Transport Canada Aviation, which is the airworthiness authority for Canada, has notified the FAA that an unsafe condition may exist on all Canadair Model CL-215-1A10 series airplanes. Transport Canada Aviation advises that there has been an incident in which the water doors on one airplane inadvertently opened during flight. Investigation revealed that the cause of this malfunction of the doors was due to corrosion of the microswitches that are fitted to the water door actuators. The uncommanded opening of these doors at high speed during the takeoff run, water pick-up run, or landing run could cause serious damage to the airplane.
Explanation of Relevant Service Information
Canadair has issued Alert Service Bulletin 215-A363, dated March 16, 1987. This service bulletin describes procedures for (1) performing repetitive visual inspections to detect corrosion of the microswitches fitted to the water door actuator; (2) conducting repetitive resistance checks and insulation checks of the left-hand (LH) and right-hand (RH) water door actuator microswitches; and (3) replacing any discrepant microswitch. Transport Canada Aviation classified this service bulletin as mandatory and issued Canadian Airworthiness Directive CF-87-08 R1, dated December 7, 1990, in order to assure the continued airworthiness of these airplanes in Canada.
Canadair also has issued Service Bulletin 215-389, Revision 1, dated September 30, 1991, which describes procedures for modifying the water door microswitches. The modification entails replacing the LH and RH water door actuator microswitches, installing a relay channel and two relays, and modifying related wiring. Transport Canada Aviation has classified this service bulletin as "recommended."
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 CFR21.19) 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.
Explanation of the Requirements of the 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 the inadvertent opening of the water doors during flight due to the problems associated with corrosion of the microswitches fitted at the water door actuator. This AD requires repetitive inspections to detect discrepancies of these microswitches, and replacement of any discrepant microswitch. This AD requires modification of the water door microswitches as terminating action for the repetitive inspections The actions are required to be accomplished in accordance with the service bulletins described previously.
Differences Between this AD and Related Canadian AD
Operators should note that this AD differs from the related Canadian Airworthiness Directive CF-87-08 R1 in that this AD requires the accomplishment of the terminating action for the repetitive inspections of the microswitches. The FAA has determined that long term continued operational safety will be better assured by modifications or design changes to remove the source of the problem, rather than by repetitive inspections. Long term inspections may not be providing the degree of safety assurance necessary for the transport airplane fleet. This, coupled with a better understanding of the human factors associated with numerous repetitive inspections, has led the FAA to consider placing less emphasis on special procedures and more emphasis on design improvements. The modification requirement of this AD is in consonance with these considerations.
Cost Impact
None of the Model CL-215-1A10 series airplanes affected by this action are on the U.S. Register. All airplanes included in the applicability of this rule currently are operated by non-U.S. operators under foreign registry; therefore, they are not directly affected by this AD action. However, the FAA considers that this rule is necessary to ensure that the unsafe condition is addressed in the event that any of these subject airplanes are imported and placed on the U.S. Register in the future.
Should an affected airplane be imported and placed on the U.S. Register in the future, it would require approximately 2 work hours to accomplish the required inspections, at an average labor charge of $60 per work hour. Based on these figures, the cost impact of these required inspections would be $120 per airplane per inspection.
Accomplishment of the terminating modification would require approximately 40 work hours, at an average labor charge of $60 per work hour. Required parts would cost approximately $2,900 per airplane. Based on these figures, the cost impact of this required modification would be $5,300 per airplane.
Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently on the U.S. register, it has no adverse economic impact and imposes no additional burden on any person. Therefore, notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.
Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and 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 96-NM-61-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.
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: