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Proposed Rule

Airworthiness Directives; Airbus Model A300, A310, and A300-600 Series Airplanes

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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 A300, A310, and A300-600 series airplanes. This proposal would require an inspection to detect damage of the electrical bonding leads in specified locations of the fuel tanks, and replacement of any damaged electrical bonding leads with serviceable electrical bonding leads. For certain airplanes, this proposal also would require modifying the fuel pipe couplings in specified locations of the fuel tank. This proposal is prompted by issuance of mandatory continuing airworthiness information by a foreign civil airworthiness authority. The actions specified by the proposed AD are intended to prevent electrical arcing/discharge in the fuel tank due to damaged electrical bonding leads or inadequate electrical bonding of the fuel pipe couplings, which could result in fuel ignition and consequent uncontained rupture of the fuel tank.

DATES:

Comments must be received by April 26, 2000.

ADDRESSES:

Submit comments in triplicate to the Federal Aviation Administration (FAA), Transport Airplane Directorate, ANM-114, Attention: Rules Docket No. 99-NM-128-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.

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.

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FOR FURTHER INFORMATION CONTACT:

Norman B. Martenson, Manager, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2110; fax (425) 227-1149.

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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 notice may be changed in light of the comments received.

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 notice must submit a self-addressed, stamped postcard on which the following statement is made: “Comments to Docket Number 99-NM-128-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-128-AD, 1601 Lind Avenue, SW., Renton, Washington 98055-4056.

Discussion

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 all Airbus Model A300, A310, and A300-600 series airplanes. The DGAC advises that, during a maintenance check, an inspection of the inner fuel tanks revealed damage (i.e., breakage and corrosion) to several bonding leads. The damage is a result of normal aging of the bonding leads. Damaged bonding leads could create electrical voltage differentials between the fuel tank components, which could result in electrical arcing inside the fuel tanks. The DGAC advises that electrical arcing also could occur between certain fuel pipe couplings inside the fuel tanks due to their existing design. These conditions, if not corrected, could result in fuel ignition and consequent uncontained rupture of the fuel tank.

Explanation of Relevant Service Information

Airbus has issued Service Bulletins A300-28-0072, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A300 series airplanes); A310-28-2128, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A310 series airplanes); and A300-28-6057, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A300-600 series airplanes). These service bulletins describe procedures for inspection of the electrical bonding leads in specified locations of the fuel tank for damage (i.e., breakage, fraying, abrasion damage, looseness of the outer metal braid protection in the end crimp, looseness of the outer metal braid protection on the bonding lead inner core, corrosion, or missing leads), and replacement of any damaged electrical bonding lead with a serviceable electrical bonding lead.

Also, Airbus has issued Service Bulletins A300-28-0073, Revision 01, dated October 01, 1998 (for Model A300 Start Printed Page 16152series airplanes); A310-28-2130, Revision 01, dated October 01, 1998 (for Model A310 series airplanes); and A300-28-6058, Revision 01, dated October 01, 1998 (for Model A300-600 series airplanes). For certain airplanes these service bulletins describe procedures for modifying the fuel pipe couplings in specified locations of the fuel tank by removing one bolt from each flanged fuel pipe coupling and reinstalling it as an electrical bonding bolt.

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 98-174-248(B), dated April 22, 1998, in order to assure the continued airworthiness of these airplanes in France.

FAA's Conclusions

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. 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 bulletins described previously, except as discussed below.

Difference Between Proposed Rule and Foreign Airworthiness Directive

Operators should note that, although the service bulletin and French airworthiness directive recommend that the modification be accomplished within 4 years (after the release of the service bulletin), the FAA has determined that an interval of 4 years would not address the identified unsafe condition in a timely manner.

An electrical discharge in a fuel tank can create a spark that could ignite the fuel vapors inside the tank. The spark energy required to ignite fuel depends on the type of fuel, the fuel temperature, and the air pressure (altitude) inside a fuel tank. Under certain conditions, fuel can be ignited with spark energy levels much lower than the energy required to create a visible mark. Therefore, a spark that has enough energy to cause a mark can ignite fuel vapor under a wider range of fuel tank conditions.

In developing an appropriate compliance time for this AD, the FAA considered not only the manufacturer's recommendation, but the degree of urgency associated with addressing the subject unsafe condition, the average utilization of the affected fleet, and the time necessary to perform the modification. In light of all of these factors, the FAA finds a 36-month compliance time for accomplishing the inspection and modification to be warranted, in that 36 months represent an appropriate interval of time allowable for affected airplanes to continue to operate without compromising safety.

Cost Impact

The FAA estimates that 116 airplanes of U.S. registry would be affected by this proposed AD.

It would take between 70 and 80 work hours per airplane to accomplish the proposed inspection, at an average labor rate of $60 per work hour. Based on these figures, the cost impact of the proposed inspection on U.S. operators is estimated to be between $487,200 and $556,800, or between $4,200 and $4,800 per airplane.

It would take between 77 and 103 work hours per airplane to accomplish the proposed modification, at an average labor rate of $60 per work hour. Required parts would cost approximately $104 per airplane. Based on these figures, the cost impact of the proposed modification on U.S. operators is estimated to be between $547,984 and $728,944, or between $4,724 and $6,284 per airplane.

The cost impact figures discussed above are 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 AD were not adopted.

Regulatory Impact

The regulations proposed herein would not have substantial direct effects 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, in accordance with Executive Order 12612, it is determined that this proposal would not have sufficient federalism implications to warrant the preparation of a Federalism Assessment.

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.

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List of Subjects in 14 CFR Part 39

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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:

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PART 39—AIRWORTHINESS DIRECTIVES

1. The authority citation for part 39 continues to read as follows:

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Authority: 49 U.S.C. 106(g), 40113, 44701.

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[Amended]

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

Airbus Industrie: Docket 99-NM-128-AD.

Applicability: All Model A300, A310, and A300-600 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 prevent electrical arcing/discharge in the fuel tank due to damaged Start Printed Page 16153electrical bonding leads or inadequate electrical bonding of the fuel pipe couplings, which could result in fuel ignition and consequent uncontained rupture of the fuel tank, accomplish the following:

(a) Within 36 months after the effective date of this AD, perform a one-time inspection to detect damage (i.e., breakage, fraying, abrasion damage, looseness of the outer metal braid protection in the end crimp, looseness of the outer metal braid protection on the bonding lead inner core, corrosion, or missing leads) of the electrical bonding leads in specified locations of the fuel tanks, in accordance with the Accomplishment Instructions of Airbus Service Bulletins A300-28-0072, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A300 series airplanes); A310-28-2128, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A310 series airplanes); or A300-28-6057, Revision 01, dated October 01, 1998, including Appendix 1, dated October 01, 1998, and Appendix 2, dated February 20, 1998 (for Model A300-600 series airplanes); as applicable.

Note 2:

Inspection of the area specified in paragraph (a) of this AD accomplished prior the effective date of this AD in accordance with Airbus Service Bulletins A300-28-0072, A310-28-2128, or A300-28-6057; all dated February 20, 1998; as applicable; is considered acceptable for compliance with the requirements of paragraph (a) of this AD.

(b) If any electrical bonding lead is damaged, prior to further flight, replace the bonding lead with a serviceable bonding lead in accordance with the applicable service bulletin specified in paragraph (a) of this AD.

(c) For airplanes on which Airbus Industrie Modification 11847 (for Model A310 series airplanes) or 11848 (for Model A300/A300-600 series airplanes) has not been accomplished, within 36 months after the effective date of this AD, modify the fuel pipe couplings in the specified locations of the fuel tank in accordance with the Accomplishment Instructions of Airbus Service Bulletins A300-28-0073, Revision 01, dated October 01, 1998 (for Model A300 series airplanes); A310-28-2130, Revision 01, dated October 01, 1998 (for Model A310 series airplanes); or A300-28-6058, Revision 01, dated October 01, 1998 (for Model A300-600 series airplanes); as applicable.

Note 3:

Modification of the fuel pipe couplings accomplished prior to the effective date of this AD in accordance with Airbus Service Bulletins A300-28-0073, A310-28-2130, or A300-28-6058; all dated February 20, 1998; as applicable; is considered acceptable for compliance with the requirements of paragraph (c) of this AD.

(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, Transport Airplane Directorate. 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 sections 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 98-174-248(B), dated April 22, 1998.

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Issued in Renton, Washington, on March 20, 2000.

Donald L. Riggin,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.

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[FR Doc. 00-7337 Filed 3-24-00; 8:45 am]

BILLING CODE 4910-13-U