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

[Federal Register Volume 75, Number 110 (Wednesday, June 9, 2010)]
[Rules and Regulations]
[Pages 32649-32651]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 2010-13873]



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Federal Register / Vol. 75, No. 110 / Wednesday, June 9, 2010 / Rules 
and Regulations

[[Page 32649]]



DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2010-0068; Directorate Identifier 2010-NE-05-AD; 
Amendment 39-16331; AD 2010-12-10]
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.

-----------------------------------------------------------------------

SUMMARY: The FAA is superseding an existing airworthiness directive 
(AD) for General Electric Company (GE) CF6-45 and CF6-50 series 
turbofan engines with certain low-pressure turbine (LPT) rotor stage 3 
disks installed. That AD required 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. That AD also required fluorescent penetrant inspection (FPI) of 
the LPT rotor stage 3 disk under certain conditions and removal of the 
disk from service before further flight if found cracked. This ad 
requires the same inspections at reduced intervals and additional 
borescope inspections. This AD also requires repetitive exhaust gas 
temperature (EGT) system checks. This AD results from reports received 
of two additional LPT rotor stage 3 disk events. 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: Effective June 24, 2010.
    We must receive any comments on this AD by August 9, 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: Docket Management Facility, U.S. 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]; phone: (781) 238-7133; fax: (781) 
238-7199.

SUPPLEMENTARY INFORMATION: The FAA amends 14 CFR part 39 by superseding 
AD 2010-06-15, Amendment 39-16240 (75 FR 12661, March 17, 2010). That 
AD required initial and repetitive borescope inspections of the HPT 
rotor stage 1 and stage 2 blades for wear and damage, including 
excessive airfoil material loss. That AD also required FPI of the LPT 
rotor stage 3 disk under certain conditions and removal of the disk 
from service before further flight if found cracked. That AD was the 
result of three reports of uncontained failures of LPT rotor stage 3 
disks and eight reports of cracked LPT rotor stage 3 disks found during 
shop visit inspections. That condition, if not corrected, could result 
in an uncontained engine failure and damage to the airplane.

Actions Since AD 2010-06-15 Was Issued

    Since AD 2010-06-15 was issued, we received reports of two 
additional LPT rotor stage 3 disk events, bringing the total number of 
events to five. Additionally, the National Transportation Safety Board 
issued Safety Recommendations A-10-98 through A-10-101. These 
recommendations include performing a borescope inspection of the HPT 
rotor blades more frequently than was originally required in AD 2010-
06-15.

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 initial and repetitive borescope inspections of the HPT rotor 
stage 1 and stage 2 blades. This AD also requires additional borescope 
inspections and FPI of the LPT rotor stage 3 disk, depending on the 
results of the borescope inspection. This AD also requires repetitive 
EGT system checks.

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 ``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

[[Page 32650]]

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 (phone: (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:

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 removing Amendment 39-16240 (75 FR 
12661, March 17, 2010), and by adding a new airworthiness directive, 
Amendment 39-16331, to read as follows:

2010-12-10 General Electric Company: Amendment 39-16331. Docket No. 
FAA-2010-0068; Directorate Identifier 2010-NE-05-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective June 24, 
2010.

Affected ADs

    (b) This AD supersedes AD 2010-06-15, Amendment 39-16240.

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 any of the following low-pressure 
turbine (LPT) rotor 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, Boeing 747-
200/-300, DC-10, MD-10, and KC-10 aircraft, and Airbus A300 series 
aircraft.

Unsafe Condition

    (d) This AD results from reports received of two additional LPT 
rotor stage 3 disk events. 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 Inspections of High-Pressure Turbine (HPT) Rotor Stage 1 and 
Stage 2 Blades

    (f) Borescope-inspect the HPT rotor stage 1 and stage 2 blades 
from the forward and aft directions within 10 cycles from the 
effective date of this AD. You can find further guidance about 
borescoping in Table 2 of this AD.
    (g) Thereafter, borescope-inspect the HPT rotor stage 1 and 
stage 2 blades from the forward and aft directions within every 75 
cycles-since-last-inspection (CSLI). You can find further guidance 
about borescoping in Table 2 of this AD.

Additional Borescope Inspections

    (h) Borescope-inspect the HPT rotor stage 1 and stage 2 blades 
from the forward and aft directions within the cycle limits after 
the engine has experienced the events specified in Table 1 of this 
AD. You can find further guidance about borescoping in Table 2 of 
this AD.

            Table 1--Additional Borescope Inspection Criteria
------------------------------------------------------------------------
      If the engine has experienced:           Then borescope inspect:
------------------------------------------------------------------------
(1) An exhaust gas temperature (EGT) above  Within 10 cycles.
 redline.

[[Page 32651]]

 
(2) A shift in the smoothed EGT trending    Within 10 cycles.
 data that exceeds 18[deg] F (10[deg] C),
 but is less than or equal to 36[deg] F
 (20[deg] C).
(3) A shift in the smoothed EGT trending    Before further flight.
 data that exceeds 36[deg] F (20[deg] C).
(4) A flightcrew reported vibration         Within 10 cycles from the
 determined to be caused by the high-        report.
 pressure rotor (N2).
------------------------------------------------------------------------

Actions Required for Engines With Damaged HPT Rotor Blades

    (i) Remove the engine before further flight if the engine fails 
the borescope inspection in paragraph (f), (g), or (h) of this AD.
    (j) Before returning the engine to service, fluorescent 
penetrant inspect the inner diameter surface forward cone body 
(forward spacer arm) of the LPT rotor stage 3 disk. If a crack is 
found or if a circumferential band of fluorescence appears, 
permanently remove the disk from service.

EGT System Checks

    (k) Inspect the turbine midframe (TMF) liner for clocking and 
subsequent damage to the EGT probes, within 50 cycles from the 
effective date of this AD or before accumulating 750 CSLI of the TMF 
liner for clocking, whichever occurs later. You can find further 
guidance about TMF liner inspections in Table 2 of this AD.
    (l) Thereafter, inspect the TMF liner for clocking and 
subsequent damage to the EGT probes within every 750 CSLI. You can 
find further guidance about TMF liner inspections in Table 2 of this 
AD.
    (m) If the engine shows TMF liner clocking resulting in wear 
through 100% of the wall thickness of the thermocouple guide sleeve, 
remove the engine and repair the TMF and any damage to the EGT 
probes before further flight. You can find further guidance about 
TMF liner inspections in Table 2 of this AD.
    (n) Check the resistance of the EGT system within 50 cycles from 
the effective date of this AD or before accumulating 750 cycles-
since-the-last-resistance check of the EGT system, whichever occurs 
later. You can find further guidance about the EGT resistance check 
in Table 2 of this AD.
    (o) Thereafter, check the resistance of the EGT system within 
every 750 CSLI. You can find further guidance about EGT resistance 
checks in Table 2 of this AD.
    (p) Repair or replace any EGT system component that fails this 
check, before further flight. You can find further guidance about 
the EGT resistance check in Table 2 of this AD.

Definitions

    (q) For the purposes of this AD, an EGT above redline is a 
confirmed over temperature indication that is not a result of EGT 
system error. You can find further guidance about troubleshooting 
EGT above redline in Table 2 of this AD.
    (r) For the purposes of this AD, a shift in the smoothed EGT 
trending data is a shift in a rolling average of EGT that can be 
confirmed by a corresponding shift in the trending of fuel flow or 
fan speed/core speed relationship. You can find further guidance 
about evaluating EGT trend data in GE Company Service Rep Tip 373 
``Guidelines For Parameter Trend Monitoring.''

                                  Table 2--AMM References for Further Guidance
----------------------------------------------------------------------------------------------------------------
                                  Boeing 747/CF6-50/- Boeing  DC-10/CF6-  Boeing  MD-10/CF6-  Airbus A300/CF6-50
       Engine inspections             45 AMM ATA          50 AMM ATA          50 AMM ATA            AMM ATA
----------------------------------------------------------------------------------------------------------------
Borescope Inspection of HPT       72-00-00, 601.....  72-53-00..........  72-53-00..........  72-53-00.
 Rotor Stage 1 and Stage 2
 Blades.
Exceeded EGT Limit..............  72-00-00, 601.....  72-00-00, 601.....  72-00-00, 6-1.....  72-00-00, 601.
EGT Resistance Check............  77-21-00, 501.....  77-21-00..........  77-21-01..........  77-21-00.
TMF Liner Clocking..............  72-00-00, 601, and  72-54-00..........  72-54-00 and 77-21- 72-54-00.
                                   72-52-00.                               01.
----------------------------------------------------------------------------------------------------------------

Previous Credit

    (s) A borescope inspection performed before the effective date 
of this AD using AD 2010-06-15 and within the last 75 cycles, 
satisfies the initial borescope inspection requirement in paragraph 
(f) of this AD.

Alternative Methods of Compliance

    (t) Alternative methods of compliance previously approved for AD 
2010-06-15, are not approved for this AD.
    (u) 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

    (v) 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.

Material Incorporated by Reference

    (w) None.

    Issued in Burlington, Massachusetts, on June 4, 2010.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 2010-13873 Filed 6-7-10; 11:15 am]
BILLING CODE 4910-13-P

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