05-6254. Airworthiness Directives; BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ 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 BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ series airplanes. This proposed AD would require modifying the auxiliary power unit (APU) exhaust duct in the environmental control system (ECS) bay; installing new, improved insulation on this APU exhaust duct; and replacing the existing drain pipe with a new exhaust drain pipe blank. This proposed AD is prompted by a determination that the temperature of the skin of the APU exhaust duct in the ECS bay is higher than the certificated maximum temperature for this area. We are proposing this AD to prevent the potential for ignition of fuel or hydraulic fluid, which could leak from pipes running through the ECS bay. Ignition of these flammable fluids could result in a fire in the ECS bay.

DATES:

We must receive comments on this proposed AD by April 29, 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 British Aerospace Regional Aircraft American Support, 13850 Mclearen Road, Herndon, Virginia 20171.

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-2005-20757; the directorate identifier for this docket is 2004-NM-192-AD.

FOR FURTHER INFORMATION CONTACT:

Dan Rodina, 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-2005-20757; Directorate Identifier 2004-NM-192-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 Civil Aviation Authority (CAA), which is the airworthiness authority for the United Kingdom, notified us that an unsafe condition may exist on certain BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ series airplanes. The CAA advises that it has determined that the temperature of the skin of the auxiliary power unit (APU) exhaust duct in the environmental control system (ECS) bay is higher than the certificated maximum temperature for this area. The ECS bay is not a designated fire zone; therefore, there is no fire detection or suppression system. Also, ventilation airflow around the APU exhaust duct is low. Pipes carrying fuel and hydraulic fluid run through the ECS bay. Should these pipes leak flammable fluids, the excessive temperature of the APU exhaust duct skin could present an ignition source. This condition, if not corrected, could result in a fire in the ECS bay.

Relevant Service Information

BAE Systems (Operations) Limited has issued Modification Service Bulletin SB.49-072-36244A, dated October 11, 2004. The service bulletin describes procedures for modifying the APU exhaust duct in the ECS bay; installing new, improved insulation on the APU exhaust duct in the ECS bay; and replacing the existing drain pipe with a new exhaust drain pipe blank. Accomplishing the actions specified in the service information is intended to adequately address the unsafe condition. The CAA mandated the service information and issued British airworthiness directive G-2004-0031, dated December 22, 2004, to ensure the continued airworthiness of these airplanes in the United Kingdom.

FAA's Determination and Requirements of the Proposed AD

These airplane models are manufactured in the United Kingdom 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 CAA has kept the FAA informed of the situation described above. We have examined the CAA'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 Service Information.”

Difference Between the Proposed AD and Service Information

Although the Accomplishment Instructions in the service information provide for submitting certain information to the manufacturer, this proposed AD would not require this action.

Costs of Compliance

This proposed AD would affect about 65 airplanes of U.S. registry. The proposed actions would take about 1 work hour per airplane, at an average labor rate of $65 per work hour. Required parts would cost about $3,766 per airplane. Based on these figures, the estimated cost of the proposed AD for U.S. operators is $249,015, or $3,831 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):

BAE Systems (Operations) Limited (Formerly British Aerospace Regional Aircraft): Docket No. FAA-2005-20757; Directorate Identifier 2004-NM-192-AD.

Comments Due Date

(a) The Federal Aviation Administration must receive comments on this AD action by April 29, 2005.

Affected ADs

(b) None.

Applicability

(c) This AD applies to BAE Systems (Operations) Limited Model BAe 146 and Avro 146-RJ series airplanes, certificated in any category, on which BAE Systems Modification HCM30373A, or BAE Systems Modification HCM30373A and HCM36166C, are installed.

Unsafe Condition

(d) This AD was prompted by a determination that the temperature of the skin of the auxiliary power unit (APU) exhaust duct in the environmental control system (ECS) bay is higher than the certificated maximum temperature for this area. We are issuing this AD to prevent the potential for ignition of fuel or hydraulic fluid, which could leak from pipes running through the ECS bay. Ignition of these flammable fluids could result in a fire in the ECS bay.

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.

Modification

(f) Within 6 months after the effective date of this AD: Modify the APU exhaust duct in the ECS bay; install new, improved insulation on this APU exhaust duct; and replace the existing drain pipe with a new exhaust drain pipe blank; by doing all of the actions in the Accomplishment Instructions of BAE Systems (Operations) Limited Modification Service Bulletin SB.49-072-36244A, dated October 11, 2004. Where the Accomplishment Instructions of the service bulletin specify submitting an Advice Note to the manufacturer, this AD does not require that action.

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) British airworthiness directive G-2004-0031, dated December 22, 2004, also addresses the subject of this AD.

Issued in Renton, Washington, on March 22, 2005.

Ali Bahrami,

Manager, Transport Airplane Directorate, Aircraft Certification Service.