The Luftfartsverket (LFV), which is the airworthiness authority for Sweden, recently notified the FAA that an unsafe condition may exist on certain Saab Model SAAB 2000 series airplanes. The LFV advises that it has received reports indicating that the de- icing system boots on the horizontal stabilizer do not always inflate fully in low temperatures. Condensational water, which collects in the stabilizer de-icing system, can freeze in low temperatures and prevent air from moving through the de-icing tube and properly inflating the boots. This condition, if not corrected, could result in failure of the de-icing system for the horizontal stabilizer, consequently leading to reduced controllability of the airplane.
In addition, the LFV has received reports indicating that the Engine Indication and Crew Alerting System (EICAS) displays in the cockpit continue to show that the de-icing system is operating properly although the stabilizer boots may not beinflating fully; consequently, the flightcrew is not aware that this system is not operating properly.
Explanation of Relevant Service Information
Saab has issued Service Bulletin SAAB 2000-30-006, dated December 22, 1995, which describes procedures for modifying the de-icing system tube. Modification is accomplished by drilling a hole in the tube. The LFV classified this service bulletin as mandatory and issued Swedish airworthiness directive (SAD) 1-084, dated January 3, 1996, in order to assure the continued airworthiness of these airplanes in Sweden.
In that SAD, the LFV also required repetitive visual inspections of the stabilizer de-icing boots prior to modification of the de-icing tube, and established conditions for conducting those inspections.
FAA's Conclusions
This airplane model is manufactured in Sweden and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.29) andthe applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LFV has kept the FAA informed of the situation described above. The FAA has examined the findings of the LFV, 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 Requirements of 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 condensational water from collecting in the tube of the de-icing system on the horizontal stabilizer. This AD requires repetitive visual inspections of the stabilizer de-icing boots after each flight to determine if they are operating fully. This AD also requires the de-icing tube to be modified by drilling a hole to allow condensational water to drain; such modification constitutes terminating action for the repetitive inspections. The modification is required to be accomplished in accordance with the service bulletin described previously.
Determination of Rule's Effective Date
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 rule must submit a self-addressed, stamped postcard on which the following statement is made: "Comments to Docket Number 96-NM-231-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.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and that it 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 thisemergency 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 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: