Airworthiness Directives; Airbus Model A310-200 and -300 Series Airplanes

AGENCY:

Federal Aviation Administration (FAA), Department of Transportation (DOT).

ACTION:

Notice of proposed rulemaking (NPRM).

SUMMARY:

The FAA proposes to adopt a new airworthiness directive (AD) for all Airbus Model A310-200 and -300 series airplanes. This proposed AD would require doing repetitive rotating probe inspections for any crack of the rear spar internal angle and the left and right sides of the tee fitting, and doing related investigative/corrective actions if necessary. This proposed AD would also require modifying the holes in the internal angle and tee fitting by cold expansion. This proposed AD results from full-scale fatigue tests, which revealed cracks in the lower rear spar internal angle, and tee fitting. We are proposing this AD to detect and correct fatigue cracks of the rear spar internal angle and tee fitting, which could lead to the rupture of the internal angle, tee fitting, and rear spar, and consequent reduced structural integrity of the wings.

DATES:

We must receive comments on this proposed AD by March 15, 2006.

ADDRESSES:

Use one of the following addresses to submit comments on this proposed AD.

• DOT Docket Web site: Go to http://dms.dot.gov and follow the instructions for sending your comments electronically.
• Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your comments electronically.
• Mail: Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street, SW., Nassif Building, room PL-401, Washington, DC 20590.
• Fax: (202) 493-2251.
• Hand Delivery: Room PL-401 on the plaza level of the Nassif Building, 400 Seventh Street, SW., Washington, DC, between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays.

Contact Airbus, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France, for service information identified in this proposed AD.

FOR FURTHER INFORMATION CONTACT:

Tim Backman, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; telephone (425) 227-2797; fax (425) 227-1149.

SUPPLEMENTARY INFORMATION:

Comments Invited

We invite you to submit any relevant written data, views, or arguments regarding this proposed AD. Send your comments to an address listed in the ADDRESSES section. Include the docket number “FAA-2006-23870; Directorate Identifier 2005-NM-022-AD” at the beginning of your comments. We specifically invite comments on the overall regulatory, economic, environmental, and energy aspects of the proposed AD. We will consider all comments received by the closing date and may amend the proposed AD in light of those comments.

We will post all comments we receive, without change, to http://dms.dot.gov,, including any personal information you provide. We will also post a report summarizing each substantive verbal contact with FAA personnel concerning this proposed AD. Using the search function of that web site, anyone can find and read the comments in any of our dockets, including the name of the individual who sent the comment (or signed the comment on behalf of an association, business, labor union, etc.). You may review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you may visit http://dms.dot.gov.

Examining the Docket

You may examine the AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility office between 9 a.m. and 5 p.m., Monday through Friday, except Federal holidays. The Docket Management Facility office (telephone (800) 647-5227) is located on the plaza level of the Nassif Building at the DOT street address stated in the ADDRESSES section. Comments will be available in the AD docket shortly after the Docket Management System receives them.

Discussion

The Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on all Airbus Model A310-200 and -300 series airplanes. During full-scale fatigue tests of the A310 airplane, the manufacturer found cracks at approximately 70,000 total flight cycles in the tee fitting at stiffener 8 on both sides of the center wing box, in the lower rear spar, and in the internal angles on both sides of the center wing box. DGAC advises that analysis of in-service inspections results has led the manufacturer to modify the existing inspection program, which is specified in action 1.14 of French airworthiness directive 1992-106-132(B) R6, dated June 25, 2003. The DGAC recommends that the thresholds and intervals be decreased and that a modification of the rear spar internal angle and tee fitting is needed to address fatigue cracks. Fatigue cracks of the rear spar internal angle and tee fitting, if not corrected, could lead to the rupture of the internal angle, tee fitting, and rear spar, and consequent reduced structural integrity of the wings.

Other Relevant Rulemaking

On December 8, 1998, we issued AD 98-26-01, amendment 39-10942 (63 FR 69179, December 16, 1998), for all Airbus Model A310 series airplanes, to require various inspections to detect fatigue cracks at certain locations on the fuselage, horizontal stabilizer, and wings and tail, and repair or modification, if necessary; and installation of doublers. Paragraph (o) of AD 98-26-01, for certain airplanes, requires repetitive rotating probe inspections to detect cracks in the fastener holes on the left- and right-hand sides of the rear spar internal angle and tee fitting, in accordance with Airbus Service Bulletin A310-57-2047, Revision 2, dated January 22, 1997. Certain actions in this proposed AD would terminate the requirements of paragraph (o) of AD 98-26-01.

Relevant Service Information

Airbus has issued Service Bulletin A310-57-2047, Revision 06, dated July 13, 2004. The service bulletin describes procedures for performing repetitive rotating probe inspections for any crack of the rear spar internal angle and the left and right sides of the tee fitting located in the center wing box, and doing related investigative and corrective actions if necessary. The corrective actions include oversizing holes, replacing bolts with new bolts, and contacting the manufacturer if any crack is beyond certain limits. The related investigative action is doing a rotating probe inspection for any crack after a hole has been oversized.

Airbus has also issued Service Bulletin A310-57-2035, Revision 08, dated September 19, 2005. The service bulletin describes procedures for modifying the holes in the internal angle and tee fitting by cold expansion (including doing related investigative and corrective actions). The related investigative and corrective actions include performing a rotating probe inspection for any crack of the bolt holes of the internal angle and tee fitting and contacting the manufacturer if any crack is found.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The DGAC mandated the service information and issued French airworthiness directive F-2005-001, dated January 5, 2005, to ensure the continued airworthiness of these airplanes in France.

FAA's Determination and Requirements of the Proposed AD

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. We have examined the DGAC's findings, evaluated all pertinent information, and determined that we need to issue an AD for airplanes of this type design that are certificated for operation in the United States.

Therefore, we are proposing this AD, which would require accomplishing the actions specified in the service information described previously, except as discussed under “Differences Between the Proposed AD and the Service Bulletins.”

Differences Between the Proposed AD and the Service Bulletins

The service bulletins specify to contact the manufacturer if certain cracks are found, but this proposed AD would require repairing those conditions using a method that we or the DGAC (or its delegated agent) approve. In light of the type of repair that would be required to address the unsafe condition, and consistent with existing bilateral airworthiness agreements, we have determined that, for this proposed AD, a repair we or the DGAC approve would be acceptable for compliance with this proposed AD.

Operators should also note that, unlike particular provisions in Airbus Service Bulletin A310-57-2047, Revision 06, dated July 13, 2004, regarding adjustment of the compliance times using an “inspection threshold formula, this proposed AD would not permit formulaic adjustments of the inspection compliance times. We have determined that such adjustments may present difficulties in determining if the initial inspection following installation of the modification in accordance with the service bulletin has been accomplished within the appropriate time frame. Further, while such adjustable compliance times are utilized as part of the Maintenance Review Board program, they do not fit practically into the AD tracking process for operators or for Principal Maintenance Inspectors attempting to ascertain compliance with ADs. Based on reviews of the “inspection threshold” calculations with the Aircraft Evaluation Group, and in further consultation with the manufacturer, we have determined that fixed compliance times should be specified for accomplishment of the actions specified in this proposed AD. However, operators may request an extension of the compliance times of this AD in accordance with the “inspection threshold” formula, under the provisions of paragraph (q) of this AD.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD. This proposed AD would affect about 56 airplanes of U.S. registry. Work hours and parts costs vary according to the configuration of the airplane.

Authority for This Rulemaking

Title 49 of the United States Code specifies the FAA's authority to issue rules on aviation safety. Subtitle I, section 106, describes the authority of the FAA Administrator. Subtitle VII, Aviation Programs, describes in more detail the scope of the Agency's authority.

We are issuing this rulemaking under the authority described in subtitle VII, part A, subpart III, section 44701, “General requirements.” Under that section, Congress charges the FAA with promoting safe flight of civil aircraft in air commerce by prescribing regulations for practices, methods, and procedures the Administrator finds necessary for safety in air commerce. This regulation is within the scope of that authority because it addresses an unsafe condition that is likely to exist or develop on products identified in this rulemaking action.

Regulatory Findings

We have determined that this proposed AD would not have federalism implications under Executive Order 13132. This proposed AD 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.

For the reasons discussed above, I certify that the 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. 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.

We prepared a regulatory evaluation of the estimated costs to comply with this proposed AD and placed it in the AD docket. See the ADDRESSES section for a location to examine the regulatory evaluation.

List of Subjects in 14 CFR Part 39

• Air transportation
• Aircraft
• Aviation safety
• Safety

The Proposed Amendment

Accordingly, under the authority delegated to me by the Administrator, the FAA proposes to amend 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.