[Federal Register: April 15, 2005 (Volume 70, Number 72)]
[Proposed Rules]
[Page 19893-19894]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr15ap05-9]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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[[Page 19893]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. FAA-2005-20944; Directorate Identifier 2003-NE-64-AD]
RIN 2120-AA64
Airworthiness Directives; General Electric Company CT7-5, -7, and
-9 Series Turboprop Engines
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 General Electric Company (GE) CT7-5A2, -5A3, -7A, -7A1, -9B, -9B1,
and -9B2 turboprop engines, with stage 2 turbine aft cooling plate,
part number (P/N) 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01
installed. This proposed AD would require a onetime eddy current
inspection (ECI) of certain P/N stage 2 turbine aft cooling plate
boltholes. This proposed AD results from reports of six stage 2 turbine
aft cooling plates found cracked during inspection. We are proposing
this AD to prevent stage 2 aft cooling plate separation, resulting in
uncontained engine failure and damage to the airplane.
DATES: We must receive any comments on this proposed AD by June 14,
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 20590-001.
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.
Contact General Electric Aircraft Engines CT7 Series Turboprop
Engines, 1000 Western Ave., Lynn, MA 01910; telephone (781) 594-3140,
fax (781) 594-4805, for the service information identified in this
proposed AD.
You may examine the comments on this proposed AD in the AD docket
on the Internet at http://dms.dot.gov.
FOR FURTHER INFORMATION CONTACT: Eugene Triozzi, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7148; fax (781) 238-7199.
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 ``Docket No. FAA-2005-20944;
Directorate Identifier 2003-NE-64-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
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.
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 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.
Discussion
GE advises that they received reports of six stage 2 turbine aft
cooling plates found cracked at the boltholes. The cracks ran into the
lower ligament. Investigation has revealed that these cracks resulted
from using worn balance arbor washers and or worn nuts. The worn arbor
washers and worn nuts caused bolthole deformation and cracking. This
cracking could lead to separation of the stage 2 turbine aft cooling
plate from the engine. GE has analyzed the inspection data from 236
stage 2 turbine aft cooling plates to establish validated lives for
lower ligament cracking and breakthrough. GE has also conducted
analysis to predict lives for top ligament cracking and breakthrough,
which would lead to cooling plate separation. GE's risk analysis shows
that a onetime ECI at the next shop visit, but before accumulating an
additional 6,000 cycles-in-service (CIS) after the effective date of
the AD, of the affected P/N stage 2 turbine aft cooling plates will
provide early detection of at-risk parts. GE advises that the
production and overhaul tools have been removed and inspected to
identify and replace arbor washers and nuts that are worn. This
condition, if not corrected, could result in stage 2 aft cooling plate
separation, resulting in uncontained engine failure and damage to the
airplane.
Relevant Service Information
We have reviewed and approved the technical contents of GE Alert
Service Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 2, dated May
9, 2003, that describes procedures for performing a onetime ECI of
stage 2 turbine aft cooling plates, P/Ns 6064T07P01, 6064T07P02,
6064T07P05, and
[[Page 19894]]
6068T36P01, at the next engine or hot section module shop visit.
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 would require
a onetime ECI of the boltholes of stage 2 turbine aft cooling plates,
P/Ns 6064T07P01, 6064T07P02, 6064T07P05, and 6068T36P01. The ECI must
be done at the next engine or hot section module shop visit or before
accumulating an additional 6,000 CIS after the effective date of the
AD, whichever occurs first. The proposed AD would require you to use
the service information described previously to perform these actions.
Costs of Compliance
There are about 1,240 GE CT7-5, -7, and -9 series turboprop engines
of the affected design in the worldwide fleet. We estimate that 550
engines installed on airplanes of U.S. registry would be affected by
this proposed AD. We also estimate that it would take about one work
hour per engine to perform the proposed actions, and that the average
labor rate is $65 per work hour. We estimate that 2.5% (or 14) of the
550 engines will require stage 2 turbine aft cooling plates being
rejected by the onetime ECI. Required parts would cost about $17,000
per engine. Based on these figures, we estimate the total cost of the
proposed AD to U.S. operators to be $270,700.
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 summary of the costs to comply with this proposal 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, 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:
General Electric Company: Docket No. FAA-2005-20944; Directorate
Identifier 2003-NE-64-AD.
Comments Due Date
(a) The Federal Aviation Administration (FAA) must receive
comments on this airworthiness directive (AD) action by June 14,
2005.
Affected ADs
(b) None.
Applicability: (c) This AD applies to General Electric Company
(GE) CT7-5A2, -5A3, -7A, -7A1, -9B, -9B1, and -9B2 turboprop
engines, with stage 2 turbine aft cooling plate, part number (P/N)
6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 installed. These
engines are installed on, but not limited to, Construcciones
Aeronauticas, SA CN-235 series and SAAB Aircraft AB SF340 series
airplanes.
Unsafe Condition
(d) This AD results from reports of six stage 2 turbine aft
cooling plates found cracked during inspection.
Compliance: (e) You are responsible for having the actions
required by this AD performed at the next engine or hot section
module shop visit, but before accumulating an additional 6,000
cycles-in-service after the effective date of the AD, unless already
done.
OneTime Eddy Current Inspection (ECI)
(f) Perform a onetime ECI of the stage 2 turbine aft cooling
plate boltholes, using paragraph 3.B. of GE Alert Service Bulletin
(ASB) No. CT7-TP S/B 72-A0464, Revision 2, dated May 9, 2003.
(g) Remove from service any stage 2 turbine aft cooling plate
that does not pass the return to service criteria specified in
paragraph 3.B.(2) of GE Alert Service Bulletin (ASB) No. CT7-TP S/B
72-A0464, Revision 2, dated May 9, 2003.
Previous Credit
(h) Previous credit is allowed for onetime ECIs of the stage 2
turbine aft cooling plate boltholes that were done using GE ASB No.
CT7-TP S/B 72-A0464, dated February 25, 2003, or GE ASB No. CT7-TP
S/B 72-A0464, Revision 1, dated March 12, 2003, before the effective
date of this AD.
Definition of Engine or Hot Section Module Shop Visit
(i) For the purposes of this AD, an engine or hot section module
shop visit is defined as the introduction of the engine or hot
section module into a shop that includes separation of CT7 turboprop
engine major case flanges.
Alternative Methods of Compliance
(j) The Manager, Engine 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
(k) None.
Issued in Burlington, Massachusetts, on April 11, 2005.
Robert E. Guyotte,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 05-7561 Filed 4-14-05; 8:45 am]
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