Discussion
Transport Canada Civil Aviation (TCCA), which is the aviation authority for Canada, has issued Canadian Airworthiness Directive CF- 2011-46, dated December 20, 2011 (referred to after this as ``the MCAI''), to correct an unsafe condition for the specified products. The MCAI states:
There have been several reports of the loss of certain Alternating Current (AC) systems along with the tripping of associated circuit breakers. During maintenance troubleshooting, the same AC power wire bundle was found burnt. All AC systems and AC Generators could be affected by damage to this AC power wire bundle resulting in the loss of ice protection systems for the angle of attack vanes, pitot probes, engine inlets or windshields. In icing conditions, the loss of the ice protection systems could affect continued safe flight.
This [TCCA] Airworthiness Directive (AD) mandates the detailed inspection [for damage] of the AC power wire bundle [and repair if necessary] and segregation of the wires within the affected AC power wire bundle to prevent a dual system loss [and installing Teflon tubing].
The detailed inspection for damage includes inspecting for any foreign object damage (FOD), damage due to sharp bends and kinking or deterioration, insulation cracking, evidence of heat damage to the insulation, and chafing. The unsafe condition is the loss of ice protection systems for the angle of attack vanes, pitot probes, engine inlets, and windshields, and consequent loss of or misleading airspeed indication and increased workload for the flight crew, which could lead to loss of control of the airplane. You may obtain further information by examining the MCAI in the AD docket.
Relevant Service Information
Bombardier has issued Service Bulletin 84-24-52, dated November 22, 2011. The actions described in this service information are intended to correct the unsafe condition identified in the MCAI.
Differences Between the AD and the MCAI
Although the MCAI recommends accomplishing the actions within 600 flight hours or 90 days, whichever occurs first, after the effective date of the MCAI, this AD requires accomplishment within 400 flight hours or 60 days, whichever occurs first, after the effective date of this AD. We find that a compliance time of 600 flight hours or 90 days, whichever occurs first, would not address the unsafe condition soon enough to maintain an adequate level of safety for the affected fleet. In developing an appropriate compliance time for this AD, we considered the degree of urgency associated with addressing the unsafe condition, the upcoming inclement weather conditions, and the maximum interval of time allowable for all affected airplanes to continue to operate without compromising safety. We find that 400 flight hours or 60 days, whichever occurs first, after the effective date of this AD, to be an appropriate compliance time to complete these actions. This difference has been coordinated with TCCA.
FAA's Determination and Requirements of This AD
This product has been approved by the aviation authority of another country, and is approved for operation in the United States. Pursuant to our bilateral agreement with the State of Design Authority, we have been notified of the unsafe condition described in the MCAI and service information referenced above. We are issuing this AD because we evaluated all pertinent information and determined the unsafe condition exists and is likely to exist or develop on other products of the same type design.
FAA's Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of this AD. The FAA has found that the risk to the flying public justifies waiving notice and comment prior to adoption of this rule because there have been several reports of the loss of certain AC systems along with the tripping of associated circuit breakers. During maintenance troubleshooting, the same AC power wire bundle was found burnt. All AC systems and AC Generators could be affected by damage to this AC power wire bundle resulting in the loss of ice protection systems for the angle of attack vanes, pitot probes, engine inlets or windshields. In icing conditions, the loss of the ice protection systems could affect continued safe flight. Therefore, we determined that notice and opportunity for public comment before issuing this AD are impracticable and that good cause exists for making this amendment effective in fewer than 30 days.
Comments Invited
This AD is a final rule that involves requirements affecting flight safety, and we did not precede it by notice and opportunity for public comment. We invite you to send any written relevant data, views, or arguments about this AD. Send your comments to an address listed under the ADDRESSES section. Include ``Docket No. FAA-2012-0037; Directorate Identifier 2012-NM-003-AD'' at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of this AD. We will consider all comments received by the closing date and may amend this AD because of those comments.
We will post all comments we receive, without change, to http://www.regulations.gov, including any personal information you provide. We will also post a report summarizing each substantive verbal contact we receive about this AD.
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
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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 proposed regulation:
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);
3. Will not affect intrastate aviation in Alaska; and
4. 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.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.