulletin; it appeared due to a typographical error. We have corrected paragraph (c) of the final rule to read P/N 769106, as specified in the Airbus service bulletin and the French airworthiness directive.
Request To Revise Requirement for Bleeding of Blue Hydraulic Circuit
The same commenter requests that we revise the wording of paragraphs (f) and (g) of the proposed AD. The commenter asserts that the statement "after performing any maintenance on the blue hydraulic circuit" that appears in paragraphs (f) and (g) is too vague and can be taken as requiring unnecessary bleeding of the blue hydraulic circuit. The commenter suggests that we revise this wording to read "after performing any maintenance that would normally require bleeding of the blue hydraulic circuit (as instructed by the related AMM procedure)." The commenter states that such wording would eliminate any unneeded maintenance introduced by the proposed AD and still ensure that, during any in-flight emergency, a RAT system failure does not occur.
We agree with this request. We always seek to use unambiguous language and the specified statement could be taken as requiring unnecessary bleeding of the blue hydraulic circuit. Therefore, to ensure that bleeding of the blue hydraulic circuit must be performed only as a necessary part of a maintenance action, we have revised paragraphs (f) and (g) of the final rule to reflect the commenter's wording.
Explanation of Change to Applicability
The FAA has revised the applicability of the proposed AD to identify model designations as published in the most recent type certificate data sheet for the affected models.
Conclusion
We have carefully reviewed the available data, including the comments that have been submitted, 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
This AD will affect about 130 airplanes of U.S. registry.
The system bleed/functional test will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Based on these figures, the estimated cost of the required actions for U.S. operators is $8,450, or $65 per airplane.
The airborne ground check module (AGCM) replacement will take about 2 work hours per airplane, at an average labor rate of $65 per work hour. Required parts will be supplied at no charge. Based on these figures, the estimated cost of this action for U.S. operators is $16,900, or $130 per airplane.
The reducer replacement, for subject airplanes, will take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Required parts will be supplied at no charge. Based on these figures, the estimated cost of this action for U.S. operators is $65 per airplane.
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 havefederalism 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 regulatory evaluation of the estimated costs to comply with this AD. See the ADDRESSES section for a location to examine the regulatory evaluation.
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 FAA 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 (AD):