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 June 9, 2008 (73 FR 32493). That NPRM proposed to correct an unsafe condition for the specified products. The MCAI states:
During a pre-delivery flight of a CL-600-2C10 aircraft, the AC essential bus did not come on-line following deployment of the Air Driven Generator (ADG). Following investigation, it was determined that a specific batch of contactors in the ADG Power Center (ADGPC) is susceptible to failure due to low contact pressure. This directive mandates inspection of the ADGPC and replacement of any contactors in the suspect batch. It also prohibits future installation of ADGPCs and contactors that have not been inspected per this directive.
The unsafe condition is a malfunction of the emergency AC generation and control system that supplies emergency AC power to essential flight instruments, including the flap and slat system, pitch trim system, and hydraulic pump 3B. Loss of essential flight instruments could prevent continued safe flight and landing of the airplane. You may obtain further information by examining the MCAI in the AD docket.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received from a single commenter.
Request To Reduce Compliance Time
The Air Line Pilots Association (ALPA) supports the intent of the NPRM, but recommends that the compliance time allowed for the proposed actions be shortened from 24 months to 3 months. ALPA states that although its review of available fleet data did not reveal any incidents of full electrical failures in Bombardier airplanes, the ADG is the only remaining source of electrical power sustaining the batteries and flight-critical electrical systems if all other generators fail or are unavailable. ALPA adds that, under certain circumstances, there are procedures for deferring activation of an engine-driven or auxiliary power unit (APU) generator; however, the ADG is a non-deferrable item. ALPA notes that, given the potential consequences of a full electrical system failure, particularly in the low visibility weather conditions in which these airplanes routinely operate, the compliance time should be reduced.
We do not agree to reduce the compliance time specified in paragraph (f)(1) of this AD. In developing the compliance time for this AD action, we considered not only the safety implications of the identified unsafe condition, but the average utilization rate of the affected fleet, the practical aspects of an orderly inspection of the fleet during regular maintenance periods, and the availability of replacement parts. In addition, we also considered the manufacturer's recommendation for an appropriate compliance time. After considering all the available information, we determined that performing the actions within 5,000 flight hours or 24 months, whichever occurs first, represents an appropriate interval of time in which the required actions can be performed in a timely manner within the affected fleet, while still maintaining an adequate level of safety. We have made no change to the AD in this regard.
Request To Limit Special Flight Permit
ALPA also recommends that no flights be allowed with a non- operating engine-driven or APU generator unless the AD has been complied with.
We do not agree to limit flights as ALPA recommends. In the event of failure of an ADG and one engine driven generator (EDG), the airplane can be powered by one EDG and the APU generator. If both the ADG and APU generator fail, the airplane AC buses can be powered by both EDGs. Based on these factors, we have determined that such a limitation is not necessary. We have not changed the AD in this regard.
ConclusionWe reviewed the available data, including the comments received, and determined that air safety and the public interest require adopting the AD as proposed.
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 will affect 306 products of U.S. registry. We also estimate that it will take about 9 work-hours per product to comply with the basic requirements of this AD. The average labor rate is $80 per work-hour. Required parts will cost about $0 per product. Where the service information lists required parts costs that are covered under warranty, we have assumed that there will be no charge for these parts. As we do not control warranty coverage for affected parties, some parties may incur costs higher than estimated here. Based on these figures, we estimate the cost of this AD to the U.S. operators to be $220,320, or $720 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 FAAwith 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 AD docket 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: