05-1725. Airworthiness Directives; Airbus Model 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 A319, A320, and A321 series airplanes. This proposed AD would require replacing the cargo ventilation extraction duct at frame 65 with a new duct, and relocating the temperature sensor in the aft cargo compartment. This proposed AD is prompted by a report indicating that, during a test of the fire extinguishing system, air leakage around the temperature sensor for the aft cargo compartment reduced the concentration of fire extinguishing agent to below the level required to suppress a fire. We are proposing this AD to prevent air leakage around the temperature sensor for the aft cargo compartment, which, in the event of a fire in the aft cargo compartment, could result in an insufficient concentration of fire extinguishing agent, and consequent inability of the fire extinguishing system to suppress the fire.

DATES:

We must receive comments on this proposed AD by March 2, 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-2005-20166; the directorate identifier for this docket is 2004-NM-175-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-2005-20166; Directorate Identifier 2004-NM-175-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 Direction Générale de l'Aviation Civile (DGAC), which is the airworthiness authority for France, notified the FAA that an unsafe condition may exist on certain Airbus Model A319, A320, and A321 series airplanes. The DGAC advises that a test of the fire containment capability of the aft cargo compartment was performed on a Model A319 series airplane. The test revealed that the concentration of the halon fire extinguishing agent decreased below the level required to suppress a fire. Investigation revealed that the drop in the concentration of halon was due to too high a rate of air renewal in the compartment. Further investigation revealed that air leakage around the water drain valves in the forward and aft cargo doors and around the aft cargo compartment temperature sensor contributed to the reduced concentration of halon. The air leakage allowed the halon to leak out of the compartment, and the remaining concentration of halon was insufficient to suppress a fire. The DGAC states that a separate French airworthiness directive will address air leakage around the water drain valves. In the event of a fire in the aft cargo compartment, an insufficient concentration of fire extinguishing agent could result in the inability of the fire extinguishing system to suppress the fire.

The aft cargo compartment temperature sensor installation on the Airbus A320 and A321 series airplanes is similar to that of the Airbus A319 series airplanes; therefore, those airplanes may also be subject to this unsafe condition.

Relevant Service Information

Airbus has issued Service Bulletin A320-21-1141, dated April 7, 2004. The service bulletin describes procedures for relocating the temperature sensor in the aft cargo compartment. The procedures include replacing the duct at frame 65 with a new duct that can accommodate the temperature sensor and installing a placard, rerouting the sensor line, and installing the temperature sensor and associated hardware in the new duct. 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-2004-123, dated July 21, 2004, 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. According 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 French Airworthiness Directive.”

Difference Between the Proposed AD and French Airworthiness Directive

The applicability of French airworthiness directive F-2004-123 excludes airplanes that accomplished Airbus Service Bulletin A320-21-1141 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.

Costs of Compliance

The following table provides the estimated costs for U.S. operators to comply with this proposed AD.

Estimated Costs

Action	Work hours	Average labor rate per hour	Parts	Cost per airplane	Number of U.S.-registered airplanes	Fleet cost
Replacement of duct/relocation of temperature sensor in aft cargo compartment	34	$65	Between $7,000 and $11,640	Between $9,210 and $13,850	643	Between $5,922,030 and $8,905,550.

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-2005-20166; Directorate Identifier 2004-NM-175-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by March 2, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to Airbus Model A319, A320, and A321 series airplanes, certificated in any category; as identified in Table 1 of this AD.

Table 1.—Applicability

Airbus Model-	Having the following Airbus modification installed in production-	Or the following Airbus service bulletin incorporated in service-	But not having the following Airbus modification installed in production-
A319 series airplanes	24486	A320-21-1140	32616
A320 series airplanes	20084	A320-21-1048	32616
A321 series airplanes	22596	Not applicable	32616

Unsafe Condition

(d) This AD was prompted by a report that, during a test of the fire extinguishing system, air leakage around the temperature sensor for the aft cargo compartment reduced the concentration of fire extinguishing agent to below the level required to suppress a fire. We are issuing this AD to prevent air leakage around the temperature sensor for the aft cargo compartment, which, in the event of a fire in the aft cargo compartment, could result in an insufficient concentration of fire extinguishing agent, and consequent inability of the fire extinguishing system to suppress the fire.

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.

Relocation of Aft Cargo Compartment Temperature Sensor

(f) Within 24 months after the effective date of this AD: Replace the ventilation extraction duct with a new duct and relocate the aft cargo compartment temperature sensor by accomplishing all of the actions specified in the Accomplishment Instructions of Airbus Service Bulletin A320-21-1141, dated April 7, 2004.

Alternative Methods of Compliance (AMOCs)

(g) 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.

Related Information

(h) French airworthiness directive F-2004-123, dated July 21, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on January 18, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.