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[Federal Register Volume 75, Number 202 (Wednesday, October 20, 2010)]
[Proposed Rules]
[Pages 64681-64683]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-26312]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0998; Directorate Identifier 2010-NE-29-AD]
RIN 2120-AA64

Airworthiness Directives; General Electric Company (GE) CF6-45 
Series and CF6-50 Series Turbofan 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 GE CF6-45 and CF6-50 series turbofan engines. This proposed AD 
would require performing a fluorescent penetrant inspection (FPI) of 
the stage 3 low-pressure turbine (LPT) rotor at every shop visit at 
which the LPT module is separated from the engine. This proposed AD 
results from seven

[[Page 64682]]

reports of uncontained failures of LPT stage 3 disks and eight reports 
of cracked LPT stage 3 disks found during shop visit inspections. We 
are proposing this AD to prevent LPT rotor separation, which could 
result in an uncontained engine failure and damage to the airplane.

DATES: We must receive any comments on this proposed AD by December 20, 
2010.

ADDRESSES: Use one of the following addresses to comment on this 
proposed AD.
     Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
     Mail: Docket Management Facility, U.S. Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
     Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
     Fax: (202) 493-2251.

FOR FURTHER INFORMATION CONTACT: Christopher J. Richards, Aerospace 
Engineer, Engine Certification Office, FAA, Engine & Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803; e-
mail: [email protected]; phone: (781) 238-7133; fax: (781) 
238-7199.

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-2010-0998; Directorate 
Identifier 2010-NE-29-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://www.regulations.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 Web site, anyone can find and read the comments in any 
of our dockets, including, if provided, 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).

Examining the AD Docket

    You may examine the AD docket on the Internet at http://www.regulations.gov; or in person at the Docket Operations office 
between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The AD docket contains this proposed AD, the regulatory 
evaluation, any comments received, and other information. The street 
address for the Docket Operations office (telephone (800) 647-5527) is 
the same as the Mail address provided in the ADDRESSES section. 
Comments will be available in the AD docket shortly after receipt.

Discussion

    Since July 2008, we have received seven reports of uncontained 
failures of LPT stage 3 rotor disks and eight reports of cracked LPT 
rotor stage 3 disks found during shop visit inspections. Our 
investigation revealed that certain part number LPT stage 3 rotor disks 
might fail due to circumferential cracking of the forward cone body 
(forward spacer arm) of the LPT stage 3 disk when exposed to core 
engine (N2) vibrations. On June 4, 2010, we issued AD 2010-12-10 that 
requires a separate set of corrective actions. Those actions, along 
with this proposed AD, reduce the likelihood of further uncontained 
engine failures. This condition, if not corrected, could result in 
critical life-limited rotating engine part failure, which could result 
in an uncontained engine 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 would require 
performing a fluorescent penetrant inspection at every shop visit when 
the LPT module is separated from the engine.

Interim Action

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

Costs of Compliance

    We estimate that this proposed AD would affect 387 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 7 work-hours per engine to perform the proposed actions, and 
that the average labor rate is $85 per work-hour. No parts would be 
required. Based on these figures, we estimate the total cost of the 
proposed AD to U.S. operators to be $230,265.

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 AD:
    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. 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

[[Page 64683]]

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-2010-0998; Directorate 
Identifier 2010-NE-29-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by December 20, 
2010.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF6-45A, 
CF6-45A2, CF6-50A, CF6-50C, CF6-50CA, CF6-50C1, CF6-50C2, CF6-50C2B, 
CF6-50C2D, CF6-50C2-F, CF6-50C2-R, CF6-50E, CF6-50E1, and CF6-50E2 
series turbofan engines, with a low-pressure turbine (LPT) rotor 
stage 3 disk that has a part number (P/N) listed in Table 1 of this 
AD installed:

                  Table 1--LPT Rotor Stage 3 Disk P/Ns
------------------------------------------------------------------------
 
------------------------------------------------------------------------
     1473M90P01         1473M90P02        1473M90P03        1473M90P04
     1479M75P01         1479M75P02        1479M75P03        1479M75P04
     1479M75P05         1479M75P06        1479M75P07        1479M75P08
     1479M75P09         1479M75P11        1479M75P13        1479M75P14
     9061M23P06         9061M23P07        9061M23P08        9061M23P09
     9061M23P10         9061M23P12        9061M23P14        9061M23P15
     9061M23P16         9224M75P01
------------------------------------------------------------------------

    These engines are installed on, but not limited to, Boeing 747-
200B series, -200C series, and -200F series, 747-300 series 
airplanes; McDonnell Douglas DC-10-15, -30, and -30F, MD-10-30, KC-
10A, and KDC-10 airplanes; and Airbus A300 series airplanes.

Unsafe Condition

    (d) This AD results from seven reports of uncontained failures 
of LPT stage 3 disks and eight reports of cracked LPT stage 3 disks 
found during shop visit inspections. We are issuing this AD to 
prevent LPT rotor separation, which could result in an uncontained 
engine failure and damage to the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed at each shop visit after the effective date of this AD, 
at which the LPT module is separated from the engine.

Cleaning the LPT Stage 3 Disk

    (f) Clean the LPT stage 3 disk, using a wet-abrasive blast to 
eliminate residual or background fluorescence. You can find guidance 
on cleaning the disk in the cleaning procedure of CF6-50 Engine 
Manual, GEK 50481 72-57-02.

Inspecting the LPT Stage 3 Disk

    (g) Perform a fluorescent penetrant inspection (FPI) of the 
inner diameter of the forward cone body (forward spacer arm) of the 
LPT stage 3 disk. You can find guidance on performing the FPI in the 
CF6-50 Engine Manual, GEK 50481 72-57-02.
    (h) If a crack or a band of fluorescence is present, remove the 
disk from service.

Alternative Methods of Compliance

    (i) 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

    (j) Contact Christopher J. Richards, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
[email protected]; phone: (781) 238-7133; fax: (781) 
238-7199, for more information about this AD.

    Issued in Burlington, Massachusetts, on October 8, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-26312 Filed 10-19-10; 8:45 am]
BILLING CODE 4910-13-P
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