06-5872. Airworthiness Directives; Airbus Model A300 and A310 Airplanes; and Airbus Model A300 B4-600, B4-600R, and F4-600R Series Airplanes, and Model C4-605R Variant F Airplanes (Collectively Called A300-600 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 A300 and A310 airplanes and A300-600 series airplanes. This proposed AD would require inspecting for discrepancies of all electrical bundles located in the leading and trailing edges of the wings, and performing corrective actions if necessary. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to prevent an ignition source, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by July 31, 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: [phone].
• 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:

Tom Stafford, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98057-3356; telephone [phone]; fax [phone].

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-2006-25221; Directorate Identifier 2006-NM-122-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 [phone]) 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 FAA has examined the underlying safety issues involved in fuel tank explosions on several large transport airplanes, including the adequacy of existing regulations, the service history of airplanes subject to those regulations, and existing maintenance practices for fuel tank systems. As a result of those findings, we issued a regulation titled “Transport Airplane Fuel Tank System Design Review, Flammability Reduction and Maintenance and Inspection Requirements' (66 FR 23086, May 7, 2001). In addition to new airworthiness standards for transport airplanes and new maintenance requirements, this rule included Special Federal Aviation Regulation No. 88 (“SFAR 88,” Amendment 21-78, and subsequent Amendments 21-82 and 21-83).

Among other actions, SFAR 88 requires certain type design (i.e., type certificate (TC) and supplemental type certificate (STC)) holders to substantiate that their fuel tank systems can prevent ignition sources in the fuel tanks. This requirement applies to type design holders for large turbine-powered transport airplanes and for subsequent modifications to those airplanes. It requires them to perform design reviews and to develop design changes and maintenance procedures if their designs do not meet the new fuel tank safety standards. As explained in the preamble to the rule, we intended to adopt airworthiness directives to mandate any changes found necessary to address unsafe conditions identified as a result of these reviews.

In evaluating these design reviews, we have established four criteria intended to define the unsafe conditions associated with fuel tank systems that require corrective actions. The percentage of operating time during which fuel tanks are exposed to flammable conditions is one of these criteria. The other three criteria address the failure types under evaluation: Single failures, single failures in combination with a latent condition(s), and in-service failure experience. For all four criteria, the evaluations included consideration of previous actions taken that may mitigate the need for further action.

The Joint Aviation Authorities (JAA) has issued a regulation that is similar to SFAR 88. (The JAA is an associated body of the European Civil Aviation Conference (ECAC) representing the civil aviation regulatory authorities of a number of European States who have agreed to co-operate in developing and implementing common safety regulatory standards and procedures.) Under this regulation, the JAA stated that all members of the ECAC that hold type certificates for transport category airplanes are required to conduct a design review against explosion risks.

We have determined that the actions identified in this AD are necessary to reduce the potential of ignition sources inside fuel tanks, which, in combination with flammable fuel vapors, could result in fuel tank explosions and consequent loss of the airplane.

The European Aviation Safety Agency (EASA) notified us that an unsafe condition may exist on all Airbus Model A300 and A310 airplanes; and Airbus Model A300 B4-600, B4-600R, and F4-600R series airplanes, and Model C4-605R Variant F airplanes (collectively called A300-600 series airplanes). The EASA advises us of the potential for discrepancies, including but not limited to chafing, of all electrical bundles in the leading and trailing edges of the wings of these airplanes. This condition, if not corrected, could result in an ignition source, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Relevant Service Information

Airbus has issued the service bulletins listed in the table below.

Airplane model	Airbus service bulletin, including appendix 01	Date
A300	A300-24-0102	December 15, 2005.
A310	A310-24-2095	December 15, 2005.
A300-600 series	A300-24-6092	December 15, 2005.

These service bulletins describe procedures for performing detailed inspections for discrepancies of all electrical bundles located in the leading and trailing edges of the wings, and corrective actions if necessary. The inspections include inspecting for the following:

• Inadequate clearance between electrical wire harnesses and adjacent components or structure, including support structure, stringers, fasteners, pipes, bonding leads, or any metallic component which could create a conductive path to structure.
• Evidence of chafing of electrical cable harnesses.
• Discrepancies of clamps (including, but not limited to, unacceptable condition, unacceptable condition of cushioning and anti-chafing devices, or evidence of chafing against electrical cable harnesses).
• Discrepancies of cable ties (including, but not limited to, unacceptable condition, or evidence of chafing against electrical cable harnesses).
• Discrepancies of convoluted conduits (including, but not limited to, unacceptable condition, evidence of chafing against electrical cable harnesses, and absence of drainage holes in the conduits).
• Discrepancies of metallic conduits (including, but not limited to, unacceptable condition, evidence of chafing against electrical cable harnesses, and absence of or unacceptable condition of drainage holes in the conduits).

Corrective actions include repairing any chafed electrical cable harnesses, replacing discrepant clamps with new clamps, repairing or replacing discrepant cable ties, installing drainage holes in convoluted or metallic conduits, and repairing any discrepant convoluted or metallic conduits. If clearance is not adequate between electrical wire harnesses and adjacent components or structure, the service bulletins specify contacting Airbus for corrective action. The service bulletins also specify to report all findings to Airbus.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The EASA mandated the service information and issued airworthiness directive 2006-0076, dated April 3, 2006, to ensure the continued airworthiness of these airplanes in the European Union.

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. As described in FAA Order 8100.14A, “Interim Procedures for Working with the European Community on Airworthiness Certification and Continued Airworthiness,” dated August 12, 2005, the EASA has kept the FAA informed of the situation described above. We have examined the EASA's findings, evaluated all pertinent information, and determined that we need to issue an AD for products 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 Service Information.” The proposed AD would also require sending the inspection results to Airbus.

Differences Between the Proposed AD and Service Information

The service bulletins specify to contact the manufacturer for instructions on how to correct inadequate clearance between electrical wire harnesses and adjacent components or structure and repair certain conditions, but this proposed AD would require correcting that condition using a method that we or the EASA (or its delegated agent) approve. In light of the type of corrective action 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 corrective action that we or the EASA approve would be acceptable for compliance with this proposed AD.

Clarification of Inspection Terminology

In this proposed AD, the “detailed visual inspection” specified in the EASA's AD and the Airbus service bulletins is referred to as a “detailed inspection.” We have included the definition for a detailed inspection in a note in the proposed AD.

Costs of Compliance

This proposed AD would affect about 227 airplanes of U.S. registry. The proposed actions would take about 10 work hours per airplane, at an average labor rate of $80 per work hour. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $181,600, or $800 per 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.

§ 39.13

[Amended]

2. The Federal Aviation Administration (FAA) amends § 39.13 by adding the following new airworthiness directive (AD):

Airbus: Docket No. FAA-2006-25221; Directorate Identifier 2006-NM-122-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by July 31, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to all Airbus Model A300 and A310 airplanes; and all Airbus Model A300 B4-601, B4-603, B4-620, B4-622, B4-605R, B4-622R, F4-605R, and F4-622R airplanes, and A300 C4-605R Variant F airplanes; certificated in any category.

Unsafe Condition

(d) This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent an ignition source, which, in combination with flammable fuel vapors, could result in a fuel tank explosion and consequent loss of the airplane.

Compliance

(e) You are responsible for having the actions required by this AD performed within the compliance times specified, unless the actions have already been done.

Service Bulletin Reference

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the following service bulletins, as applicable:

(1) For Model A300 airplanes: Airbus Service Bulletin A300-24-0102, including Appendix 01, dated December 15, 2005;

(2) For Model A310 airplanes: Airbus Service Bulletin A310-24-2095, including Appendix 01, dated December 15, 2005; and

(3) For Model A300 B4-601, B4-603, B4-620, B4-622, B4-605R, B4-622R, F4-605R, and F4-622R airplanes, and A300 C4-605R Variant F airplanes: Airbus Service Bulletin A300-24-6092, including Appendix 01, dated December 15, 2005.

Inspections and Corrective Actions

(g) Within 44 months after the effective date of this AD, perform detailed inspections for discrepancies of all electrical bundles located in the leading and trailing edges of the wings, and all applicable corrective actions, by doing all of the actions in the service bulletin, except as provided by paragraph (h) of this AD. All corrective actions must be done before further flight.

Note 1:

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

Exception to Corrective Action Instructions

(h) If inadequate clearance is found between any electrical wire harness and adjacent components or structure: Before further flight, correct the inadequate clearance using a method approved by either the Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA; or the European Aviation Safety Agency (EASA) (or its delegated agent).

Reporting

(i) Within 30 days after doing the inspections required by this AD, or within 30 days after the effective date of the AD, whichever is later: Submit a report of the findings (both positive and negative) of the inspections required by paragraph (g) of this AD to Airbus Engineering, c/o SE-E54, 1 Rond Point Maurice Bellonte, 31707 Blagnac Cedex, France. The report must include the airplane serial number or registration number, the number of flight cycles and flight hours on the airplane, the date of the inspection, the location of the defect, the conditions found, and the type of repair. Submitting Appendix 01 of the service bulletin to Airbus is acceptable for compliance with this requirement. Under the provisions of the Paperwork Reduction Act (44 U.S.C. 3501 et seq.), the Office of Management and Budget (OMB) has approved the information collection requirements contained in this AD and has assigned OMB Control Number 2120-0056.

Alternative Methods of Compliance (AMOCs)

(j)(1) The Manager, International Branch, ANM-116, Transport Airplane Directorate, FAA, has the authority to approve AMOCs for this AD, if requested in accordance with the procedures found in 14 CFR 39.19.

(2) Before using any AMOC approved in accordance with § 39.19 on any airplane to which the AMOC applies, notify the appropriate principal inspector in the FAA Flight Standards Certificate Holding District Office.

Related Information

(k) EASA's airworthiness directive 2006-0076, dated April 3, 2006, also addresses the subject of this AD.

Issued in Renton, Washington, on June 22, 2006.

Kalene C. Yanamura,

Acting Manager, Transport Airplane Directorate, Aircraft Certification Service.