01-18467. Airworthiness Directives; Airbus Model A310 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Final rule.

SUMMARY:

This amendment adopts a new airworthiness directive (AD), applicable to all Airbus Model A310 series airplanes, that requires 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. This amendment is prompted by reports of damaged metallic vapor seals observed during routine maintenance. This action is necessary to detect and correct damage to the metallic vapor seal in the center fuel tank, which could lead to leakage of fuel from the center tank into the air conditioning pack bay located below the center tank, providing a potential for fuel to be in contact with fuel ignition sources. This action is intended to address the identified unsafe condition.

DATES:

Effective September 4, 2001.

The incorporation by reference of certain publications listed in the regulations is approved by the Director of the Federal Register as of September 4, 2001.

ADDRESSES:

The service information referenced in this AD may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the Federal Aviation Administration (FAA), Transport Airplane Directorate, Rules Docket, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Ave. SW., Renton, Washington 98055-4056; telephone [phone]; fax [phone].

SUPPLEMENTARY INFORMATION:

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) of the 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 repetitive interval 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.

§ 39.13

[Amended]

2. Section 39.13 is amended by adding the following new airworthiness directive:

2001-15-13 Airbus Industrie: Amendment 39-12347. Docket 99-NM-234-AD.

Applicability: All Model A310 series airplanes, certificated in any category.

Note 1:

This AD applies to each airplane identified in the preceding applicability provision, regardless of whether it has been modified, altered, or repaired in the area subject to the requirements of this AD. For airplanes that have been modified, altered, or repaired so that the performance of the requirements of this AD is affected, the owner/operator must request approval for an alternative method of compliance in accordance with paragraph (d) of this AD. The request should include an assessment of the effect of the modification, alteration, or repair on the unsafe condition addressed by this AD; and, if the unsafe condition has not been eliminated, the request should include specific proposed actions to address it.

Compliance: Required as indicated, unless accomplished previously.

To detect and correct damage to the metallic vapor seal on the center fuel tank, which could lead to leakage of fuel from the center tank, providing a potential for fuel to be in contact with fuel ignition sources, accomplish the following:

Initial and Repetitive Inspection

(a) Prior to the accumulation of 16,000 total flight hours, or within 600 flight hours following the effective date of this AD, whichever occurs later: Conduct an initial detailed visual inspection of the metallic vapor seal for damage, in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-28-2138, dated June 28, 2000. Repeat the detailed visual inspection of the metallic vapor seal for damage thereafter at intervals not to exceed 600 flight hours.

Note 2:

For the purposes of this AD, a detailed visual inspection is defined as: “An intensive visual examination of a specific structural area, system, installation, or assembly to detect damage, failure, or irregularity. Available lighting is normally supplemented with a direct source of good lighting at intensity deemed appropriate by the inspector. Inspection aids such as mirror, magnifying lenses, etc., may be used. Surface cleaning and elaborate access procedures may be required.”

Note 3:

Accomplishment of an initial inspection and applicable corrective actions in accordance with Airbus All Operators Telex (AOT) A310-28A2139, dated April 8, 1999; or AOT A310-28A2139, Revision 01, dated April 26, 1999; is acceptable for compliance with the initial inspection required by paragraph (a) of this AD.

Corrective Action

(b) If damage to the metallic vapor seal is detected during any inspection required by paragraph (a) of this AD: Perform applicable corrective actions (including a temporary repair, a permanent repair, or replacement of a damaged metallic vapor seal) in accordance with the Accomplishment Instructions of Airbus Service Bulletin A310-28-2138, dated June 28, 2000. Any such corrective action must be performed within the compliance time specified in Figure 1 of the service bulletin. If no compliance time is specified in Figure 1, the applicable corrective action must be performed prior to the next flight.

(1) If a temporary repair is made to a metallic vapor seal: Perform the requirements of both paragraphs (b)(1)(i) and (b)(1)(ii).

(i) Repeat the inspection required by paragraph (a) of this AD at intervals not to exceed 600 flight hours.

(ii) Within 15 months after the date of the temporary repair, accomplish a permanent repair with removal of the metallic vapor seal. Thereafter, repeat the inspection required by paragraph (a) of this AD at intervals not to exceed 600 flight hours.

(2) If all parts of a metallic vapor seal are replaced simultaneously with new parts: The inspection required by paragraph (a) of this AD may be deferred during the next 16,000 flight hours. Thereafter, repeat the inspection at intervals not to exceed 600 flight hours.

Optional Terminating Action

(c) Replacement of metallic vapor seal panels with new, improved metallic vapor seal panels according to Airbus Service Bulletin A310-28-2146, dated March 27, 2001, constitutes terminating action for the actions required by this AD.

Alternative Methods of Compliance

(d) An alternative method of compliance or adjustment of the compliance time that provides an acceptable level of safety may be used if approved by the Manager, International Branch, ANM-116, FAA. Operators shall submit their requests through an appropriate FAA Principal Maintenance Inspector, who may add comments and then send it to the Manager, International Branch, ANM-116.

Note 4:

Information concerning the existence of approved alternative methods of compliance with this AD, if any, may be obtained from the International Branch, ANM-116.

Special Flight Permits

(e) Special flight permits may be issued in accordance with §§ 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 21.197 and 21.199) to operate the airplane to a location where the requirements of this AD can be accomplished.

Incorporation by Reference

(f) The actions shall be done in accordance with Airbus Service Bulletin A310-28-2138, dated June 28, 2000; and Airbus Service Bulletin A310-28-2146, dated March 27, 2001; as applicable. This incorporation by reference was approved by the Director of the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 51. Copies may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. Copies may be inspected at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington; or at the Office of the Federal Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

Note 5:

The subject of this AD is addressed in French airworthiness directive 2000-336-311(B), dated July 26, 2000.

Effective Date

(g) This amendment becomes effective on September 4, 2001.

Issued in Renton, Washington, on July 19, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.