05-9472. Airworthiness Directives; Airbus Model A318, A319, A320, and A321 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 certain Airbus Model A318, A319, A320, and A321 series airplanes. This proposed AD would require modification of the electrical bonding of all structures and systems installed inside the center fuel tank. This proposed AD is prompted by results of fuel system reviews conducted by the manufacturer. We are proposing this AD to prevent electrical arcing in the center fuel tank due to inadequate bonding, which could result in an explosion of the center fuel tank and consequent loss of the airplane.

DATES:

We must receive comments on this proposed AD by June 13, 2005.

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.
• By 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.

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

You can examine the contents of this AD docket on the Internet at http://dms.dot.gov,, or in person at the Docket Management Facility, U.S. Department of Transportation, 400 Seventh Street SW., room PL-401, on the plaza level of the Nassif Building, Washington, DC. This docket number is FAA-2005-21189; the directorate identifier for this docket is 2005-NM-055-AD.

FOR FURTHER INFORMATION CONTACT:

Tim Dulin, Aerospace Engineer, International Branch, ANM-116, FAA, Transport Airplane Directorate, 1601 Lind Avenue, SW., Renton, Washington 98055-4056; 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 under ADDRESSES. Include “Docket No. FAA-2005-21189; Directorate Identifier 2005-NM-055-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 submitted 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 our docket 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 can review the DOT's complete Privacy Act Statement in the Federal Register published on April 11, 2000 (65 FR 19477-78), or you can visit http://dms.dot.gov.

Examining the Docket

You can 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 DMS receives them.

Discussion

The FAA has examined the underlying safety issues involved in recent 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' (67 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 another 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 cooperate 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 proposed 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 Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified us that an unsafe condition may exist on certain Airbus Model A318, A319, A320, and A321 series airplanes. The DGAC advises that a design review showed that the electrical bonding in the center fuel tank of the affected airplanes should be modified. The modification would reduce the possibility of an electrical discharge in the fuel tank. An electrical discharge could result in an explosion of the center fuel tank and consequent loss of the airplane.

Relevant Service Information

Airbus has issued Airbus Service Bulletin A320-28-1104, Revision 01, dated December 8, 2004. The service bulletin describes procedures for modifying the electrical bonding of all structures and systems installed inside the center fuel tank of the affected airplanes. The modification consists of checking certain existing bonding points for the presence of blue coat and installing new bonding points. If blue coat is present at the bonding point, the service bulletin recommends no further action. If blue coat is not present, the service bulletin recommends measuring the electrical (ohmic) resistance between the part and the structure. If the ohmic resistance is less than 10 milliohms, the service bulletin recommends no further action. If the ohmic resistance is 10 milliohms or more, the service bulletin recommends installing the bonding.

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-2005-028, dated February 16, 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 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 “Difference Between the Proposed AD and the French Airworthiness Directive.”

Difference Between the Proposed AD and the French Airworthiness Directive

The applicability of French airworthiness directive F-2005-028 excludes airplanes that accomplished Airbus Service Bulletin A320-28-1104 in service. However, we have not excluded those airplanes in the applicability of this proposed AD; rather, this proposed AD includes a requirement to accomplish the actions specified in that service bulletin. This requirement would ensure that the actions specified in the service bulletin and required by this proposed AD are accomplished on all affected airplanes. Operators must continue to operate the airplane in the configuration required by this proposed AD unless an alternative method of compliance is approved. This difference has been coordinated with the DGAC.

Clarification of Inspection Language

The service bulletin specifies that operators should “check” for the presence of blue coat. In this proposed AD we refer to this action as a “general visual inspection.” Note 1 of this proposed AD defines this inspection.

Costs of Compliance

This proposed AD would affect about 506 airplanes of U.S. registry. The proposed actions would take between 49 and 64 work hours per airplane depending on the airplane's configuration. The average labor rate is $65 per work hour. Required parts would cost between $10 and $370 per airplane, depending on the airplane's configuration. Based on these figures, the estimated cost of the proposed AD for U.S. operators is between $1,616,670 and $2,292,180, or between $3,195 and $4,530 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. 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 FAA amends § 39.13 by adding the following new airworthiness directive (AD):

Airbus: Docket No. FAA-2005-21189; Directorate Identifier 2005-NM-055-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by June 13, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Airbus Model A318, A319, A320, and A321 series airplanes; certificated in any category; except airplanes that have received Airbus Modification 31892 in production.

Unsafe Condition

(d) This AD was prompted by results of fuel system reviews conducted by the manufacturer. We are issuing this AD to prevent electrical arcing in the center fuel tank due to inadequate bonding, which could result in an explosion of the center fuel tank 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.

Inspection and Related Investigative and Corrective Actions

(f) Within 58 months after the effective date of this AD: Modify the electrical bonding of all structures and systems installed inside the center fuel tank by accomplishing all of the actions in accordance with the Accomplishment Instructions of Airbus Service Bulletin A320-28-1104, Revision 01, dated December 8, 2004.

Actions Accomplished According to Previous Issue of Service Bulletin

(g) Actions done before the effective date of this AD in accordance with Airbus Service Bulletin A320-28-1104, dated December 2, 2003, are acceptable for compliance with the corresponding requirements of paragraph (f) of this AD.

Alternative Methods of Compliance (AMOCs)

(h) The Manager, 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.

Related Information

(i) French airworthiness directive F-2005-028, dated February 16, 2005, also addresses the subject of this AD.

Issued in Renton, Washington, on May 5, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.