Transport Canada Aviation, which is the airworthiness authority for Canada, recently notified the FAA that an unsafe condition may exist on certain Canadair Model CL-600-2B19 (Regional Jet) series airplanes. Transport Canada Aviation advises that there have been four reports of failures of the integrated drive generator (IDG) constant speed drive (CSD) on Canadair Model CL-600-2B19 series airplanes. One of these incidents resulted in engine shutdown during flight. Investigation revealed that the retaining ring, which restrains the CSD input shaft bearing, can become unseated from its positional groove on the input shaft. This condition could result in loss of IDG oil and subsequent disconnection of the IDG. In addition, the input shaft could move abnormally, which could cause damage to the engine seal. This condition, if not corrected, could result in loss of engine oil and subsequent engine shutdown during flight.
Bombardier Inc. has issued Canadair Regional Jet Alert Service Bulletin S.B.A601R-24-015, Revision 'A,' dated December 1, 1993, that describes procedures for repetitive inspections of the IDG oil level, and replenishing with oil, if necessary. For airplanes on which the IDG has been disconnected during flight, the alert service bulletin describes procedures for inspecting the oil level, and replacement of the IDG with a serviceable unit.
The alert service bulletin also references Canadair Regional Jet Alert Service Bulletin S.B.A601R-24-016, Revision 'A,' dated December 3, 1993, which describes procedures for accomplishment of a modification that would terminate the repetitive inspections and AFM revision. The modification involves installing a new bearing retainer and new input shaft bearings in the CSD units. Accomplishment of this modification will eliminate the loss of IDG oil and engine oil.
Transport Canada Aviation classified these alert service bulletins as mandatory and issued Canadian Airworthiness Directive CF-93-29, dated December 3, 1993, in order to assure the continued airworthiness of these airplanes in Canada.
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 and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, Transport Canada Aviation has kept the FAA informed of the situation described above. The FAA has examined the findings of Transport Canada Aviation, 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.
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 loss of engine oil and subsequent engine shutdown during flight.This AD revises the Limitations Section of the FAA-approved Airplane Flight Manual (AFM) to require that both IDG's be operational for dispatch. This AD also requires repetitive inspections of the IDG oil level, and replenishing with oil, if necessary. Additionally, for airplanes on which the IDG has been disconnected during flight, this AD requires replacement of the IDG with a serviceable unit. The inspections and replacement are required to be accomplished in accordance with Canadair Regional Jet Alert Service Bulletin S.B.A601R-24-015, described previously.
In addition, this AD provides an optional terminating modification, which, if accomplished, would terminate the repetitive oil level inspections and the AFM revision.
This is considered to be interim action. The FAA is considering further rulemaking action to require accomplishment of the optional terminating modification specified in this AD. However, the proposed compliance time for the modification is sufficiently long so that notice and opportunity for public comment would not be impracticable.
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 notice must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 93-NM-215-AD." The postcard will be date stamped and returned to the commenter.
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 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 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: