AD 95-18-07

This amendment supersedes an existing airworthiness directive (AD), applicable to certain Bombardier Model CL-600-1A11, CL-600-2A12, CL-600-2B16, and CL-600-2B19 series airplanes, that currently requires an inspection to detect cracking in the rudder control quadrant; replacement of any cracked quadrant with a new assembly; and retorquing of the castellated nut, as necessary. This amendment requires a follow-on inspection of certain rudder control quadrants to detect cracks that start at the inside root radius of the spigot; modification of any cracked quadrant; and eventual modification of certain quadrants. This amendment also adds airplanes to the applicability of the existing AD. This amendment is prompted by the development of a modification, which, when installed, will positively address the identified unsafe condition. The actions specified by this AD are intended to prevent loss of rudder control due to stress corrosion of the rudder control quadrant.

Final rule

95-18-07 BOMBARDIER, INC. (Formerly Canadair): Amendment 39-9354. Docket 95-NM-18-AD. Supersedes AD 93-22-04, Amendment 39-8729.

Applicability: Model CL-600-1A11 (CL-600) series airplanes, serial numbers 1004 through 1085 inclusive; Model CL-600-2A12 (CL-601) series airplanes, serial numbers 3001 through 3066 inclusive; Model CL-600-2B16 (CL-601-3A and -3R) series airplanes, serial numbers 5001 through 5147 inclusive; and CL-600-2B19 (Regional Jet Series 100) series airplanes, serial numbers 7003 through 7038 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 use the authority provided in paragraph (c) of this AD to request approval from the FAA. This approval may address either no action, if the current configuration eliminates the unsafe condition; or different actions necessary to address the unsafe condition described in this AD. Such a request should include an assessment of the effect of the changed configuration on the unsafe condition addressed by this AD. In no case does the presence of any modification, alteration, or repair remove any airplane from the applicability of this AD.

Compliance: Required as indicated, unless accomplished previously.

To prevent loss of rudder control, accomplish the following:

(a) Within 45 days after the effective date of this AD, perform an ultrasonic inspection to detect cracks at the inside root radius of the spigot of the rudder quadrant, part number (P/N) 600-92614-1 (original quadrant) or P/N 600-92614-3 (quadrant modified with undercut), in accordance with the procedures specified in Canadair Challenger Service Bulletin No. 600-0637, Revision 1, dated November 15, 1994 (for Model CL-600-1A11 series airplanes); Canadair Challenger Service Bulletin No. 601-0426, Revision 1, dated November 15, 1994 (for Model CL-600-2A12 and -2B16 series airplanes); or Canadair Regional Jet Alert Service Bulletin S.B. A601R-27-011, Revision 'A,' dated September 21, 1993, as revised by Notice of Revision A601R-27-011A-1, dated October 6, 1993, and Notice of Revision A601R-27-011A-2, dated June 14, 1994 (for Model CL-600-2B19 series airplanes); as applicable. A fluorescent penetrant inspection may be accomplished in lieu of the ultrasonic inspection provided that the rudder control quadrant assembly is removed prior to inspection. Accomplishment of the modification required by paragraph (b) of this AD eliminates the need for the inspection required by this paragraph, provided that the modification is accomplished within 45 days after the effective date of this AD.

NOTE 2: Rudder quadrants having P/N's 600-92614-1 and -3 are part ofthe rudder quadrants having P/N's 600-92619-1 and -5, respectively.

(1) If any crack is detected, prior to further flight, modify the rudder control quadrant in accordance with Canadair Challenger Service Bulletin No. 600-0637, Revision 1, dated November 15, 1994 (for Model CL-600-1A11 series airplanes); Canadair Challenger Service Bulletin No. 601-0426, Revision 1, dated November 15, 1994 (for Model CL-600-2A12 and -2B16 series airplanes); or Canadair Service Bulletin S.B. 601R-27-015, Revision 'A,' dated October 31, 1994 (for Model CL-600-2B19 series airplanes); as applicable.

(2) If no crack is detected, no further action is required by paragraph (a) of this AD.

(b) Within 6 months after the effective date of this AD, modify the rudder control quadrant, P/N 600-92619-1 or 600-92619-5, in accordance with Canadair Challenger Service Bulletin No. 600-0637, Revision 1, dated November 15, 1994 (for Model CL-600-1A11 series airplanes); Canadair Challenger Service Bulletin No. 601-0426, Revision 1, dated November 15, 1994 (for Model CL-600-2A12 and -2B16 series airplanes); or Canadair Service Bulletin S.B. 601R-27-015, Revision 'A,' dated October 31, 1994 (for Model CL-600-2B19 series airplanes); as applicable. Accomplishment of this modification eliminates the need for the inspection required by paragraph (a) of this AD.

(c) 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 3: Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the New York ACO.

(d) Special flight permits may be issued in accordance withsections 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.

(e) The inspections and modifications shall be done in accordance with Canadair Challenger Service Bulletin No. 600-0637, Revision 1, dated November 15, 1994; Canadair Challenger Service Bulletin No. 601-0426, Revision 1, dated November 15, 1994; Canadair Regional Jet Alert Service Bulletin S.B. A601R-27-011, Revision 'A,' dated September 21, 1993, as revised by Notice of Revision A601R-27-011A-1, dated October 6, 1993, and Notice of Revision A601R-27-011A-2, dated June 14, 1994; or Canadair Service Bulletin S.B. 601R-27-015, Revision 'A,' dated October 31, 1994; as applicable. 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 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, New York Aircraft Certification Office, Engine and Propeller Directorate, 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.

(f) This amendment becomes effective on October 30, 1995.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) by superseding AD 93-22-04, amendment 39-8729 (58 FR 59161, November 8, 1993), which is applicable to certain Bombardier Model CL-600-1A11 (CL-600), CL-600-2A12 (CL-601), CL-600-2B16 (CL-601-3A and -3R), and CL-600-2B19 (Regional Jet Series 100) series airplanes, was published in the Federal Register on May 18, 1995 (60 FR 26700). The action proposed to require a one-time ultrasonic inspection of certain rudder control quadrants to detect cracks that start at the inside root radius of the spigot; modification of any cracked quadrant; and eventual modification of certain quadrants. The action also proposed to expand the applicability of the existing rule to include additional airplanes that have been identified as subject to the addressed unsafe condition.

Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were submitted in response to the proposal or the FAA's determination of the cost to the public.

The FAA has revised paragraphs (a)(1) and (b) of the final rule to correct a service bulletin citation for Model CL-600-2B19 series airplanes. The proposed rule incorrectly specified the service bulletin number for Canadair Service Bulletin S.B. 601R-27-015, Revision 'A,' dated October 31, 1994, as "Canadair Service Bulletin S.B. A601R-27-015." (The preamble to the proposed rule reflected the correct service bulletin citation.)

After careful review of the available data, the FAA has determined that air safety and the public interest require the adoption of the rule with the change previously described. The FAA has determined that this change will neither increase the economic burden on any operator nor increase the scope of the AD.

The FAA estimates that 212 airplanes of U.S. registry will be affected by this AD.

Accomplishment of the inspection will take approximately 4 work hours per airplane, at an average labor rate of $60 per work hour. Based on these figures, the total cost impact of the inspection action on U.S. operators is estimated to be $50,880, or $240 per airplane.

Accomplishment of the modification will take approximately 20 work hours per airplane, at an average labor rate of $60 per work hour. Required parts will be provided by the manufacturer at no cost to operators. Based on these figures, the total cost impact of the modification action on U.S. operators is estimated to be $254,400, or $1,200 per airplane.

Based on the figures discussed above, the total cost impact of this rule on U.S. operators is estimated to be $305,280. This total cost impact figure 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.

The regulations adopted herein will not have substantial direct effectson 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 USC 106(g), 40101, 40113, 44701.

39.13 - [Amended]
2. Section 39.13 is amended by removing amendment 39-8729 (58 FR 59161, November 8, 1993), and by adding a new airworthiness directive (AD), amendment 39-9354, to read as follows: