[Federal Register Volume 71, Number 62 (Friday, March 31, 2006)]
[Proposed Rules]
[Pages 16248-16250]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-4700]


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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), Department of 
Transportation (DOT).

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The FAA proposes to supersede an existing airworthiness 
directive (AD) for General Electric Company (GE) CT7-5A2, -5A3, -7A, -
7A1, -9B, -9B1, and -9B2 turboprop engines, with certain part number 
(P/N) and serial number stage 2 turbine aft cooling plates installed. 
That AD currently requires a onetime eddy current inspection (ECI) of 
boltholes in certain P/N stage 2 turbine aft cooling plates. This 
proposed AD would expand the population of affected CT7 turboprop 
engine models, but would reduce the number of cooling plates affected. 
It would also require a onetime ECI of boltholes in certain P/N stage 2 
turbine aft cooling plates. This proposed AD results from the 
manufacturer identifying the affected stage 2 turbine aft cooling 
plates by serial number. We are proposing this AD to prevent separation 
of the stage 2 turbine aft cooling plate, resulting in uncontained 
engine failure and damage to the airplane.

DATES: We must receive any comments on this proposed AD by May 30, 
2006.

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.
    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.

FOR FURTHER INFORMATION CONTACT: Mark Bouyer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England Executive 
Park, Burlington, MA 01803; telephone (781) 238-7755; fax (781) 238-
7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    We invite you to send 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

    On April 19, 2005, the FAA issued AD 2005-18-01, Amendment 39-14247 
(70 FR 54835, September 19, 2005). That AD requires a onetime ECI of 
boltholes in certain P/N stage 2 turbine aft cooling plates. That AD 
resulted from reports of six stage 2 turbine aft cooling plate 
boltholes found cracked during inspection. That condition, if not 
corrected, could result in stage 2 turbine aft cooling plate 
separation, resulting in uncontained engine failure and damage to the 
airplane.

Actions Since AD 2005-18-01 Was Issued

    Since that AD was issued, GE determined that it is necessary to 
expand the population of affected CT7 turboprop engine models to 
include CT7-9C/-9C3/-9D/-9D2 turboprop engines with stage 2 turbine aft 
cooling plate P/N 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01 
installed. GE also defined the affected population of cooling plates by 
serial number. This proposed AD includes these model engines.

[[Page 16249]]

Relevant Service Information

    We have reviewed and approved the technical contents of GE Alert 
Service Bulletin CT7-TP S/B 72-A0464, Revision 4, dated December 12, 
2005, that describes procedures for performing an ECI of boltholes in 
certain P/N stage 2 turbine aft cooling plates and replacing the 
cooling plate, if necessary, with one with a serial number not listed 
in Section 4, Appendix A, of the SB.

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. For that reason, we are proposing this AD, 
which would expand the population of affected CT7 turboprop engine 
models, but would reduce the actual cooling plate population by 
specifying the affected cooling plates by serial number. This proposed 
AD would also require a onetime ECI of boltholes in certain P/N stage 2 
turbine aft cooling plates, and replacement of the cooling plates if 
necessary. The proposed AD would require that you do these actions 
using the service information described previously.

Costs of Compliance

    We estimate that this proposed AD would affect 494 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 1 work hour per engine to perform the proposed actions, and 
that the average labor rate is $80 per work hour. Based on the number 
of cracks found in the inspected engines, we estimate that 2.5% of the 
494 engines will require replacing stage 2 turbine aft cooling plates 
because of rejection 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 $243,520.

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 removing Amendment 39-14247 (70 FR 
54835, September 19, 2005) and by adding a new airworthiness directive, 
to read as follows:

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 May 30, 
2006.

Affected ADs

    (b) This AD supersedes AD 05-18-01, Amendment 39-14247.

Applicability

    (c) This AD applies to General Electric Company (GE) CT7-5A2/-
5A3/-7A/-7A1/-9B/-9B1/-9B2/-9C/-9C3/-9D/-9D2 turboprop engines with 
stage 2 turbine aft cooling plates, 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 the manufacturer identifying the 
affected stage 2 turbine aft cooling plates by serial number. We are 
issuing this AD to prevent separation of the stage 2 turbine aft 
cooling plate, resulting in uncontained engine failure and damage to 
the airplane.

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 
plates P/N 6064T07P01, 6064T07P02, 6064T07P05, or 6068T36P01, that 
are listed by serial number in Section 4, Appendix A, of GE Alert 
Service Bulletin No. CT7-TP S/B 72-A0464, Revision 04, dated 
December 12, 2005. Use 3.(1) through 3.B.(3) of GE Alert Service 
Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 4, dated December 
12, 2005 to perform the inspection.
    (g) For stage 2 turbine aft cooling plates that do not pass the 
Return to Service Criteria, do either of the following:
    (1) Replace the stage 2 turbine aft cooling plate with a new 
cooling plate that has a serial number that is not listed in Section 
4, Appendix A, of GE Alert Service Bulletin No. CT7-TP S/B 72-A0464, 
Revision 04, dated December 12, 2005, or
    (2) Replace the stage 2 turbine aft cooling plate with a cooling 
plate that meets the acceptance criteria of 3.B.(1) through 3.B.(3) 
of GE Alert Service Bulletin (ASB) No. CT7-TP S/B 72-A0464, Revision 
4, dated December 12, 2005.
    (h) After the effective date of this AD, do not install any 
stage 2 turbine aft cooling plates with serial numbers identified in 
Section 4, Appendix A, without inspecting the cooling plate as 
specified in 3.B.(1) through 3.B.(3) of GE Alert Service Bulletin 
No. CT7-TP S/B 72-A0464 Revision 04, December 12, 2005.

Previous Credit

    (i) Eddy current inspections of the stage 2 turbine aft cooling 
plate boltholes done before the effective date of this AD that use 
GE ASB No. CT7-TP S/B 72-A0464, dated February 25, 2003; or Revision 
1, dated March 12, 2003; or Revision 2, dated May 9,

[[Page 16250]]

2003; or Revision 3, dated July 23, 2004, comply with the 
requirements specified in this AD.

Definition of Engine or Hot Section Module Shop Visit

    (j) 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 separating major case 
flanges.

Alternative Methods of Compliance

    (k) 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

    (l) None.

    Issued in Burlington, Massachusetts, on March 24, 2006.
Thomas Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E6-4700 Filed 3-30-06; 8:45 am]
BILLING CODE 4910-13-P