

[Federal Register: September 19, 2007 (Volume 72, Number 181)]
[Proposed Rules]               
[Page 53491-53493]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr19se07-22]                         

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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]
RIN 2120-AA64

 
Airworthiness Directives; General Electric Company (GE) CF6-80C2 
Series and CF6-80E1 Series Turbofan 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 adopt a new airworthiness directive (AD) 
for GE CF6-80C2 series and CF6-80E1 series turbofan engines. This 
proposed AD would require installing doubler pads (deflectors) on stage 
5 of certain LPT cases, or replacing those LPT cases with LPT cases 
that have the deflectors already installed. This proposed AD results 
from four events of hardware

[[Page 53492]]

fragments, which liberated into the flowpaths and wore through LPT 
cases on CF6-80C2 and -80E1 series engines. We are proposing 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: We must receive any comments on this proposed AD by November 19, 
2007.

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, 1200 New Jersey Avenue, SE., West Building, Ground 
Floor, Room W12-140, Washington, DC 20590.
     Fax: (202) 493-2251.
     Hand Delivery: 1200 New Jersey Avenue, SE., West Building, 
Ground Floor, Room W12-140, Washington, DC, between 9 a.m. and 5 p.m., 
Monday through Friday, except Federal holidays.
    You can get the service information identified in this proposed 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.
    You may examine the comments on this proposed AD in the AD docket 
on the Internet at http://dms.dot.gov.


FOR FURTHER INFORMATION CONTACT: Robert Green, Aerospace Engineer, 
Engine Certification Office, FAA, Engine & Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: robert.green@faa.gov; 
telephone (781) 238-7754; 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-2007-28367; 
Directorate Identifier 2007-NE-19-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 
DOT 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 Docket Management 
Facility between 9 a.m. and 5 p.m., Monday through Friday, except 
Federal holidays. The Docket Office (telephone (800) 647-5527) is 
located at the street address stated in ADDRESSES. Comments will be 
available in the AD docket shortly after the Docket Management Facility 
receives them.

Discussion

    We have received reports of four events, three on CF6-80C2 engines, 
and one on a CF6-80E1 engine, where the LPT case experienced up to 360 
degrees circumferentially of wear and breach of the casing from 
separate failures of the high pressure turbine (HPT) stage 2 nozzle and 
the fan mid shaft. Such internal engine failures can result in rotor 
blade and nozzle vane fragments entering the LPT.
    The geometry of the blade plane of the stage 5 LPT rotor allows the 
liberated fragments to accumulate between the LPT blade tips and the 
LPT case. Engine operation, even at reduced power or windmilling, 
causes accumulated debris to wear through the LPT case wall. Such a 
breach from internal engine failure can result in an uncontained 
release of engine debris and loss of the structural integrity of the 
mount system that supports the engine. This condition, if not 
corrected, could result in the engine separating from the airplane.

Relevant Service Information

    We have reviewed and approved the technical contents of Service 
Bulletin (SB) CF6-80E1 S/B 72-0303, Revision 1, dated February 1, 2006; 
SB CF6-80C2 S/B 72-1171, Revision 1, dated February 1, 2006; and GE 
Repair Document RD 935-314-S3, dated August 10, 2006, that describes 
procedures for installing case skin doubler pads (deflectors) on stage 
5 of the LPT case.

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 
installing case skin doubler pads (deflectors) on stage 5 of the 
affected LPT case or replacing the case with a case that has deflectors 
installed, at the next disassembly of the LPT module after the 
effective date of the proposed AD. The proposed AD would require you to 
use the service information described previously to perform these 
actions.

Costs of Compliance

    We estimate that this proposed AD would affect 854 GE CF6 engines 
installed on airplanes of U.S. registry. We also estimate that it would 
take about 30 work-hours per engine to perform the proposed actions, 
and that the average labor rate is $80 per work-hour. Required parts 
would cost about $10,170 per engine. Based on these figures, we 
estimate the total cost of the proposed 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 proposed AD would not have federalism 
implications under Executive Order

[[Page 53493]]

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 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-2007-28367; Directorate 
Identifier 2007-NE-19-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by November 19, 
2007.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to the 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, 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 of hardware fragments, 
which liberated into the flowpaths and wore through LPT cases on 
CF6-80C2 and -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 disassembled, 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 deflectors. Use the 
Accomplishment Instructions of GE Service Bulletin (SB) CF6-80C2 S/B 
72-1171, Revision 1, dated February 1, 2006, and Repair Document 
(RD) 935-314-S3, dated August 10, 2006, to rework the LPT case, or
    (2) Install an LPT case that has case skin doubler pads.

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 deflectors. Use the 
Accomplishment Instructions of SB CF6-80E1 S/B 72-0303, Revision 1, 
dated February 1, 2006, and RD 935-314-S3, dated August 10, 2006, to 
rework the LPT case, or
    (2) Install an LPT case that has case skin doubler pads.

Alternative Methods of Compliance

    (h) 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

    (i) None.
    (j) Contact Robert Green, Aerospace Engineer, Engine 
Certification Office, FAA, Engine & Directorate, 12 New England 
Executive Park, Burlington, MA 01803; e-mail: robert.green@faa.gov; 
telephone (781) 238-7754; fax (781) 238-7199, for more information 
about this AD.

    Issued in Burlington, Massachusetts, on September 11, 2007.
Francis A. Favara,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
 [FR Doc. E7-18418 Filed 9-18-07; 8:45 am]

BILLING CODE 4910-13-P
