A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to all Airbus Model A310 series airplanes was published in the Federal Register on March 29, 2001 (66 FR 17127). That action proposed to require repetitive inspections of the metallic vapor seals in the center fuel tank to detect holes, tears, or a change in shape; corrective action, if such damage is detected; and follow-up tests for leaks.
Comments
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the comments received from a single commenter.
Add Terminating Action
The commenter requests that the FAA revise the proposed rule to include a terminating action. The commenter notes that Airbus has issued Service Bulletin A310-28-2146, dated March 27, 2001. That service bulletin states that, once the actions therein are accomplished, it cancels the inspection requirements of Airbus Service Bulletin A310-28-2138, dated June 28, 2000. (The proposed rule refers to that service bulletin as the appropriate source of service information.)
The FAA concurs. The Direction Generale de l'Aviation Civile (which is the airworthiness authority for France) has approved, and Airbus has recommended accomplishment of, Service Bulletin A310-28-2146, which describes procedures for replacement of metallic vapor seal panels with new, thicker metallic vapor seal panels. Such replacement raises the current fatigue life limitation on the metallic vapor seals and eliminates the need for the inspections required by this AD. Therefore, the FAA has revised this final rule to add a new paragraph (c) (and reorder subsequent paragraphs accordingly) to give operators the option to do the actions in that service bulletin as terminating action for the repetitive inspections required by this AD. Also, the FAA has added a new paragraph to the Cost Impact section in the preamble of this final rule to provide an estimate of the cost of this terminating action should an operator elect to do it.
Remove Reporting Requirement
The commenter requests that the FAA remove the reporting requirement that is specified in Airbus Service Bulletin A310-28-2138, dated June 28, 2000. The commenter states that the airplane manufacturer should already have adequate sampling data to understand the condition of the fleet, and, therefore, the reporting requirement is an unnecessary burden to the operator.
The FAA concurs with the intent of the commenter's request. However, the reporting requirement to which the commenter refers is not included in this AD, and the FAA cannot revise the referenced service bulletin. No change to the final rule is necessary in this regard.
Extend Repetitive Interval
The commenter requests that the FAA extend the repetitive interval for the repetitive inspections in paragraph (a) ofthe proposed AD from 600 to 750 flight hours. The commenter notes that its "B"-check interval is 350 flight hours, and the proposed 600-flight-hour interval would not allow for the proposed inspections to be done at a "2B"-check. Thus, it would not be able to do the inspections at a normal scheduled maintenance visit, which would negatively affect scheduling and increase the cost of the requirements of the proposed AD for the operator.
The FAA does not concur. The repetitive interval of 600 flight hours is based on in-service experience. Analysis has shown that damage of the vapor seal is related to vibration fatigue, probably caused by "drum beating" of the seal during operation of the airplane. A damaged vapor seal may no longer prevent fuels and vapors from coming into contact with hot parts of the air-conditioning packs, which could create a fire hazard. In view of these data, and the fact that the operator provides no technical data to show that a 750-flight-hour repetitiveinterval provides an acceptable level of safety, the FAA cannot extend the repetitive interval. No change to the final rule is necessary in this regard.
Allow Use of Equivalent Parts and Materials
The commenter requests that the FAA revise the proposed AD to allow operators to use equivalent and alternative parts and materials that are approved by the airplane manufacturer for repairs per this AD. The commenter states that this will eliminate the need for an operator to request an alternative method of compliance (AMOC) each time it needs to use materials other than those identified in the service bulletin.
The FAA does not concur. The referenced service bulletin refers to the Structural Repair Manual (SRM) as an additional source of service information for accomplishing certain requirements of this AD. Any alternative part or material beyond what is allowed by the SRM must be considered on a case-by-case basis; therefore, approval of an AMOC would be appropriate. No change to the final rule is necessary in this regard.
Conclusion
After careful review of the available data, including the comments noted above, the FAA has determined that air safety and the public interest require the adoption of the rule with the changes described previously. The FAA has determined that these changes will neither increase the economic burden on any operator nor increase the scope of the AD.
Cost Impact
The FAA estimates that 47 airplanes of U.S. registry will be affected by this AD, that it will take approximately 8 work hours per airplane to accomplish each inspection, and that the average labor rate is $60 per work hour. Based on these figures, the cost impact of the detailed visual inspections required by this AD on U.S. operators is estimated to be $22,560, or $480 per airplane, per inspection cycle.
The cost impact figure discussed above is based on assumptions that no operator has yet accomplished any of the requirements of this AD action, and that no operator would accomplish those actions in the future if this AD were not adopted. The cost impact figures discussed in AD rulemaking actions represent only the time necessary to perform the specific actions actually required by the AD. These figures typically do not include incidental costs, such as the time required to gain access and close up, planning time, or time necessitated by other administrative actions.
Should an operator elect to accomplish the replacement of metallic vapor seal panels that is provided as an optional terminating action in this AD, it would take approximately 25 work hours to accomplish, at an average labor rate of $60 per work hour. The cost of required parts would be approximately $7,720 per airplane. Based on these figures, the cost impact of the optional terminating action would be $9,220 per airplane.
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 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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new airworthiness directive: