The Direction Generale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Airbus Model A330, A340-200, and A340-300 series airplanes. The DGAC advises that it has received a report of the flightcrew on a Model A330 series airplane doing a free-fall extension of the main landing gear (MLG) during approach. Investigation revealed a rupture of the piston rod for the left MLG retraction actuator. It was determined that corrosion and cracking caused the rupture. Additional reports indicate that cracking was found on the chromed area of several piston rods; the cracking started from a line of corrosion pitting in the rod bores. These conditions, if not corrected, could result in rupture of a piston rod, non-damped extension of the MLG, and high loads on the fully extended MLG, which could result in reduced structural integrity of the MLG.
The MLG system on Model A340-200and A340-300 series airplanes is identical to the MLG system on the affected Model A330 series airplanes. Therefore, Model A340-200 and A340-300 series airplanes may be subject to the same unsafe condition identified on the Model A330 series airplanes.
Relevant Service Information
Airbus has issued Service Bulletin A330-32-3173, Revision 01 (for Model A330 series airplanes); and A340-32-4212, Revision 01 (for Model A340-200 and -300 series airplanes); both dated June 16, 2004. The service bulletins describe procedures for repetitive detailed visual inspections for cracking of the chromed area of the left and right piston rods for the MLG retraction actuators. If any cracking is found, the corrective actions include replacing the
affected MLG retraction actuator with a new actuator before the next flight.
The service bulletins also describe procedures for related investigative actions. Those procedures include repetitive ultrasonic inspections for corrosion pitting and cracking of the inner surface of the piston rods for the MLG retraction actuators. If any corrosion pitting or cracking is found, the corrective actions include replacing the affected MLG retraction actuator with a new actuator. The compliance time for the corrective action depends on the results of the ultrasonic inspection, and is either before the next flight, or within the next 10 landings.
The service bulletins also include procedures for reporting the results of both the detailed visual and ultrasonic inspections to Airbus.
The DGAC mandated these service bulletins and issued French airworthiness directives F-2004-086 and F-2004-087, both dated June 23, 2004, to ensure the continued airworthiness of these airplanes in France.
Both of the Airbus service bulletins reference Messier-Dowty Service Bulletin A33/34-32-222, including Appendices A and B, dated December 6, 2003, as an additional source of service information for the detailed visual and ultrasonic inspections.
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 AD action is necessary for products of this type design that are certificated for operation in the United States. Therefore, we are issuing this AD to detect and correct corrosion pitting and cracking of the piston rods for the MLG retraction actuators, which could result in rupture of the piston rods, non-damped extension of the MLG, high loads on the fully extended MLG, and consequent reduced structural integrity of the MLG.
This AD requires doing the actions specified in the Airbus service information described previously, except as discussed under "Differences Between the AD and French Airworthiness Directives." This AD also requires sending certain inspection results to the manufacturer.
Interim Action
We consider this AD to be interim action. The inspection reports that are required by this AD will enable the manufacturer to obtain better insight into the nature, cause, and extent of the corrosion/ cracking, and eventually to develop final action to address the unsafe condition. Once final action has been identified, we may consider further rulemaking.
Differences Between the AD and French Airworthiness Directives
The French airworthiness directives do not include compliance times for airplanes equipped with piston rods that have been in service less than 36 months, as of the effective date of the French airworthiness directives. However, the FAA AD includes compliance times for these airplanes. Because this AD is an interim action, we have determined that it is necessary to address airplanes equipped with piston rods that are close to having 36 months in service, as of the effective date of the AD. This difference has been coordinated with the DGAC.
Clarification of Inspection Terminology
The Airbus service bulletins specify to do a "detailed visual inspection" of the chromed area of the piston rods for the MLG retraction actuators. This AD instead requires a "detailed inspection," which is defined in Note 1 of this AD.
FAA's Determination of the Effective Date
An unsafe condition exists that 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 written relevant data, views, or arguments regarding this AD. Send your comments to an address listed under ADDRESSES. Include "Docket No. FAA-2004-18669; Directorate Identifier 2004-NM-83-AD" at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the AD. We will consider all comments received by the closing date and may amend the AD in light of those comments.
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 our docket 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 can review the DOT'scomplete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.
We are reviewing the writing style we currently use in regulatory documents. We are interested in your comments on whether the style of this document is clear, and your suggestions to improve the clarity of our communications with you. You can get more information about plain language at http://www/faa.gov/language and http://www.plainlanguage.gov.
Regulatory Findings
We have determined that this AD will not have federalism implications under Executive Order 13132. This AD will not have a 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. 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 Amendment
Accordingly, 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 FAA amends Sec. 39.13 by adding the following new airworthiness directive(AD):