Discussion
The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on all Airbus Model A330-200 and A330-300 series airplanes; and Model A340-200 and A340-300 series airplanes. The DGAC advises that it has received reports of elevator servo control removals resulting from the "F/CTL ELEV SERVO FAULT" warning. During repair, some of these servo controls installed at the active position (2CS1) (Left Green) or (2CS2) (Right Green) were found with a broken guide. The broken guides resulted in the inability for the affected servo controls to change their operating mode, leading to "F/CTL ELEV SERVO FAULT" warnings. Results of the investigation revealed a fatigue rupture inside the servo control induced by successive pressure cycles and resulting in a progressive decrease of the tightening torque of the plug to be the root cause of the broken guides.
Each elevator is equipped with two servo controls having three operating modes: active mode, damping mode, and centering mode. In normal operating conditions, each elevator is actuated by one servo control in active mode, while the other is in damping mode. The mode change from active to damping is achieved by a mode-selector spool valve installed inside each servo control. The position of this spool valve is commanded by a rod that slides through a guide. A broken guide could result in the inability for the affected servo control to change its operating mode.
Failure of the elevator servo controls during certain phases of takeoff, if not corrected, could result in an unannounced loss of elevator control and consequent reduced controllability of the airplane.
Relevant Service Information
Airbus has issued All Operators Telex (AOT) A330-27A3138, Revision 01, dated October 3, 2005, for Model A330-200 and -300 series airplanes; and AOT A340-27A4137, Revision 01, dated October 3, 2005,for Model A340-200 and -300 series airplanes. The AOTs describe procedures for repetitive tests of the elevator servo-loops and corrective actions if the test fails. If the test fails, the AOTs specify performing the associated troubleshooting manual tasks and applicable corrective actions. The corrective actions include repairing wiring, replacing certain solenoid valves, replacing certain mode selector valve transducers, and replacing the elevator servo control, among other actions, depending on the fault message displayed. The AOTs also specify reporting failed tests and sending replaced servo controls to Airbus.
The DGAC mandated the AOTs and issued French airworthiness directive UF-2005-171, dated October 3, 2005, to ensure the continued airworthiness of these airplanes in France.
FAA's Determination and Requirements of This AD
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. We have examined the DGAC's findings, evaluated all pertinent information, and determined that we need to issue an AD for products of this type design that are certificated for operation in the United States.
Therefore, we are issuing this AD to ensure proper functioning of the elevator servo controls. Failure of the elevator servo controls during certain phases of takeoff could result in an unannounced loss of elevator control and consequent reduced controllability of the airplane. This AD requires accomplishing the actions specified in the service information described previously.
This AD also requires that operators report results of failed servo-loop tests to Airbus. These required failed-test reports will be instrumental in ensuring that asmuch information as possible is gathered regarding the nature of the fatigue rupture causing the broken guides and that the new design of servo control to be used in a terminating modification, which the manufacturer is currently developing, will adequately address the subject unsafe condition.
Clarification of Corrective Actions Specified in the French Airworthiness Directive
The French airworthiness directive does not define what "corrective actions" should be taken when an elevator servo-loop test fails. We have verified that those corrective actions are the actions described previously under "Relevant Service Information."
Interim Action
We consider this AD interim action. The manufacturer is currently developing a modification that will address the unsafe condition identified in this AD. Once this modification is developed, approved, and available, we may consider additional rulemaking.
FAA's Determination of the Effective Date
An unsafe condition existsthat requires the immediate adoption of this AD; therefore, providing notice and opportunity for public comment before the AD is issued is impracticable, and good cause exists to make this AD effective in less than 30 days.
Comments Invited
This AD is a final rule that involves requirements that affect flight safety and was not preceded by notice and an opportunity for public comment; however, we invite you to submit any relevant written data, views, or arguments regarding this AD. Send your comments to an address listed in the ADDRESSES section. Include "Docket No. FAA-2005- 22881; Directorate Identifier 2005-NM-202-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD that might suggest a need to modify it.
We will post all comments we receive, without change, to http://dms.dot.gov , including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this AD. Using the search function of that Web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.
Examining the Docket
You may examine the AD docket on the Internet at http://dms.dot.gov , or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647- 5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.
Authority for This Rulemaking
Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.
We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, "General requirements." Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not havea substantial direct effect 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.
For the reasons discussed above, I certify that the regulation:
1. Is not a "significant regulatory action" under Executive Order 12866;
2. Is not a "significant rule" under the 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.
We prepared a regulatory evaluation of the estimated costs to comply with this AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by reference, Safety.
Adoption of the AmendmentAccordingly, under the authority delegated to me by the Administrator, the FAA amends 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.
Sec. 39.13 [Amended]
2. The Federal Aviation Administration (FAA) amends Sec. 39.13 by adding the following new airworthiness directive (AD):