Discussion
Transport Canada Civil Aviation (TCCA), which is the airworthiness authority for Canada, notified us that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. TCCA advises that there have been eight incidents of short circuit failures of Tyco Hartman alternating current (AC) contactors 1K4XD and K4XA, located in the avionics bay on Model CL-600-2B19 (Regional Jet Series 100 & 440) airplanes. All of the failed AC contactors had a terminal base plate made from Ultem 2200 material. In several cases, arcing, which initiated due to the presence of contaminants between the power studs, resulted in a fire, which continued until power to the AC contactor was interrupted, either by the wire being burned through or by the generator falling off-line. Short circuit failures of AC contactors, if not prevented, could result in arcing, which could result in smoke or fire.
Relevant Service Information
Bombardier has issued Service Bulletin 601R-24-122, Revision A, dated July 13, 2006. The service bulletin describes procedures for inspecting contactors 1K4XD, 2K4XD, and K4XA to determine which contactors have an Ultem 2200 terminal base plate (the plate is made from a black molded thermal plastic material), and applying RTV 732 sealant or RTV 3145 sealant, if necessary. TCCA mandated the service bulletin and issued Canadian airworthiness directive CF-2006-17, dated July 11, 2006, to ensure the continued airworthiness of these airplanes in Canada.
FAA's Determination and Requirements of this AD
This airplane model is manufactured in Canada and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) and the applicable bilateral airworthiness agreement. As described in this bilateral airworthiness agreement, TCCA has kept the FAA informed of the situation described above. Wehave examined TCCA's findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.
Therefore, we are issuing this AD to prevent short circuit failures of certain AC contactors, which could result in arcing and consequent smoke or fire. This AD requires accomplishing the actions specified in the service information described previously, except as discussed under "Difference Among the AD, Service Bulletin, and Canadian Airworthiness Directive."
Difference Among the AD, Service Bulletin, and Canadian Airworthiness Directive
The service bulletin specifies to determine if the terminal base plate is made of a black molded thermal plastic material. The Canadian airworthiness directive specifies doing a visual inspection of the contactors to determine which contactors have an Ultem 2200 terminal base plate. However, operators should note that we have determined that the inspection should be described as a "general visual inspection" to determine which contactors have an Ultem 2200 terminal base plate (i.e., a plate made from a black molded thermal plastic material). Note 1 has been included in this AD to define this type of inspection.
Interim Action
We consider this AD interim action. If final action is later identified, we may consider further rulemaking then.
FAA's Determination of the Effective Date
An unsafe condition exists that requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days. The compliance time for doing the required actions is within 800 flight hours or four months. Based on the large number of affected U.S. registered airplanes (739) and the amount of time required to accomplish the required actions, including corrective actions (27 hours), we consider that this compliance time is necessary to avoid unnecessarily disrupting flight schedules.
Comments Invited
This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2006- 25536; Directorate Identifier 2006-NM-158-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.
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 ofpower and responsibilities among the various levels of government.
For the reasons discussed above, I certify that the 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); 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. 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 Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):