[Federal Register Volume 69, Number 89 (Friday, May 7, 2004)]
[Proposed Rules]
[Pages 25525-25526]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-10430]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2003-NE-61-AD]
RIN 2120-AA64


Airworthiness Directives; Hamilton Sundstrand Power Systems T-62T 
Series Auxiliary Power Units (APUs)

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to adopt a new airworthiness directive (AD) 
for Hamilton Sundstrand Power Systems Models T-62T-46C12 and T-62T-
40C14 (APS 500R) APUs with fuel filter housing assembly, part numbers 
(P/Ns) 4951627, 4951960, or 4952039, installed. This proposed AD would 
require installation of a bracket to prevent a failed bypass button 
from protruding beyond the internal o-ring seal. This proposed AD 
results from reports of leaks caused by cracked bypass buttons that 
protruded beyond the o-ring seal. We are proposing this AD to prevent a 
fire or explosion caused by a fuel leak from a failed bypass button on 
the fuel filter housing.

DATES: We must receive any comments on this proposed AD by July 6, 
2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD:
     By mail: Federal Aviation Administration (FAA), New 
England Region, Office of the Regional Counsel, Attention: Rules Docket 
No. 2003-NE-61-AD, 12 New England Executive Park, Burlington, MA 01803-
5299.
     By fax: (781) 238-7055.
     By e-mail: [email protected].
    You can get the service information identified in this proposed AD 
from Hamilton Sundstrand Technical Publications Department, P.O. Box 
7002, Rockford, IL 61125-7002, U.S.A.
    You may examine the AD docket at the FAA, New England Region, 
Office of the Regional Counsel, 12 New England Executive Park, 
Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Roger Pesuit, Aerospace Engineer, Los 
Angeles Aircraft Certification Office, FAA, Transport Airplane 
Directorate, 3960 Paramount Blvd., Lakewood, CA 90712-4137; telephone 
(562) 627-5251, fax (562) 627-5210.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to submit any written relevant data, views, or 
arguments regarding this proposal. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. 2003-NE-61-AD'' in the 
subject line of your comments. If you want us to acknowledge receipt of 
your mailed comments, send us a self-addressed, stamped postcard with 
the docket number written on it; we will date-stamp your postcard and 
mail it back to you. We specifically invite comments on the overall 
regulatory, economic, environmental, and energy aspects of the proposed 
AD. If a person contacts us verbally, and that contact relates to a 
substantive part of this proposed AD, we will summarize the contact and 
place the summary in the docket. We will consider all comments received 
by the closing date and may amend the proposed AD in light of those 
comments.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on

[[Page 25526]]

whether the style of this document is clear, and your suggestions to 
improve the clarity of our communications that affect you. You can get 
more information about plain language at http://www.faa.gov/language 
and http://www.plainlanguage.gov.

Examining the AD Docket

    You may examine the AD Docket (including any comments and service 
information), by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. See ADDRESSES for the 
location.

Discussion

    On October 22, 2003, Hamilton Sundstrand Power Systems advised us 
that they received reports of five fuel filter housing assemblies on 
which the bypass buttons failed. Fuel filter housing assemblies, P/Ns 
4951627, 4951960, and 4952039, have bypass buttons that can fail from 
fatigue cracks. When the bypass button cracks through, the indicating 
portion of the button can extend beyond the internal o-ring seal and 
can allow fuel to leak into the APU compartment. This condition, if not 
corrected, could result in a fire or explosion caused by a fuel leak 
from a failed bypass button on the fuel filter.

Relevant Service Information

    We have reviewed and approved the technical contents of Hamilton 
Sundstrand Power Systems Alert Service Bulletin (ASB) No. ASB-4504112-
49-22, dated December 2, 2003; and ASB No. ASB-4503067-49-9, dated 
December 2, 2003, that describe procedures for installing brackets on 
the fuel filter.

FAA's Determination and Requirements of the Proposed AD

    We have evaluated all pertinent information and identified an 
unsafe condition that is likely to exist or develop on other products 
of this same type design. Therefore, we are proposing this AD, which 
would require installing a bracket to prevent a failed bypass button 
from protruding beyond the internal o-ring seal.

Interim Action

    These actions are interim actions and we may take further 
rulemaking actions in the future.

Costs of Compliance

    There are about 552 Hamilton Sundstrand APUs of the affected design 
in the worldwide fleet. We estimate that 448 APUs installed on 
airplanes of U.S. registry would be affected by this proposed AD. We 
also estimate that it would take about 1 work hour per APU to perform 
the proposed actions, and that the average labor rate is $65 per work 
hour. Required parts would cost about $517 per APU. The manufacturer 
indicated that they might provide the parts at no cost. Based on these 
figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $260,736.

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. Would 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 summary of the costs to comply with this proposal and 
placed it in the AD Docket. You may get a copy of this summary by 
sending a request to us at the address listed under ADDRESSES. Include 
``AD Docket No. 2003-NE-61-AD'' in your request.

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 Federal Aviation Administration 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:

Hamilton Sundstrand Power Systems: Docket No. 2003-NE-61-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by July 6, 
2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to Hamilton Sundstrand Power Systems Models 
T-62T-46C12 and T-62T-40C14 (APS 500R) auxiliary power units (APUs) 
with fuel filter housing assemblies, part numbers (P/Ns) 4951627, 
4951960, or 4952039, installed. These APUs are installed on, but not 
limited to, Bombardier DHC-8-400 airplanes and Empresa Brasileira de 
Aeronautica S.A. (Embraer) EMB-135 and -145 series airplanes.

Unsafe Condition

    (d) This AD results from reports of leaks caused by cracked 
bypass buttons that protruded beyond the o-ring seal. We are issuing 
this AD to prevent a fire or explosion caused by a fuel leak from a 
failed bypass button on the fuel filter.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed within 400 hours time-in-service or 6 months after the 
effective date of this AD, whichever occurs earlier, unless the 
actions have already been done.

Installation of Bracket on APU Model T-62T-46C12

    (f) Install a bracket onto the fuel filter housing assembly on 
APU Model T-62T-46C12. Use 2.A through 2.D. of the Accomplishment 
Instructions of Hamilton Sundstrand Alert Service Bulletin (ASB) No. 
ASB-4503067-49-9, dated December 2, 2003, to install the bracket.

Installation of Bracket on APU Model T-62T-40C14 (APS 500R)

    (g) Install a bracket onto the fuel filter housing assembly on 
APU Model T-62T-40C14 (APS 500R). Use 2.A through 2.D. of the 
Accomplishment Instructions of Hamilton Sundstrand ASB No. ASB-
4504112-49-22, dated December 2, 2003, to install the bracket.

Alternative Methods of Compliance (AMOCs)

    (h) The Manager, Los Angeles Aircraft Certification Office, has 
the authority to approve alternative methods of compliance for this 
AD if requested using the procedures found in 14 CFR 39.19.

Material Incorporated by Reference

    (i) None.

Related Information

    (j) None.


    Issued in Burlington, Massachusetts, on May 3, 2004.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 04-10430 Filed 5-6-04; 8:45 am]
BILLING CODE 4910-13-P