AD 97-18-10

This amendment adopts a new airworthiness directive (AD), applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes that requires a one-time inspection of the direct current (DC) power distribution system for reliability, and correction or repair, of any fuse holders and associated electrical wiring, if necessary. This amendment is prompted by a report indicating that a loose fuse holder caused the DC power distribution system to short circuit on one of the affected airplanes, which resulted in a burnt wire between circuit breaker panel CBP-2 and junction box JB7. The actions specified by this AD are intended to prevent such short circuiting, which could result in a burnt wire, smoke entering the cockpit area, and consequent passenger injury due to smoke inhalation.

Final rule

97-18-10 BOMBARDIER, INC. (Formerly Canadair): Amendment 39-10120. Docket 96-NM-271-AD.
Applicability: Model CL-600-2B19 (Regional Jet Series 100) airplanes, serial numbers 7003 through 7105 inclusive; certificated in any category.

NOTE 1: This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (b) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To prevent the direct current (DC) power distribution system from short circuiting, which could result in a burnt wire, smoke entering the cockpit area, and consequent passenger injury due to smoke inhalation, accomplish the following:

(a) Within 600 hours time-in-service after the effective date of this AD, perform a one-time inspection of the DC power distribution system for reliability in accordance with Canadair Regional Jet Alert Service Bulletin S.B. A601R-24-056, Revision A, dated July 9, 1996. Prior to further flight, correct or repair any discrepant fuse holders and associated electrical wiring, in accordance with the service bulletin.

(b) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, New York Aircraft Certification Office (ACO), FAA, Engine and Propeller Directorate. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, New York ACO.

NOTE 2: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(c) Special flight permits may be issued in accordance with sections 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

(d) The inspection shall be done in accordance with Canadair Regional Jet Alert Service Bulletin S.B. A601R-24-056, Revision A, dated July 9, 1996. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Bombardier, Inc., Canadair Aerospace Group, P.O. Box 6087, Station Centre-ville, Quebec H3C 3G9, Canada. Copies may be inspected at the FAA,Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the FAA, Engine and Propeller Directorate, New York Aircraft Certification Office, 10 Fifth Street, Third Floor, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(e) This amendment becomes effective on October 14, 1997.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to certain Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes was published in the Federal Register on June 4, 1997 (62 FR 30481). That action proposed to require a one-time inspection of the direct current (DC) power distribution system for reliability, and correction or repair, of any fuse holders and associated electrical wiring, if necessary.

No comments were submitted in response to the proposal or the FAA s determination of the cost to the public.

Conclusion
The FAA has determined that air safety and the public interest require the adoption of this rule as proposed.

Cost Impact
The FAA estimates that 41 Bombardier Model CL-600-2B19 (Regional Jet Series 100) airplanes of U.S. registry will be affected by this AD, that it will take approximately 14 work hours per airplane to accomplish the required actions, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the AD on U.S. operators is estimated to be $34,440, or $840 per airplane.

The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted.

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.

For the reasons discussed above, I certify that this action (1) is not a "significant regulatory action" under Executive Order 12866; (2) is not a "significant rule" under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 the Amendment
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: