01-7735. Airworthiness Directives; Airbus Model A310 Series Airplanes

AGENCY:

Federal Aviation Administration, DOT.

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

This document proposes the adoption of a new airworthiness directive (AD) that is applicable to all Airbus Model A310 series airplanes. This proposal would 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. The proposal 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:

Comments must be received by April 30, 2001.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-234-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056. Comments may be inspected at this location between 9:00 a.m. and 3:00 p.m., Monday through Friday, except Federal holidays. Comments may be submitted via fax to [phone]. Comments may also be sent via the Internet using the following address: [e-mail]. Comments sent via fax or the Internet must contain “Docket No. 99-NM-234-AD” in the subject line and need not be submitted in triplicate. Comments sent via the Internet as attached electronic files must be formatted in Microsoft Word 97 for Windows or ASCII text.

The service information referenced in the proposed rule may be obtained from Airbus Industrie, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. This information may be examined at the FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington.

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:

Comments Invited

Interested persons are invited to participate in the making of the proposed 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 above. All communications received on or before the closing date for comments, specified above, will be considered before taking action on the proposed rule. The proposals contained in this action may be changed in light of the comments received.

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 proposed 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 summarizing each FAA-public contact concerned with the substance of this proposal will be filed in the Rules Docket.

Commenters wishing the FAA to acknowledge receipt of their comments submitted in response to this action must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NM-234-AD.” The postcard will be date stamped and returned to the commenter.

Availability of NPRMs

Any person may obtain a copy of this NPRM by submitting a request to the FAA, Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-234-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on all Airbus Model A310 series airplanes. The DGAC advised that during routine maintenance, damage to metallic vapor seals in the center fuel tank on several airplanes had been observed. Inspection of the seals indicated that the damage resulted from metal fatigue, caused by vibration. This damage, if not corrected, 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.

Explanation of Relevant Service Information

Airbus has issued Service Bulletin A310-28-2138, dated June 28, 2000, which describes procedures for repetitive inspections of the metallic vapor seals on the center tank; corrective action, if damage is detected; and follow-up testing for leaks. The inspections include an initial detailed visual inspection and periodic follow-up inspections of the metallic vapor seals to detect holes, tears, or a change in shape. The corrective actions include temporary repair, permanent repair, and replacement of a damaged metallic vapor seal, as well as repair of the center fuel tank. The tests include a pressurization test of the vapor seal system and a leak test of the center fuel tank.

The service bulletin recommends that any temporary repair of a metallic vapor seal be replaced by a permanent repair within 15 months and that replacement of all 7 parts of a metallic vapor seal by new parts eliminates the need for inspection of that seal during the next 16,000 flight hours.

Accomplishment of the actions specified in the service bulletin is intended to adequately address the identified unsafe condition. The DGAC classified this service bulletin as mandatory and issued French airworthiness directive 2000-336-311(B), dated July 26, 2000, in order to assure the continued airworthiness of these airplanes in France.

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 21.29) and the applicable bilateral airworthiness agreement. Pursuant to this bilateral airworthiness agreement, the DGAC has kept the FAA informed of the situation described above. 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 Proposed Rule

Since an unsafe condition has been identified that is likely to exist or develop on other airplanes of the same type design registered in the United States, the proposed AD would require accomplishment of the actions specified in the service bulletin described previously.

Cost Impact

The FAA estimates that 47 airplanes of U.S. registry would be affected by this proposed AD, that it would 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 proposed detailed visual inspections 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 proposed requirements of this AD action, and that no operator would accomplish those actions in the future if this proposed 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.

Regulatory Impact

The regulations proposed herein would 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 proposal would not have federalism implications under Executive Order 13132.

For the reasons discussed above, I certify that this proposed 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) if promulgated, 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 copy of the draft regulatory evaluation prepared for this action is contained in the Rules Docket. A copy of it may be obtained by contacting the Rules Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, pursuant to the authority delegated to me by the Administrator, the Federal Aviation Administration proposes to amend 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:

Airbus Industrie: 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 (c) 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.

Alternative Methods of Compliance

(c) 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

(d) 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.

Note 5:

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

Issued in Renton, Washington, on March 23, 2001.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.