Airworthiness Directives; General Electric Company CF6-45 and CF6-50 Series Turbofan Engines

[Federal Register Volume 75, Number 51 (Wednesday, March 17, 2010)]
[Rules and Regulations]
[Pages 12661-12663]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-5777]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0068; Directorate Identifier 2010-NE-05-AD; 
Amendment 39-16240; AD 2010-06-15]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-45 and 
CF6-50 Series Turbofan 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 
General Electric Company (GE) CF6-45 and CF6-50 series turbofan engines 
with certain low-pressure turbine (LPT) stage 3 disks installed. This 
AD requires fluorescent penetrant inspection (FPI) of the LPT stage 3 
disk under certain conditions and removal of the disk from service 
before further flight if found cracked. This AD also requires initial 
and repetitive borescope inspections of the high-pressure turbine (HPT) 
rotor stage 1 and stage 2 blades for wear and damage, including 
excessive airfoil material loss. This AD results from three 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 critical life-limited rotating engine part failure, 
which could result in an uncontained engine failure and damage to the 
airplane.

DATES: This AD becomes effective April 1, 2010.

[[Page 12662]]

    We must receive any comments on this AD by May 17, 2010.

ADDRESSES: Use one of the following addresses to comment on this AD:
    <bullet> Federal eRulemaking Portal: Go to http://www.regulations.gov and follow the instructions for sending your 
comments electronically.
    <bullet> Mail: U.S. Docket Management Facility, Department of 
Transportation, 1200 New Jersey Avenue, SE., West Building Ground 
Floor, Room W12-140, Washington, DC 20590-0001.
    <bullet> Hand Delivery: Deliver to Mail address above between 9 
a.m. and 5 p.m., Monday through Friday, except Federal holidays.
    <bullet> 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]; telephone (781) 238-7133; fax 
(781) 238-7199.

SUPPLEMENTARY INFORMATION: Since July 2008, we received three 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. GE 
reports that these failures were caused by HPT rotor blade airfoil 
material loss which leads to LPT rotor unbalance, vibration, and LPT 
disk separation. GE's investigation also revealed that certain part 
number LPT stage 3 rotor disks could have micro-cracking on the inner 
diameter surface forward cone body (forward spacer arm) that, when 
exposed to rotor unbalance and other conditions, would allow crack 
growth and disk failure. 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 This AD

    The unsafe condition described previously is likely to exist or 
develop on other GE CF6-45 and CF6-50 series turbofan engines of the 
same type design. For that reason, we are issuing this AD to prevent 
critical life-limited rotating engine part failure, which could result 
in an uncontained engine failure and damage to the airplane. This AD 
requires FPI of the LPT stage 3 disk under the conditions described 
previously and permanent removal from service of the disk before 
further flight if found cracked. This AD also requires an initial 
borescope inspection of the HPT rotor for evidence of stage 1 and stage 
2 blade excessive airfoil material loss, within 50 cycles-in-service 
(CIS) after the effective date of this AD, and thereafter repetitive 
borescope inspections within every 175 CIS.

FAA's Determination of the Effective Date

    Since an unsafe condition exists that requires the immediate 
adoption of this AD, we have found that notice and opportunity for 
public comment before issuing this AD are impracticable, and that good 
cause exists for making this amendment effective in less than 30 days.

Interim Action

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

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 send us any written relevant data, 
views, or arguments regarding this AD. Send your comments to an address 
listed under ADDRESSES. Include ``AD Docket No. FAA-2010-0068; 
Directorate Identifier 2010-NE-05-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://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 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 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.

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 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 this 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. 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, 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:

[[Page 12663]]

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:

2010-06-15 General Electric Company: Amendment 39-16240. Docket No. 
FAA-2010-0068; Directorate Identifier 2010-NE-05-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective April 1, 
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, CF6-50C2F, CF6-50C2R, CF6-50E, CF6-50E1, and CF6-50E2, 
series turbofan engines, with any of the following low-pressure 
turbine (LPT) stage 3 disks installed:

------------------------------------------------------------------------
 
------------------------------------------------------------------------
  9061M23P06     9061M23P07     9061M23P08     9061M23P09    9224M75P01
  9061M23P10     1473M90P01     1473M90P02     1473M90P03    1473M90P04
  9061M23P12     9061M23P14     9061M23P15     9061M23P16    1479M75P01
  1479M75P02     1479M75P03     1479M75P04     1479M75P05    1479M75P06
  1479M75P07     1479M75P08     1479M75P09     1479M75P11    1479M75P13
  1479M75P14            N/A            N/A            N/A           N/A
------------------------------------------------------------------------

    These engines are installed on, but not limited to, Airbus A300 
series, Boeing 747 series, McDonnell Douglas DC-10 series, and DC-
10-30F (KDC-10) airplanes.

Unsafe Condition

    (d) This AD results from three 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 critical life-limited rotating engine part failure, 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 within the compliance times specified unless the 
actions have already been done.

Borescope Inspection of High-Pressure Turbine (HPT) Stage 1 and Stage 2 
Rotor Blades

    (f) Within 50 cycles-in-service (CIS) after the effective date 
of this AD, borescope-inspect the HPT stage 1 and stage 2 rotor 
blades for wear and damage, including excessive airfoil material 
loss.
    (g) Thereafter, within every 175 CIS, repetitively borescope-
inspect the HPT stage 1 and stage 2 rotor blades for wear and 
damage, including excessive airfoil material loss.

Actions Required Whenever the HPT Rotor Blade Cumulative Airfoil 
Material Loss is 50% of a Blade or More

    (h) Whenever the HPT rotor blade cumulative airfoil material 
loss is 50% of a blade or more, then before further flight, 
fluorescent penetrant inspect the inner diameter surface forward 
cone body (forward spacer arm) of the LPT stage 3 disk.
    (i) If the LPT stage 3 disk is cracked or if a circumferential 
band of fluorescence appears, permanently remove the disk from 
service.

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) 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]; telephone (781) 238-7133; fax (781) 
238-7199, for more information about this AD.

Material Incorporated by Reference

    (l) None.

    Issued in Burlington, Massachusetts on March 10, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-5777 Filed 3-16-10; 8:45 am]
BILLING CODE 4910-13-P

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