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- 223, -321, -322, and -323 series airplanes equipped with Pratt & Whitney Model PW4164, PW4168, or PW4168A engines. The DGAC advises that engine fan blade-out tests performed by the engine manufacturer, Pratt &Whitney, have shown that the loads used for certification of the engines were underestimated. In the event of an engine fan blade-out, the induced loads could lead to reduced structural integrity of the primary structure of the engine pylons, and uncommanded deployment of the thrust reversers. This condition, if not corrected, could result in reduced controllability of the airplane.
Explanation of Relevant Service Information
Airbus has issued Service Bulletin A330-54-3016, Revision 01, dated August 7, 2000, which describes procedures for the modification of the primary structure of the engine pylons. The modification includes, among other actions, replacing the stainless steel screws at rib 8B and rib 12 with Inconel screws, and replacing the stainless steel screws located on the lateral panel seam of the lower spar between rib 8C and rib 10 with stainless steel screws of the next-higher-nominal diameter.
Airbus has also issued Service Bulletin A330-78-3011, dated December 14, 1999, which describes procedures for the replacement of the thrust reverser locking actuators with new, improved locking actuators.
Accomplishment of the actions specified in these service bulletins is intended to adequately address the identified unsafe condition. The DGAC classified these service bulletins as mandatory and issued French airworthiness directive 2000-237-123(B) R1, dated December 12, 2001, in order to assure the continued airworthiness of these airplanes in France.
Airbus Service Bulletin A330-78-3011, dated December 14, 1999, references Pratt & Whitney Service Bulletin PW4G-100-78-71, dated September 24, 1999, as an additional source of service information for accomplishment of the replacement of the thrust reverser locking actuators.
FAA's Conclusions
This airplane model is manufactured in France and is type certificated for operation in the United States under the provisions of section 21.29 of the Federal Aviation Regulations (14 CFR 21.19) 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 the Rule
Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design that may be registered in the United States at some time in the future, this AD is being issued to prevent the reduced structural integrity of the primary structure of the engine pylons, and uncommanded deployment of the thrust reversers, which could result in reduced controllability of the airplane. This AD requires accomplishment of the actions specified in the service bulletins described previously, except as discussed below.
Differences Between this AD and the French Airworthiness Directive
This AD differs from the parallel French airworthiness directive in that it will not require repetitive visual inspections of the fan blades at intervals not to exceed 500 engine hours, or an ultrasonic inspection of the attachment area of the fan blade root before the accumulation of 5,000 parts cycles since new, or within 500 parts cycles after the effective date of the French airworthiness directive. These inspections are not associated with any known unsafe condition. The DGAC required these inspections to minimize the possibility of a fan blade-off event, pending the retrofit of the modifications in paragraph 3 of the French airworthiness directive. All Airbus Model A330-223, -321, -322, and -323 series airplanes of U.S. registry were delivered with the modifications installed.
The French airworthiness directive defers implementation of the mandatory actions (i.e., modification of the engine pylon and replacement of the thrust reverser locking actuators) for a period of time by requiring the inspections described in the preceding paragraph. The compliance time for accomplishment of the mandatory actions is before the accumulation of 8,000 flight cycles since new, or before August 1, 2004, whichever occurs first. The DGAC advises that if the inspections in the preceding paragraph are not mandated, the modifications must be accomplished in a timeframe comparable to that of the inspections. Therefore, this AD requires accomplishment of the mandatory actions within 500 engine hours or six months after the effective date of this AD, whichever occurs later.
Operators should note that, unlike the French airworthiness directive, this AD will not require the replacement of the pylon aft mount nuts and bolts since the manufacturer has confirmed to the FAA that all pylon aft mount nuts and bolts made of MP159 material have already been replaced. Additionally, the French airworthiness directive requires replacement of the pylon front mount bolts made of MP159 material. The FAA has determined through review of data provided by the engine manufacturer that repetitive inspection of front mount bolts made of MP159 material addresses the unsafe condition. As discussed below, the FAA previously issued two other ADs that require these actions.
These differences have been coordinated with and acknowledged by the DGAC.
Other Relevant Rulemaking
The FAA has previously issued two other ADs that concern the pylon aft and forward mount nuts and bolts on Airbus airplanes:
1. AD 2000-25-53, amendment 39-12051 (65 FR 82259, December 28, 2000), requires repetitive inspections for cracks or other damage of pylon aft mount nuts and bolts made of MP159 material.
2. AD 2000-16-02, amendment 39-11856 (65 FR 49730, August 15, 2000), requires repetitive inspections and
torque checks for loose or broken pylon forward mount bolts made from INCO 718 material and establishes a new life limit for these bolts. The AD also requires repetitive inspections of pylon forward mount bolts made from MP159 material.
However, this AD will not affect the current requirements of either of those previously issued ADs.
Cost Impact
The FAA estimates that 9 airplanes of U.S. registry will be affected by this AD. The FAA has been advised that the 9 affected airplanes have been modified in accordance with the requirements of this AD. Therefore, currently, this AD action imposes no additional economic burden on any U.S. operator.
However, should an unmodified airplane be imported and placed on the U.S. Register in the future, it will take approximately 51 work hours per airplane to accomplish the actions, at an average labor rate of $60 per work hour. Required parts will be supplied by the manufacturer to the operators at no cost. Based on these figures, the cost impact of the AD is estimated to be $3,060 per airplane.
Determination of Rule's Effective Date
Since this AD action does not affect any airplane that is currently on the U.S. registry, it has no adverse economic impact and imposes no additional burden on any person. Therefore, prior notice and public procedures hereon are unnecessary and the amendment may be made effective in less than 30 days after publication in the Federal Register.
Comments Invited
Although this action is in the form of a final rule and was not preceded by notice and opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment onthis 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.
Submit comments using the following format:
Organize comments issue-by-issue. For example, discuss a request to change the compliance time and a request to change the service bulletin reference as two separate issues.
For each issue, state what specific change to the proposed AD is being requested.
Include justification (e.g., reasons or data) for each request.
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 2002-NM-102-AD.'' The postcard will be date stamped and returned to the commenter.
Regulatory Impact
The regulations adopted herein 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.Therefore, it is determined that this final rule does not have federalism implications under Executive Order 13132.
For the reasons discussed above, I certify that this action (1) is not a ``significant regulatory action'' under Executive Order 12866; (2) is not a ``significant rule'' under 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. A final evaluation has been prepared for this action and it is contained in the Rules Docket. A copy of it 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 AviationAdministration 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: