The Luftfahrt-Bundesamt (LBA), which is the airworthiness authority for Germany, recently notified the FAA that an unsafe condition may exist on all Dornier Model 328-100 series airplanes. The LBA advises that, during takeoff of a flight test airplane, an uncommanded retraction of the flaps occurred, which resulted in an aborted takeoff. Investigation revealed that the flaps can inadvertently move downward due to gravity while the airplane is on the ground. This movement creates a vacuum in the flap actuator expansion chamber. The existence of such a vacuum can cause an uncommanded retraction of the flaps during takeoff with a corresponding takeoff config warning to the flightcrew. This condition, if not corrected, could result in an aborted takeoff and consequent potential for runway overrun.
Explanation of Relevant Service Information
The manufacturer has issued Dornier 328 All Operators Telefax (AOT) AOT-328-27-016, dated July 31, 1998. TheAOT describes procedures for revising the Normal and Abnormal Procedures Sections of the Airplane Flight Manual (AFM) to provide the flightcrew with additional information for resetting the flap system to ensure complete pressurization of the hydraulic lines for the flaps. The LBA classified this AOT as mandatory and issued German airworthiness directive 1998-359, dated September 10, 1998, in order to assure the continued airworthiness of these airplanes in Germany.
FAA's Conclusions
This airplane model is manufactured in Germany 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) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the LBA has kept the FAA informed of the situation described above. The FAA has examined the findings of the LBA, 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 an uncommanded retraction of the flaps during takeoff, which could result in an aborted takeoff and consequent potential for runway overrun. This AD requires revising the Normal Procedures and Abnormal Procedures Sections of the FAA-approved Dornier 328 AFM to provide the flightcrew with additional information regarding procedures to ensure complete pressurization of the hydraulic lines for the flaps.
Interim Action
This is considered to be interim action. The manufacturer has advised that it currently is developing a hardware modification that will positively address the unsafe condition addressed by this AD. Once this modification is developed, approved, and available, the FAA may consider additional rulemaking.
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 98-NM-305-AD." The postcard will be date stamped and returned to the commenter.
Regulatory ImpactThe 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 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 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: