AD 94-04-02

This amendment adopts a new airworthiness directive (AD), applicable to certain Canadair Model CL-215-6B11 series airplanes, that requires inspections to detect cracking in the rear engine mount struts, and replacement of struts with new struts, if necessary; and the eventual replacement of all struts with new struts. This amendment is prompted by reports of failures of these rear engine mount struts due to cracking that was caused by rosette welds on the shank of the struts not achieving full weld penetration during manufacture. The actions specified by this AD are intended to prevent failure of the rear engine mount struts, which could subsequently result in reduced structural integrity of the nacelle and engine support structure.

Final rule

94-04-02 CANADAIR: Amendment 39-8820. Docket 93-NM-135-AD.

Applicability: Model CL-215-6B11 series airplanes, serial numbers 1057, 1061, 1080, 1113 through 1115 inclusive, 1121, 1122, 1124, and 1125; turboprop versions only; certificated in any category.

Compliance: Required as indicated, unless accomplished previously.

To prevent failure of the rear engine mount struts, which could subsequently result in reduced structural integrity of the nacelle and engine support structure, accomplish the following:

(a) Within 50 hours time-in-service after the effective date of this AD, perform a visual inspection to detect cracking in the rear engine mount struts, part number (P/N) 87110016- 003, in accordance with Canadair Alert Service Bulletin 215-A3040, dated September 2, 1992.

(1) If no cracking is detected, repeat the visual inspection thereafter at intervals not to exceed 50 hours time-in-service, until the requirements of paragraph (b) of this AD are accomplished.

(2) If any cracking is detected, prior to further flight, replace the engine rear mount strut with a new strut, P/N 87110016-009 or -011, in accordance with the service bulletin.

(b) Within 2 years after the effective date of this AD, replace all engine rear mount struts, with new struts, P/N 87110016-009 or -011, in accordance with Canadair Alert Service Bulletin 215-A3040, dated September 2, 1992. Such replacement constitutes terminating action for the inspections required by this AD.

(c) As of the effective date of this AD, no person shall install a rear engine mount strut, P/N 87110016-003, on any airplane.

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

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

(f) The inspections and replacement shall be done in accordance with Canadair Alert Service Bulletin 215-A3040, dated September 2, 1992. 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 A, Montreal, 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, 181 South Franklin Avenue, Room 202, Valley Stream, New York; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

(g) This amendment becomes effective on April 4, 1994.

A proposal to amend part 39 of the Federal Aviation Regulations to include an airworthiness directive (AD) that is applicable to certain Canadair Model CL-215-6B11 series airplanes was published in the Federal Register on October 13, 1993 (58 FR 52931). That action proposed to require repetitive visual inspections to detect cracking in the rear engine mount struts, and replacement of struts with new struts, if necessary. That action also proposed to require the eventual replacement of all struts with new struts; such replacement would constitute terminating action for the visual inspections.

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 determined that air safety and the public interest require the adoption of the rule as proposed.

Currently, there are no Canadair Model CL-215-6B11 series airplanes on the U.S. Register. However, should an affected airplane be imported and placed on the U.S. Register in the future, it would take approximately 10 work hours per airplane to accomplish the required actions, and that the average labor rate is $55 per work hour. Required parts will be provided by the manufacturer at no cost to the operators. Based on these figures, the total cost impact of the AD will be $550 per airplane.

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 14 CFR part 39 of the Federal Aviation Regulations as follows:

PART 39 - AIRWORTHINESS DIRECTIVES
1. The authority citation for part 39 continues to read as follows:
Authority: 49 U.S.C. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89.

39.13 - [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: