Discussion
We issued a notice of proposed rulemaking (NPRM) to amend 14 CFR part 39 to include an AD that would apply to the specified products. That NPRM was published in the Federal Register on April 30, 2009 (74 FR 19902). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:
A change in dimensions of the fuse blocks in the Auxiliary Power Unit (APU) Start Contactor Assembly (ASCA) box assembly can cause an incorrect interface between the bus bars and fuses. This condition can result in an increase in temperature, which could damage the ASCA box and/or compromise the availability of battery bus supply.
The unsafe condition could result in the ignition of a fire in the ASCA box. The required actions include inspecting the ASCA boxes to determine the part number; and for certain ASCA boxes, doing a detailed inspection of the fuse block date code, and replacing the fuse block with new hardware if necessary. You may obtain further information by examining the MCAI in the AD docket.
Comments
We gave the public the opportunity to participate in developing this AD. We considered the comment received.
Request To Change Compliance Time for Replacement
American Eagle Airlines (AEA) requests that the compliance time in paragraph (f)(1) of the NPRM for replacing the fuse blocks be changed from "before further flight'' to within 1,500 flight hours after the effective date of this AD. AEA explains that the new compliance time will give operators the benefit of knowing how much down-time will be needed to replace the fuse blocks, while keeping to the restrictions of 1,500 flight hours required for inspecting the ASCA box.
We disagree with the request. While we recognize that changing the compliance time for replacing the fuse blocks from "before further flight'' to within 1,500 flight hours after the effective date of this AD benefits the operators in their planning, wefind that, to achieve an adequate level of safety for the affected airplanes, fuse blocks known to be un-airworthy must be replaced before further flight. We have made no change to this AD in this regard.
Request To Allow a Records Check in Lieu of Inspection To Determine Part Number
AEA requests that a records check be allowed, if sufficient records exist, to comply with the inspection of the ASCA box to determine the part numbers. AEA explains that the records check would potentially prevent unnecessary inspections.
We agree. We have determined that a review of the airplane maintenance records is acceptable in lieu of the inspection to determine the part number of the ASCA boxes if the part number of the ASCA boxes can be conclusively determined from that review. We have revised paragraph (f)(1) of this AD accordingly.
Conclusion
We reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD with the change described previously. We determined that this change will not increase the economic burden on any operator or increase the scope of the AD.
Differences Between This AD and the MCAI or Service Information
We have reviewed the MCAI and related service information and, in general, agree with their substance. But we might have found it necessary to use different words from those in the MCAI to ensure the AD is clear for U.S. operators and is enforceable. In making these changes, we do not intend to differ substantively from the information provided in the MCAI and related service information.
We might also have required different actions in this AD from those in the MCAI in order to follow our FAA policies. Any such differences are highlighted in a NOTE within the AD.
Costs of Compliance
We estimate that this AD affects 108 products of U.S. registry. We also estimate that it takes about 5 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Based on these figures, we estimate the cost of this AD to U.S. operators to be $43,200, or $400 per product.
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 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 this AD:
1. Is not a "significant regulatory action'' under Executive Order 12866;
2. Is not a "significant rule'' under the 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 and placed it in the AD docket.
Examining the AD Docket
You may examine the ADdocket on the Internet at http:// www.regulations.gov; or in person at the Docket Operations office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The AD docket contains the NPRM, the regulatory evaluation, any comments received, and other information. The street address for the Docket Operations office (telephone (800) 647-5527) is in the ADDRESSES section. Comments will be available in the AD docket shortly after receipt.
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 AD: