Transport Canada Aviation (TCA), which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain Bombardier Model CL-600-2B19 (Regional Jet Series 100 and 200) series airplanes. TCA advises that two cases of chafing on the electrical wiring conduits of the right wing crossflow valve in the center fuel tank have been reported. Findings indicate that chafing of those electrical wiring conduits may be caused by inadequate clearance between the tube assemblies and adjacent structures. These conditions, if not corrected, could result in electrical arcing and consequent fire or explosion in the center fuel tank.
Explanation of Relevant Service Information
Bombardier has issued Alert Service Bulletin SB A601R-28-036, Revision A, dated September 4, 1998, which describes procedures for a one-time inspection to detect chafing or cracking of all electrical wiring conduits in the center fuel tank, andinadequate clearance between the tube assemblies and adjacent structures. The alert service bulletin also describes procedures for corrective actions, which include repairing or replacing any damaged conduit that is outside specified limits with a tube assembly (as specified in the service bulletin), and relocating and reforming the conduits to provide adequate clearance. In addition, the alert service bulletin specifies procedures for a modification to reinforce the crossflow shutoff valve conduit with a bracket to ensure the continued safety of the electrical conduit installation in the center fuel tank. Accomplishment of the actions specified in the alert service bulletin is intended to adequately address the identified unsafe condition. TCA classified this alert service bulletin as mandatory and issued airworthiness directive CF-98-35, dated September 15, 1998, in order to assure the continued airworthiness of these airplanes in Canada.
FAA's Conclusions
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. Pursuant to this bilateral airworthiness agreement, TCA has kept the FAA informed of the situation described above. The FAA has examined the findings of TCA, reviewed all available information, and determined that AD action is necessary for products of this type design that are certificated for operation in the United States.
Explanation of Requirements of Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, this AD is being issued to prevent electrical arcing and consequent fire or explosion in the center fuel tank. This AD requires a one-time visual inspection to detect chafing or cracking of all electrical wiring conduits located in thecenter fuel tank, and inadequate clearance between the tube assemblies and adjacent structures; and corrective actions, if necessary. This AD also requires a modification to reinforce the right wing crossflow shutoff valve conduit by installing a bracket support kit. The actions are required to be accomplished in accordance with the alert service bulletin described previously, except as discussed below.
Differences Between This AD and the Relevant Service Information
Operators should note that, although the effectivity of the alert service bulletin specifies serial numbers 7003 through 7067 inclusive, and 7069 through 7246 inclusive, the applicability of this AD specifies serial numbers 7003 through 7246 inclusive. (The Canadian airworthiness directive specifies the same serial numbers as shown in the Applicability of this AD.)
Operators also should note that, although Part A of the Accomplishment Instructions of the alert service bulletin specifies that the operator may accomplish inspections in accordance with either Option 1 or Option 2, paragraph (a) of this AD requires the accomplishment of Option 1. Option 1 specifies that corrective action is required if any sign of damage or inadequate clearance is found, whereas Option 2 specifies corrective action only if fuel leakage is found. The FAA has determined that, in cases where certain known unsafe conditions exist, and where actions to detect and correct that unsafe condition can be readily accomplished, those actions must be required. The FAA considers that Option 2 would not provide an adequate level of safety for the affected fleet. [The Canadian airworthiness directive also specifies Part A (Option 1) of the alert service bulletin.]
Determination of Rule's Effective Date
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this rule by submitting such written data, views, or arguments as they may desire. Communications shall identify the Rules Docket number and be submitted in triplicate to the address specified under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the rule. All comments submitted will be available, both before and after the closing date for comments, in the Rules Docket for examination by interested persons. A report that summarizes each FAA-public contact concerned with the substance of this AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 98-NM-330-AD." The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein will not have substantial direct effects 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. Therefore, in accordance with Executive Order 12612, it is determined that this final rule does not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise would be significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, may be obtained from the Rules Docket at the location provided under the caption "ADDRESSES."
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of theAmendment
Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration amends part 39 of the Federal Aviation Regulations (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.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: