The Direction G n rale de l Aviation Civile (DGAC), which is the airworthiness authority for France, recently notified the FAA that an unsafe condition may exist on all Airbus Model A300, A310, and A300-600 series airplanes. One operator of an Airbus Model A300-600 reported high rudder forces and uncommanded rudder inputs during final approach. The uncommanded rudder inputs caused deflections of the rudder control surface resulting in yawing of the airplane. Investigation of the incident is ongoing, but preliminary results indicate that failure of both the main valve and the clutch valve of the autopilot yaw actuator can lead to the actuator generating uncommanded rudder deflections. The DGAC advises that the same autopilot actuator is used for roll and pitch control during autopilot operation, and this failure scenario can result in uncommanded deflections of the aileron and elevator control surfaces.
Preliminary results of the investigation of theincident airplane s autopilot yaw actuator indicate that the electrical connectors between the actuator s two main valves and the airplane s two flight control computers (FCC) were crossed between side 1 and side 2. This hidden failure in combination with a failure of the clutch valve resulted in the autopilot yaw actuator remaining engaged when the crew disconnected the autopilot, allowing the actuator to remain hydraulically pressurized and provide inputs to the rudder and the rudder pedals.
This condition, if not corrected, could result in uncommanded deflections of the ailerons, elevator, and/or rudder, which could result in reduced controllability of the airplane.
Explanation of Relevant Service Information
Airbus Industrie has issued All Operator Telexes (AOT) A300-22A0114 (for Model A300 series airplanes), A310-22A2050 (for Model A310 series airplanes), and A300-600-22A6039 (for Model A300-600 series airplanes); each dated May 27, 1999. These AOT s describe procedures for a one-time inspection of the autopilot systems for proper engagement to determine if the main electro valve electrical connectors of the yaw, roll, and pitch autopilot actuators are correctly installed. If autopilot systems 1 and 2 cannot be engaged, then the AOT s describe a visual inspection of the main electro valve electrical connectors of all autopilot actuators to determine whether any electrical connection is incorrectly installed; and corrective action by restoring the correct installation, if necessary. The DGAC classified these AOT s as mandatory and issued French airworthiness directive 1999-268-292(B), dated June 30, 1999; in order to assure the continued airworthiness of these airplanes in France.
FAA's Conclusions
These airplane models are manufactured in France and are 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 DGAC has kept the FAA informed of the situation described above. The FAA has examined the findings of the DGAC, 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 erratic movements of the ailerons, elevator, and/or rudder commanded by discrepant autopilot actuators, which could result in reduced controllability of the airplane. This AD requires accomplishment of the actions specified in the AOT s 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 99-NM-189-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 amongthe 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: