Document ID: FAA-2007-28367-0015
Agency: faa
Document Type: Rule
Title: Airworthiness Directives; General Electric Company CF6-80C2 Series and CF6-80E1 Series Turbofan Engines
Posted Date: 2008-10-24T04:00Z

[Federal Register: October 24, 2008 (Volume 73, Number 207)]
[Rules and Regulations]               
[Page 63354-63357]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr24oc08-6]                         

[[Page 63354]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2007-28367; Directorate Identifier 2007-NE-19-AD; 
Amendment 39-15695; AD 2008-21-11]
RIN 2120-AA64

 
Airworthiness Directives; General Electric Company CF6-80C2 
Series and CF6-80E1 Series Turbofan Engines

AGENCY: Federal Aviation Administration (FAA), Department of 
Transportation (DOT).

ACTION: Final rule.

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

SUMMARY: The FAA is adopting a new airworthiness directive (AD) for 
General Electric Company (GE) CF6-80C2 series and CF6-80E1 series 
turbofan engines. This AD requires installing skin doubler pads and 
deflectors on stage 5 of certain low-pressure turbine (LPT) cases, or 
replacing those LPT cases with LPT cases that have skin doubler pads 
and deflectors already installed. This AD results from four events in 
which hardware fragments were liberated into the engine flowpath and 
wore through LPT cases on CF6-80C2 and CF6-80E1 series engines. We are 
issuing this AD to prevent an uncontained release of engine debris and 
loss of the structural integrity of the mount system that supports the 
engine. Loss of the mount system structural integrity could result in 
the engine separating from the airplane.

DATES: This AD becomes effective November 28, 2008. The Director of the 
Federal Register approved the incorporation by reference of certain 
publications listed in the regulations as of November 28, 2008.

ADDRESSES: You can get the service information identified in this AD 
from Customer Support Center, GE Aircraft Engines, M/D Center Rm 285, 
One Neumann Way, Cincinnati, OH 45216, U.S.A.; e-mail: 
geae.csc@ae.ge.com; International phone No.: (513)-552-3272; U.S.A. 
phone No.: 877-432-3272.
    The Docket Operations office is located at Docket Management 
Facility, U.S. Department of Transportation, 1200 New Jersey Avenue, 
SE., West Building Ground Floor, Room W12-140, Washington, DC 20590-
0001.

FOR FURTHER INFORMATION CONTACT: James Rosa, Aerospace Engineer, Engine 
Certification Office, FAA, Engine and Propeller Directorate, 12 New 
England Executive Park, Burlington, MA 01803; e-mail: 
james.rosa@faa.gov; telephone (781) 238-7152; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: The FAA proposed to amend 14 CFR part 39 
with a proposed AD. The proposed AD applies to CF6-80C2 series and CF6-
80E1 series turbofan engines. We published the proposed AD in the 
Federal Register on September 19, 2007 (72 FR 53491). That action 
proposed to require installing skin doubler pads and deflectors on 
stage 5 of certain LPT cases, or replacing those LPT cases with LPT 
cases that have the skin doubler pads and deflectors already installed.

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 provided in 
the ADDRESSES section. Comments will be available in the AD docket 
shortly after receipt.

Comments

    We provided the public the opportunity to participate in the 
development of this AD. We have considered the comments received.

Request To Eliminate the AD Action Compliance Date

    One commenter, a private citizen, requests that we eliminate the AD 
action compliance date, as it might cause premature removals of LPT 
modules and increase the anticipated cost of compliance.
    We do not agree. The compliance date is necessary to maintain the 
airworthiness of the U.S. engine fleet. We did not change the AD.

Request for Previous Credit

    Three carriers and two private citizens request previous credit for 
complying with earlier versions of the applicable GE service documents, 
before the effective date of the AD. The commenters state that they 
have already modified some engines to correct the unsafe condition.
    We agree. The original versions of the service bulletins (SBs) are 
technically the same as the Revision 1 versions. GE Repair Document 
(RD) No. 935-314-S2 and RD No. 935-314-S3 are technically the same as 
the RD No. 935-314-S4 version. We added a paragraph to allow for 
previous credit of these documents. GE issued RD No. 935-314-S4 after 
we issued the proposed AD, which we now reference in the AD.

Request To Increase the Compliance Period From 8 Years, to 10 Years or 
11 Years

    One carrier requests that we increase the compliance period from 8 
years to 10 years, and another carrier and a private citizen request we 
increase the compliance period to 11 years, after the effective date of 
the AD. The commenters point out that GE considered it acceptable to 
not specify any compliance period in their service bulletins. The 
commenters feel that increasing the compliance period does not 
negatively impact safety.
    We do not agree. The 8-year AD compliance period will give the 
operators a total of 11 years from the introduction of the service 
bulletins. The compliance date is necessary to maintain the 
airworthiness of the U.S. engine fleet. We did not change the AD.

Request To Change the Compliance Description

    Two carriers and one private citizen request that we change the 
compliance description from ``next time the LPT module is 
disassembled'' to ``next time the LPT module is completely disassembled 
to piece-part level'', as the proposed AD compliance does not clearly 
describe the compliance requirement.
    We agree. We changed the AD.

Request To Clear Up the Contradiction Between the All Operators Wire 
(AOW) and the Proposed AD

    One carrier requests that we clear up a contradiction between the 
AOW and the proposed AD regarding the compliance time. The commenter 
states that, although the FAA informed the operators through the AOW 
that compliance was required at the next disassembly of the LPT module, 
the proposed AD would require compliance the next time the LPT was 
disassembled or within the next 8 years after the effective date of the 
AD.
    We do not agree. AOWs are published and distributed by the 
manufacturer, not the FAA. The proposed AD compliance requirement 
stated ``the next disassembly of the LPT module'', which has been 
changed in the AD to state ``the next time the LPT module is completely 
disassembled to piece-part level.'' If the LPT module is not 
disassembled for 8 years after the effective date of the AD, the 
operator cannot operate the engine until the mandatory AD action is 
completed. The 8-year compliance date is necessary to maintain the

[[Page 63355]]

airworthiness of the U.S. engine fleet. We did not change the AD.

Request To Delete the Revision and Date References to GE RD No. 935-314

    Three carriers and one private citizen request that we delete 
references to the issue date and revision number of GE RD No. 935-314, 
and also change the AD to allow use of future revisions of that 
document. This would eliminate having to revise the final rule if the 
document is revised.
    We do not agree. We are legally required to specify the complete 
identification of the service document, including its revision number 
and issue date. We cannot legally reference future revisions of a 
document, as we have no way of knowing the accuracy or applicability of 
such documents. We did not change the AD.

Request To Distinguish Between Doubler Pads and Deflectors

    One carrier and one private citizen request that we distinguish 
between ``doubler pads'' and ``deflectors'' in the AD. The proposed AD 
implies that they are the same part, but they are not the same.
    We agree. We clarified in the AD that these parts are distinct and 
separate.

Request To Correct a Temperature Conversion Error in the GE RD No. 935-
314

    One carrier requests that we correct a temperature conversion error 
in paragraph F.6.(a) of GE RD No. 935-314-S3.
    We agree there is a temperature conversion error in that document. 
GE issued RD No. 935-314-S4, dated January 28, 2008, which corrected 
that error. We now reference RD No. 935-314-S4 in the AD.

Request To Change the Compliance To Occur When the Turbine Rear Frame 
Is Removed From the LPT Case

    One carrier requests that we change the compliance to occur when 
the turbine rear frame is removed from the LPT case, as the LPT module 
consists of the LPT case and turbine rear frame. The commenter states 
that the proposed AD, as written, will overburden their maintenance 
system by requiring the AD modification every time an LPT module is 
removed.
    We do not agree. The AD must be complied with when the LPT module 
is completely disassembled to piece-part level. Removal of the LPT 
module to service the turbine rear frame will not require compliance 
with this AD. We did not change the AD.

Request To Withdraw the Proposed AD

    The Air Transport Association requests that we withdraw the 
proposed AD. The commenter states that a hazardous or unsafe condition 
does not exist, and there is no need for an AD. The commenter quotes 
figures derived from probability calculations, among them Table 1 of 
the Risk Guidelines from FAA Advisory Circular (AC) 39-8 as ``Long-term 
acceptable risk'' for the subject of the proposed AD, and therefore 
indicates that the regulations do not require an AD.
    We do not agree. The purpose of the Risk Guidelines in the AC is to 
determine how quickly action should be taken to maintain the 
airworthiness of an aircraft engine; not to decide if action is to be 
taken. Paragraph 1.(c) of the AC states ``Continued Airworthiness 
Assessment Methodologies (CAAM) assist the FAA in making decisions 
concerning the priority in which unsafe conditions should be addressed. 
The FAA may issue an AD for a particular unsafe condition before a risk 
assessment is performed, or without having an assessment performed at 
all.'' Furthermore, determination of an unsafe condition is the 
responsibility of the FAA Administrator, and we have found there is 
adequate evidence indicating an unsafe condition exists in this case.
    14 CFR Part 33.19 requires that ``Engine design and construction 
must minimize the development of an unsafe condition of the engine 
between overhaul periods. The design of the compressor and turbine 
rotor cases must provide for the containment of damage from rotor blade 
failure.'' Instances of LPT case holes have been recorded, making those 
LPT cases unable to contain liberated stage five blades (or other 
engine hardware).
    We have no data to indicate that the mount system would function as 
intended after an incident when the LPT case was rubbed through 
completely. We did not change the AD.

Request To Allow Exemption From the AD

    One carrier requests that they be allowed an exemption from the AD, 
as they have complied with all primary-cause correction ADs.
    We do not agree. Similar LPT case failures could occur during the 
time allowed to comply with primary-cause ADs, or as a result of future 
unforeseen events. Since the LPT case has shown to be unable to 
withstand engine failures, we are required to mandate that the LPT case 
be changed to meet airworthiness requirements. We do not exempt the 
operator from the AD.

Conclusion

    We have carefully reviewed the available data, including the 
comments received, and determined that air safety and the public 
interest require adopting the AD with the changes described previously. 
We have determined that these changes will neither increase the 
economic burden on any operator nor increase the scope of the AD.

Costs of Compliance

    We estimate that this AD will affect 854 GE CF6 engines installed 
on airplanes of U.S. registry. We also estimate that it will take about 
30 work-hours per engine to perform the actions, and that the average 
labor rate is $80 per work-hour. Required parts will cost about $10,170 
per engine. Based on these figures, we estimate the total cost of the 
AD to U.S. operators to be $10,734,780.

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 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

[[Page 63356]]

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, Incorporation by 
reference, Safety.

Adoption of the Amendment

0
Accordingly, under the authority delegated to me by the Administrator, 
the Federal Aviation Administration amends 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 adding the following new airworthiness 
directive:

2008-21-11 General Electric Company: Amendment 39-15695. Docket No. 
FAA-2007-28367; Directorate Identifier 2007-NE-19-AD.

Effective Date

    (a) This airworthiness directive (AD) becomes effective November 
28, 2008.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the General Electric Company (GE) CF6-
80C2 and CF6-80E1 engines specified in the following Table 1 of this 
AD. These engines are installed on, but not limited to, Airbus A300, 
A310, and A330 series airplanes, Boeing 747 and 767 series 
airplanes, and McDonnell Douglas MD11 series airplanes.

               Table 1--Applicable Engines by Engine Model
------------------------------------------------------------------------
                                         With Low-Pressure Turbine (LPT)
              Engine model                Case Part No. (P/N) Installed
------------------------------------------------------------------------
CF6-80C2A1, -80C2A2, -80C2A3, -80C2A5, - 1336M99G01, 1336M99G02,
 80C2A5F, -80C2A8, -80C2B1, -80C2B1F, -   1336M99G03, 1336M99G04,
 80C2B1F1, -80C2B1F2, -80C2B2, -          1336M99G06, 1336M99G07,
 80C2B2F, -80C2B3F, -80C2B4, -80C2B4F, -  1336M99G08, 1336M99G09,
 80C2B5F, -80C2B6, -80C2B6F, -80C2B6FA,   1336M99G10, 1336M99G12,
 -80C2B7F, -80C2B8F, -80C2D1F, and -      1336M99G13, or 1336M99G15.
 80C2L1F.                                1647M68G05, 1647M68G08,
                                          1647M68G09, or 1647M68G15.
                                         1713M73G01, 1713M73G02, or
                                          1713M73G05.
                                         9367M99G11or 9367M99G17.
CF6-80E1A1, -80E1A2, -80E1A3, -80E1A4, - 1647M68G02, 1647M68G04,
 80E1A4/B.                                1647M68G07, 1647M68G12, or
                                          1647M68G13.
------------------------------------------------------------------------

Unsafe Condition

    (d) This AD results from four events in which hardware fragments 
were liberated into the engine flowpath and wore through LPT cases 
on CF6-80C2 and CF6-80E1 series engines. We are issuing this AD to 
prevent an uncontained release of engine debris and loss of the 
structural integrity of the mount system that supports the engine. 
Loss of the mount system structural integrity could result in the 
engine separating from the airplane.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed the next time the LPT module is completely disassembled 
to piece-part level, but not to exceed 8 years after the effective 
date of this AD, unless the actions have already been done.

CF6-80C2 Engines

    (f) For CF6-80C2 engines specified in Table 1 of this AD that 
have an LPT case with a P/N specified in Table 1 of this AD, do 
either of the following:
    (1) Rework the LPT case to install skin doubler pads and 
deflectors. Use the Accomplishment Instructions of GE Service 
Bulletin (SB) No. CF6-80C2 S/B 72-1171, Revision 1, dated February 
1, 2006, and Repair Document (RD) No. 935-314-S4, dated January 28, 
2008, to rework the LPT case, or
    (2) Install an LPT case that has skin doubler pads and 
deflectors.

CF6-80E1 Engines

    (g) For CF6-80E1 engines specified in Table 1 of this AD that 
have an LPT case with a P/N specified in Table 1 of this AD, do 
either of the following:
    (1) Rework the LPT case to install skin doubler pads and 
deflectors. Use the Accomplishment Instructions of SB No. CF6-80E1 
S/B 72-0303, Revision 1, dated February 1, 2006, and RD No. 935-314-
S4, dated January 28, 2008, to rework the LPT case, or
    (2) Install an LPT case that has skin doubler pads and 
deflectors.

Previous Credit

    (h) If you previously performed the actions specified in 
paragraphs (f) through (g)(2) of this AD, using the rework 
procedures in the following service documents before the effective 
date of this AD, you have satisfied the compliance requirements of 
this AD:
    (1) GE SB No. CF6-80C2 S/B 72-1171, dated May 25, 2005 and RD 
No. 935-314-S2, dated January 4, 2006, or RD No. 935-314-S3, dated 
August 10, 2006.
    (2) GE SB No. CF6-80E1 S/B 72-0303, dated June 1, 2005 and RD 
No. 935-314-S2, dated January 4, 2006, or RD No. 935-314-S3, dated 
August 10, 2006.

Parts Identification

    (i) LPT case skin doubler pads and deflectors are distinct and 
separate parts. For identification purposes, a deflector pad is a 
square-shaped plate with no threaded stud on it, and a deflector has 
a threaded stud on it.

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 James Rosa, Aerospace Engineer, Engine Certification 
Office, FAA, Engine and Propeller Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: james.rosa@faa.gov; 
telephone (781) 238-7152; fax (781) 238-7199, for more information 
about this AD.

Material Incorporated by Reference

    (l) You must use the service information specified in Table 2 of 
this AD to perform the rework required by this AD. The Director of 
the Federal Register approved the incorporation by reference of the 
documents listed in Table 2 of this AD in accordance with 5 U.S.C. 
552(a) and 1 CFR part 51. Contact Customer Support Center, GE 
Aircraft Engines, M/D Center Rm 285, One Neumann Way, Cincinnati, OH 
45216, U.S.A.; e-mail: geae.csc@ae.ge.com; International phone No.: 
(513) 552-3272; U.S.A. phone No.: 877-432-3272, for a copy of this 
service information. You may review copies at the FAA, New England 
Region, 12 New England Executive Park, Burlington, MA; or at the 
National Archives and Records Administration (NARA). For information 
on the availability of this material at NARA, call 202-741-6030, or 
go to: http://www.archives.gov/federal-register/cfr/ibr-
locations.html.

[[Page 63357]]

                                       Table 2--Incorporation by Reference
----------------------------------------------------------------------------------------------------------------
 GE Service Bulletin/Repair Document No.           Page            Revision                  Date
----------------------------------------------------------------------------------------------------------------
CF6-80C2 S/B 72-1171....................  ALL...................          1  February 1, 2006.
    Total Pages: 10.....................
CF6-80E1 S/B 72-0303....................  ALL...................          1  February 1, 2006.
    Total Pages: 7......................
Repair Document (RD) 935-314-S4.........  ALL...................          4  January 28, 2008.
    Total Pages: 39.....................
----------------------------------------------------------------------------------------------------------------

    Issued in Burlington, Massachusetts, on October 10, 2008.
Peter A. White,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
 [FR Doc. E8-24874 Filed 10-23-08; 8:45 am]

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