[Federal Register Volume 70, Number 60 (Wednesday, March 30, 2005)]
[Proposed Rules]
[Pages 16185-16186]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 05-6254]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2005-20757; Directorate Identifier 2004-NM-192-AD]
RIN 2120-AA64


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).

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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: (202) 493-2251.
     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 (425) 
227-2125; fax (425) 227-1149.

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 (800) 647-
5227) 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

[[Page 16186]]

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 Sec.  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.


Sec.  39.13  [Amended]

    2. The FAA amends Sec.  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.
[FR Doc. 05-6254 Filed 3-29-05; 8:45 am]
BILLING CODE 4910-13-P