Airworthiness Directives; General Electric Company (GE); CT7-2D1 Turboshaft Engines.

[Federal Register Volume 69, Number 151 (Friday, August 6, 2004)]
[Rules and Regulations]
[Pages 47763-47765]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 04-17755]


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DEPARTMENT OF TRANSPORTATION (DOT)

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2004-18758; Directorate Identifier 2004-NE-24-AD; 
Amendment 39-13763; AD 2004-16-07]
RIN 2120-AA64


Airworthiness Directives; General Electric Company (GE); CT7-2D1 
Turboshaft Engines.

AGENCY: Federal Aviation Administration (FAA), DOT.

ACTION: Final rule; request for comments.

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SUMMARY: The FAA is adopting a new airworthiness directive (AD) for GE 
CT7-2D1 turboshaft engines. This AD requires replacing certain turbine 
stage 2 aft cooling plates, part number (P/N) 6064T0P02. This AD 
results from an uncontained failure of a turbine stage 2 aft cooling 
plate in a GE CT7 turboprop engine. We are issuing this AD to prevent a 
similar uncontained failure of turbine stage 2 aft cooling plates in GE 
CT7-2D1 turboshaft engines.

DATES: This AD becomes effective August 23, 2004.
    We must receive any comments on this AD by October 5, 2004.

ADDRESSES: Use one of the following addresses to submit comments on 
this proposed AD.
    <bullet> DOT Docket Web site: Go to http://dms.dot.gov and follow 
the instructions for sending your comments electronically.
    <bullet> Government-wide rulemaking Web site: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: Docket Management Facility, U.S. Department of 
Transportation, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
    <bullet> Fax: (202) 493-2251.
    <bullet> 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 AD in the AD docket on the 
Internet at http://dms.dot.gov.

FOR FURTHER INFORMATION CONTACT: Mark J. Bouyer, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7757; fax (781) 238-7755.

SUPPLEMENTARY INFORMATION: In July of 1999, an uncontained failure of a 
turbine stage 2 aft cooling plate occurred on a GE CT7 turboprop 
engine. An investigation indicated that the electro-discharge (EDM) 
machining of the cooling airholes caused microcracks in the walls of 
the airholes that could propagate through the turbine stage 2 cooling 
plate and result in an uncontained engine failure. We issued AD 2002-
01-03 to prevent an uncontained failure of turbine stage 2 aft cooling 
plates in GE CT7 turboprop engines. In October of 2003, the 
manufacturer informed us of a similar problem with GE CT7-2D1 
turboshaft engines. This AD requires replacing turbine stage 2 aft 
cooling plates, P/N 6064T07P02, with serial numbers (SNs) GFFN****, 
GFFP****, GFFR0*** through GFFR7***, GFFR81** through GFFR89**, 
GFFR8A** through GFFR8G**, GFFR8H92 through GFFR8H99, and GFFR8H9A 
through GFFR8H9N. Asterisks represent any subsequent number or letter 
that follow the root SN. This condition, if not corrected, could result 
in an uncontained failure of turbine stage 2 aft cooling plates in GE 
CT7-2D1 turboshaft engines.

FAA's Determination and Requirements of This AD

    Although no aircraft that are registered in the United States use 
these engines, the possibility exists that the engines could be used on 
aircraft that

[[Page 47764]]

are registered in the United States in the future. The unsafe condition 
as previously described in GE CT7 turboprop engines is likely to exist 
or develop in GE CT7-2D1 turboshaft engines because they are of the 
same type design. We are issuing this AD to prevent an uncontained 
failure of turbine stage 2 aft cooling plates in GE CT7-2D1 turboshaft 
engines. This AD requires replacing turbine stage 2 aft cooling plates, 
P/N 6064T07P02, with SNs GFFN****, GFFP****, GFFR0*** through GFFR7***, 
GFFR81** through GFFR89**, GFFR8A** through GFFR8G**, GFFR8H92 through 
GFFR8H99, and GFFR8H9A through GFFR8H9N at the next disassembly of the 
gas generator turbine rotor assembly at an FAA-approved overhaul 
facility, but not to exceed 5,000 cycles-since-new.

FAA's Determination of the Effective Date

    Since there are currently no domestic operators of this engine, 
notice and opportunity for public comment before issuing this AD are 
unnecessary. A situation exists that allows the immediate adoption of 
this regulation.

Docket Management System (DMS)

    We have implemented new procedures for maintaining AD dockets 
electronically. As of May 17, 2004, we posted new AD actions on the DMS 
and assigned a DMS docket number. We track each action and assign a 
corresponding Directorate identifier. The DMS docket No. is in the form 
``Docket No. FAA-200X-XXXXX.'' Each DMS docket also lists the 
Directorate identifier (``Old Docket Number'') as a cross-reference for 
searching purposes.

Comments Invited

    This AD is a final rule that involves requirements affecting flight 
safety and was not preceded by notice and an opportunity for public 
comment; however, we invite you to submit any written relevant data, 
views, or arguments regarding this AD. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. FAA-2004-18758; 
Directorate Identifier 2004-NE-24-AD'' in the subject line of your 
comments. We specifically invite comments on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify it.
    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 AD. Using the search function of the DMS 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 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.
    We are reviewing the writing style we currently use in regulatory 
documents. We are interested in your comments on whether the style of 
this document is clear, and your suggestions to improve the clarity of 
our communications with 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 docket that contains the AD, any comments 
received, and any final disposition in person at the DMS Docket Offices 
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.

Regulatory Findings

    We have determined that this AD will not have federalism 
implications under Executive Order 13132. This AD will 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 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 summary of the costs to comply with this AD and 
placed it in the AD Docket. You may get a copy of this summary at the 
address listed under ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety.

Adoption of the Amendment

0
Under the authority delegated to me by the Administrator, the Federal 
Aviation Administration amends part 39 of the Federal Aviation 
Regulations (14 CFR part 39) as follows:

PART 39--AIRWORTHINESS DIRECTIVES

0
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]

0
2. The FAA amends Sec.  39.13 by adding the following new airworthiness 
directive:

2004-16-07. General Electric Company: Amendment 39-13763. Docket No. 
FAA-2004-18758; Directorate Identifier 2004-NE-24-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective August 
23, 2004.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CT7-2D1 
turboshaft engines with turbine stage 2 aft cooling plates, part 
number (P/N) 6064T07P02, and serial numbers (SN) starting with 
GFFN****, GFFP****, GFFR0*** through GFFR7***, GFFR81** through 
GFFR89**, GFFR8A** through GFFR8G**, GFFR8H92 through GFFR8H99, and 
GFFR8H9A through GFFR8H9N installed. Asterisks represent any 
subsequent number or letter that follow the root SN. These engines 
are installed on, but not limited to, Sikorsky S-70 helicopters.

Unsafe Condition

    (d) This AD results from an uncontained failure of a turbine 
stage 2 aft cooling plate in a GE CT7 turboprop engine. We are 
issuing this AD to prevent a similar uncontained failure of turbine 
stage 2 aft cooling plates in GE CT7-2D1 turboshaft engines.

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.

Cooling Plate Removal

    (f) At the next disassembly of the gas generator turbine rotor 
assembly at an FAA-approved overhaul facility, but not later than 
5,000 cycles-since-new, replace any turbine stage 2 aft cooling 
plate, P/N 6064T07P02, with SNs starting with GFFN****, GFFP****, 
GFFR0*** through GFFR7***, GFFR81** through GFFR89**, GFFR8A** 
through GFFR8G**, GFFR8H92 through GFFR8H99, and GFFR8H9A through 
GFFR8H9N, with a cooling plate that does not have a SN specified in 
this AD.
    (g) After the effective date of this AD, do not install stage 2 
aft cooling plate, P/N

[[Page 47765]]

6064T07P02, SNs GFFN****, GFFP****, GFFR0*** through GFFR7***, 
GFFR81** through GFFR89**, GFFR8A** through GFFR8G**, GFFR8H92 
through GFFR8H99, and GFFR8H9A through GFFR8H9N into any engine.

Material Incorporated by Reference

    (h) None.

Related Information

    (i) GE CT7-TS Alert Service Bulletin 72-A0032, dated June 11, 
2003, provides additional information regarding the disassembly of 
the gas generator turbine rotor assembly.

    Issued in Burlington, Massachusetts, on July 29, 2004.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 04-17755 Filed 8-5-04; 8:45 am]
BILLING CODE 4910-13-P

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