[Federal Register: July 5, 2005 (Volume 70, Number 127)]
[Proposed Rules]
[Page 38625-38627]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr05jy05-12]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-21719; Directorate Identifier 2005-NE-19-AD]
RIN 2120-AA64
Airworthiness Directives; Hamilton Sundstrand Power Systems
(formerly Sundstrand Power Systems) Auxiliary Power Units Models T-62T-
46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T-46C7A
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).
The new AD is for Hamilton Sundstrand Power Systems (formerly
Sundstrand Power Systems) auxiliary power units (APUs) models T-62T-
46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T-46C7A, with
compressor impeller assembly, part number (P/N) 4502020 or 4502020A,
installed. This proposed AD would require removal from service of those
compressor impeller assemblies at reduced service life limits. This
proposed AD results from two reports of uncontained failures of
compressor impeller assemblies. We are proposing this AD to prevent an
uncontained APU failure and damage to the airplane.
DATES: We must receive any comments on this proposed AD by September 6,
2005.
ADDRESSES: Use one of the following addresses to comment 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 20590-0001.
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.
You may examine the comments on this proposed AD in the AD docket
on the Internet at http://dms.dot.gov.
[[Page 38626]]
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 send us any written relevant data, views, or
arguments regarding this proposal. Send your comments to an address
listed under ADDRESSES. Include ``Docket No. FAA-2005-21719;
Directorate Identifier 2005-NE-19-AD'' in the subject line 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 the
Docket Management System (DMS) Web site, anyone can find and read the
comments in any of our dockets. The Web site includes 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 AD Docket
You may examine the docket that contains the proposal, any comments
received and, any final disposition in person at the DMS Docket Office
between 9 a.m. and 5 p.m., Monday through Friday, except Federal
holidays. The Docket Office (telephone (800) 647-5227) is located on
the plaza level of the Department of Transportation Nassif Building at
the street address stated in ADDRESSES. Comments will be available in
the AD docket shortly after the DMS receives them.
Discussion
We received two reports of uncontained failures of compressor
impeller assemblies installed in Hamilton Sundstrand Power Systems
model T-62T-46C3 APUs. One report was of a compressor impeller failing
in the field, at 17,680 cycles-since-new (CSN). The other report was of
a compressor impeller failing at the manufacturer's site. Hamilton
Sundstrand has determined that these failures were caused by low-cycle-
fatigue (LCF) cracking. The LCF cracking starts on the compressor
impeller back face radius, and grows circumferentially to failure, over
a high number of cycles. This condition, if not corrected, could result
in uncontained APU failure and damage to the airplane.
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. We are proposing this AD, which, for Hamilton
Sundstrand Power Systems model T-62T APUs with compressor impeller
assembly P/N 4502020 or 4502020A installed, would require:
For APUs with compressor impeller assemblies that have
12,000 or more CSN on the effective date of the proposed AD, removal
from service before accumulating 500 additional cycles; and
For APUs with compressor impeller assemblies that have
fewer than 12,000 CSN on the effective date of the proposed AD, removal
from service at or before accumulating 12,500 CSN.
Costs of Compliance
There are about 50 Hamilton Sundstrand Power Systems model T-62T
APUs of the affected design in the worldwide fleet. We estimate that
eight APUs installed on airplanes of U.S. registry would be affected by
this proposed AD. We also estimate that it would take about 8 work
hours to remove and install an APU, and that the average labor rate is
$65 per work hour. A new or serviceable compressor impeller assembly,
P/N 4502020 or 4502020A, may be installed provided it meets the cycles-
since-new criteria in the compliance section of this proposed AD. It
would take about 55.5 hours to remove and replace affected compressor
impeller assembly parts. New configuration replacement parts for each
APU would cost approximately $36,587. Based on these figures, we
estimate the total cost of the proposed AD to U.S. operators, to
remove, upgrade, and install the APUs to be $325,716.
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. 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 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
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:
[[Page 38627]]
Hamilton Sundstrand: Docket No. FAA-2005-21719; Directorate
Identifier 2005-NE-19-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this airworthiness directive (AD) action by September 6,
2005.
Affected ADs
(b) None.
Applicability
(c) This AD applies to Hamilton Sundstrand Power Systems
(formerly Sundstrand Power Systems) auxiliary power units (APUs)
models T-62T-46C2, T-62T-46C2A, T-62T-46C3, T-62T-46C7, and T-62T-
46C7A, with compressor impeller assembly, part number (P/N) 4502020
or 4502020A installed. These APUs are installed on, but not limited
to, BAE Systems AVRO 146, Fokker 50, Saab 2000, and Saab 340
airplanes.
Unsafe Condition
(d) This AD results from two reports of uncontained failures of
compressor impeller assemblies. We are issuing this AD to prevent an
uncontained APU failure and damage to the airplane.
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.
(f) For APUs with compressor impeller assemblies that have
12,000 or more cycles-since-new (CSN) accumulated on the effective
date of this AD, remove compressor impeller assemblies from service
before accumulating 500 additional cycles.
(g) For APUs with compressor impeller assemblies that have fewer
than 12,000 CSN on the effective date of this AD, remove compressor
impeller assemblies from service at or before accumulating 12,500
CSN.
Alternative Methods of Compliance
(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.
Related Information
(i) Hamilton Sundstrand Service Bulletins No. 4500090-49-33,
dated January 6, 2005, No. 4500482-49-33, dated January 6, 2005, No.
4501578-49-22, dated January 13, 2005, No. 4501690-49-47, dated
November 19, 2004, and No. 4501909-49-16, dated January 13, 2005,
pertain to the subject of this AD.
Issued in Burlington, Massachusetts, on June 28, 2005.
Diane S. Romanosky,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 05-13134 Filed 7-1-05; 8:45 am]
BILLING CODE 4910-13-P