E6-7481. Airworthiness Directives; Airbus Model A300 Airplanes; Model A310 Airplanes; and 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 airplanes and Model A310 airplanes and for certain Airbus Model A300-600 series airplanes. This proposed AD would require an inspection of the wing and center fuel tanks to determine if certain P-clips are installed and corrective action if necessary. This proposed AD also would require an inspection of electrical bonding points of certain equipment in the center fuel tank for the presence of a blue coat and related investigative and corrective actions if necessary. This proposed AD also would require installation of new bonding leads and electrical bonding points on certain equipment in the wing, center, and trim fuel tanks, as necessary. This proposed AD results from fuel system reviews conducted by the manufacturer. We are proposing this AD to ensure continuous electrical bonding protection of equipment in the wing, center, and trim fuel tanks and to prevent damage to wiring in the wing and center fuel tanks, due to failed P-clips used for retaining the wiring and pipes, which could result in a possible fuel ignition source in the fuel tanks.

DATES:

We must receive comments on this proposed AD by June 16, 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, Transport Airplane Directorate, FAA, 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 in the ADDRESSES section. Include the docket number “FAA-2006-24779; Directorate Identifier 2006-NM-044-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” (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 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 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 A300 airplanes and A310 airplanes and on certain 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 DGAC advises that the inserts on NSA5516-XXND and NSA5516-XXNJ type P-clips, which are used to retain wiring and pipes in wing and center fuel tanks, may swell and soften when immersed in fuel or fuel vapor. Investigation revealed that failed P-clips could chafe through the insulation of the wiring. Damage to wiring in the wing and center fuel tanks, if not corrected, could result in a possible fuel ignition source in the fuel tanks.

The DGAC advises that, as a result of fuel system reviews conducted by the manufacturer, continuous electrical bonding protection of equipment in the wing, center, and trim fuel tanks, as applicable, is also necessary to ensure that the unsafe condition of this AD is addressed.

Relevant Service Information

Airbus has issued the following service bulletins:

Airbus—	Airbus service bulletin—	Dated—
Model A300 airplanes	A300-28-0079 A300-28-0081	September 29, 2005. July 20, 2005.
Model A310 airplanes	A310-28-2142 A310-28-2143 A310-28-2153	August 26, 2005. July 20, 2005. July 20, 2005.
Model A300-600 series airplanes	A300-28-6064 A300-28-6068 A300-28-6077	July 28, 2005. July 20, 2005. July 25, 2005.

Service Bulletins A300-28-0081, A300-28-6068, and A310-28-2143 describe procedures for inspecting the left and right wing fuel tanks and center fuel tank to determine if any NSA5516-XXND and NSA5516-XXNJ type P-clips are installed for retaining wiring and pipes in any tank and corrective action if necessary. The corrective action is to replace any NSA5516-XXND and NSA5516-XXNJ type P-clips with NSA5516-XXNF type P-clips.

Service Bulletins A300-28-0079, A300-28-6064, and A310-28-2142 describe procedures for checking the electrical bonding points of certain equipment in the center fuel tank for the presence of a blue coat and doing related investigative and corrective actions if necessary. The related investigative action is to measure the electrical resistance between the equipment and structure, if a blue coat is not present. The corrective action is to electrically bond the equipment, if the measured resistance is greater than 10 milliohms. Service Bulletins A300-28-0079, A300-28-6064, and A310-28-2142 also describe procedures for installing new bonding leads and electrical bonding points on certain equipment in the left and right wing fuel tanks and center fuel tank.

Service Bulletin A310-28-2153 describes procedures for installing new bonding lead(s) on the water drain system of the trim fuel tank and installing electrical bonding points on the ventilation intake system, vent float valves, ventilation system at numerous positions, water drain valve, water drain system, adapter-bulkhead, indicator-magnetic level, and scavenger fuel pump of the trim fuel tank.

Service Bulletin A300-28-6077 describes procedures for installing new bonding lead(s) on the water drain system of the trim fuel tank and installing electrical bonding points on the ventilation intake system, vent float valves, ventilation system at numerous positions, water drain valve, water drain system, adapter-bulkhead, and indicator-magnetic level of the trim fuel tank, for configuration 01 and 02 airplanes. Service Bulletin A300-28-6077 also describes procedures for installing electrical bonding points on the scavenger fuel pump of the trim fuel tank on configuration 03 airplanes and installing electrical bonding on the ventilation intake system of the trim fuel tank on configuration 04 airplanes.

Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The DGAC mandated the service information and issued airworthiness directive F-2006-031, dated February 1, 2006, 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 § 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 French Airworthiness Directive.”

Differences Between the Proposed AD and French Airworthiness Directive

The applicability of French airworthiness directive F-2006-031 excludes A300 airplanes on which Airbus Service Bulletins A300-28-0079 and A300-28-0081 were accomplished in service. French airworthiness directive F-2006-031 also excludes A310 airplanes on which Airbus Service Bulletins A310-28-2142 and A310-28-2143 were accomplished in service and, for airplanes equipped with trim fuel tanks, on which Airbus Service Bulletin A310-28-2153 was accomplished 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 those service bulletins, as applicable. This requirement would ensure that the actions specified in the service bulletins 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. These differences have been coordinated with the DGAC.

The applicability of French airworthiness directive F-2006-031 excludes A300-600 airplanes not equipped with trim fuel tanks that have received Airbus Modifications 12308 and 12495 in production. French airworthiness directive F-2006-031 also excludes A300-600 airplanes equipped with trim fuel tanks that have received Airbus Modifications 12308, 12495, 12294, and 12476 in production. However, the DGAC has informed us that the applicability of French airworthiness directive F-2006-031 should have excluded A300-600 airplanes not equipped with trim fuel tanks on which Airbus Modifications 12226, 12365, and 12308 have been incorporated in production and A300-600 airplanes equipped with trim fuel tanks on which Airbus Modifications 12226, 12365, 12308, 12294, and 12476 have been incorporated in production; therefore, we have excluded these airplanes in the applicability of this proposed AD.

Clarification of Inspection Terminology

The “inspection” specified in Service Bulletins A300-28-0081, A300-28-6068, and A310-28-2143 and the “check” specified in Service Bulletins A300-28-0079, A300-28-6064, and A310-28-2142 are referred to as a “general visual inspection” in this proposed AD. We have included the definition for a detailed inspection in a note in this proposed AD.

Costs of Compliance

There are about 29 Model A300 airplanes, 63 Model 310 airplanes, and 102 Model A300-600 series airplanes of the affected design in the worldwide fleet. The following table provides the estimated costs, at an average labor rate of $80 per hour, for U.S. operators to comply with this proposed AD. For some actions, the estimated work hours and cost of parts in the following table depend on the airplane configuration.

Estimated Costs

Model	Action	Work hours	Parts	Cost per airplane	Number of U.S.- registered airplanes	Fleet cost
A300 airplanes	Inspect wing and center fuel tanks for P-clips	40	None	$3,200	29	$92,800
	Install bonding leads/points in wing and center fuel tank	136-155	$3,800-$5,200	$14,680-$17,600	29	$425,720-$510,400
A310 airplanes	Inspect wing and center fuel tanks for P-clips	40	None	$3,200	63	$201,600
	Install bonding leads/points in wing and center fuel tank	248-285	$8,840-$9,190	$28,680-$31,990	63	$1,806,840-$2,015,370
	Inspect and install bonding leads/points in the trim fuel tank	53-61	$50-$70	$4,290-$4,950	63	$270,270-$311,850
A300-600 series airplanes	Inspect wing and center fuel tanks for P-clips Install bonding leads/points in wing and center fuel tank	40   157-185	None   $8,840-$9,190	$3,200   $21,400-$23,990	102   102	$326,400   $2,182,800-$2,446,980
	Inspect and install bonding leads/points in the trim fuel tank	2-61	$50-$70	$210-$4,950	102	$21,420-$504,900

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-2006-24779; Directorate Identifier 2006-NM-044-AD.

Comments Due Date

(a) The FAA must receive comments on this AD action by June 16, 2006.

Affected ADs

(b) None.

Applicability

(c) This AD applies to the Airbus airplanes identified in paragraphs (c)(1) and (c)(2) of this AD, certificated in any category.

(1) All Model A300 airplanes and Model A310 airplanes.

(2) Model A300 B4-601, B4-603, B4-620, and B4-622 airplanes; Model A300 B4-605R and B4-622R airplanes; Model A300 F4-605R and F4-622R airplanes; and Model A300 C4-605R Variant F airplanes; except those airplanes identified in paragraphs (c)(2)(i) and (c)(2)(ii) of this AD.

(i) Airplanes not equipped with trim fuel tanks on which Airbus Modifications 12226, 12365, and 12308 have been incorporated in production.

(ii) Airplanes equipped with trim fuel tanks on which Airbus Modifications 12226, 12365, 12308, 12294, and 12476 have been incorporated in production.

Unsafe Condition

(d) This AD results from fuel system reviews conducted by the manufacturer. We are issuing this AD to ensure continuous electrical bonding protection of equipment in the wing, center, and trim fuel tanks and to prevent damage to wiring in the wing and center fuel tanks, due to failed P-clips used for retaining the wiring and pipes, which could result in a possible fuel ignition source in the fuel tanks.

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 References

(f) The term “service bulletin,” as used in this AD, means the Accomplishment Instructions of the service bulletin identified in Table 1 of this AD, as applicable.

Table 1.—Service Bulletin References

For Airbus—	And the actions specified in—	Airbus service bulletin—	Dated—
Model A300 airplanes	paragraph (g) of this AD	A300-28-0081	July 20, 2005.
	paragraph (h) of this AD	A300-28-0079	September 29, 2005.
Model A310 airplanes	paragraph (g) of this AD	A310-28-2143	July 20, 2005.
	paragraph (h) of this AD	A310-28-2142	August 26, 2005.
	paragraph (i) of this AD	A310-28-2153	July 20, 2005.
Model A300 B4-601, B4-603, B4-620, and B4-622 airplanes; Model A300 B4-605R and B4-622R airplanes; Model A300 F4-605R and F4-622R airplanes; and Model A300 C4-605R Variant F airplanes	paragraph (g) of this AD	A300-28-6068	July 20, 2005.
	paragraph (h) of this AD	A300-28-6064	July 28, 2005.
	paragraph (i) of this AD	A300-28-6077	July 25, 2005.

Inspection and Corrective Actions

(g) Within 59 months after the effective date of this AD: Do a general visual inspection of the right and left wing fuel tanks and center fuel tank, if applicable, to determine if any NSA5516-XXND and NSA5516-XXNJ type P-clips are installed for retaining wiring and pipes in any tank, and do all applicable corrective actions before further flight after the inspection, by accomplishing all the actions specified in the service bulletin.

Note 1:

For the purposes of this AD, a general visual inspection is: “A visual examination of an interior or exterior area, installation, or assembly to detect obvious damage, failure, or irregularity. This level of inspection is made from within touching distance unless otherwise specified. A mirror may be necessary to ensure visual access to all surfaces in the inspection area. This level of inspection is made under normally available lighting conditions such as daylight, hangar lighting, flashlight, or droplight and may require removal or opening of access panels or doors. Stands, ladders, or platforms may be required to gain proximity to the area being checked.”

Installation of Bonding Leads and Points for Wing and Center Fuel Tanks

(h) Within 59 months after the effective date of this AD: Do the actions specified in paragraphs (h)(1) and (h)(2) of this AD, by accomplishing all the actions specified in the service bulletin.

(1) In the center fuel tank, if applicable, do a general visual inspection of the electrical bonding points of the equipment identified in the service bulletin for the presence of a blue coat, and do all related investigative and corrective actions before further flight after the inspection.

(2) In the left and right wing fuel tanks and center fuel tank, if applicable, install bonding leads and electrical bonding points on the equipment identified in the service bulletin.

Installation of Bonding Leads and Points for the Trim Fuel Tank

(i) For Model A310 airplanes; Model A300 B4-601, B4-603, B4-620, and B4-622 airplanes; Model A300 B4-605R and B4-622R airplanes; Model A300 F4-605R and F4-622R airplanes; and Model A300 C4-605R Variant F airplanes; equipped with a trim fuel tank: Within 59 months after the effective date of this AD, install a new bonding lead(s) on the water drain system of the trim fuel tank and install electrical bonding points on the equipment identified in the service bulletin in the trim fuel tank, by accomplishing all the actions specified in the service bulletin, as applicable.

Parts Installation

(j) As of the effective date of this AD, no person may install any NSA5516-XXND or NSA5516-XXNJ type P-clip for retaining wiring and pipes in any wing, center, or trim fuel tank, on any airplane.

Alternative Methods of Compliance (AMOCs)

(k)(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

(l) French airworthiness directive F-2006-031, dated February 1, 2006, also addresses the subject of this AD.

Issued in Renton, Washington, on May 8, 2006.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.