[Federal Register Volume 71, Number 62 (Friday, March 31, 2006)]
[Proposed Rules]
[Pages 16246-16248]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: E6-4702]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. FAA-2006-24145; Directorate Identifier 2006-NE-06-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-45 and 
CF6-50 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 certain General Electric Company (GE) CF6-45 and CF6-50 series 
turbofan engines. This proposed AD would require inspecting and 
reworking certain forward and aft center bodies of the long fixed core 
exhaust nozzle (LFCEN) assembly. This proposed AD results from reports 
of separation of LFCEN assembly forward and aft center bodies, due to 
high imbalance engine conditions during flight. We are proposing this 
AD to prevent the forward and aft center body of the LFCEN assembly 
from separating, leading to additional damage to the engine and 
airplane, possible damage to other airplanes, and to objects on the 
ground.

DATES: We must receive any comments on this proposed AD by May 30, 
2006.

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, 400 Seventh Street, SW., Nassif Building, Room PL-401, 
Washington, DC 20590-0001.
     Fax: (202) 493-2251.
     Hand Delivery: Room PL-401 on the plaza level of the 
Nassif Building, 400 Seventh Street, SW., 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 General Electric Company via GE-Aviation, Attn: Distributions, 111 
Merchant St., Room 230, Cincinnati, Ohio 45246, telephone (513) 552-
3272; fax (513) 552-3329.
    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: Karen Curtis, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803; telephone (781) 238-
7192; 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-2006-24145; 
Directorate Identifier 2006-NE-06-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 DOT Docket Office

[[Page 16247]]

between 9 a.m. and 5 p.m., Monday through Friday, except Federal 
holidays. The Docket Office (telephone (800) 647-5227) is located on 
the plaza level of the Department of Transportation Nassif Building at 
the street address stated in ADDRESSES. Comments will be available in 
the AD docket shortly after the Docket Management Facility receives 
them.

Discussion

    Since 1975, 45 events of forward and aft center bodies separating 
from the engine have been reported. GE's investigation of the earlier 
events identified nut plate corrosion, and loose and missing fasteners 
as causes for the center body separations. In 1987, GE issued Service 
Bulletin (SB) No. CF6-50 S/B 78-216 to inspect for these conditions and 
add improved fasteners. In 2001, GE issued a Fleet Highlight and an All 
Operators Wire to remind operators of the availability of SB No. CF6-50 
S/B 78-216. In 2003, GE issued SB No. CF6-50 S/B 78-241 for improved 
fastener torque.
    In 2000, two separation events occurred. Investigation by GE and 
the FAA determined that bird strikes or other similar events can result 
in high engine imbalance conditions. These conditions can result in 
high stress and movement at the joint between the forward and aft 
center bodies, degrading the structural integrity of the joint, and 
separating the center bodies from the engine.
    GE and the FAA determined that additional improvements are 
necessary to ensure structural integrity of the center body joints 
during high imbalance events. GE completed certification in 2004 of 
improved forward and aft center bodies. GE's improvement adds doublers, 
larger nuts and bolts, and higher strength corrosion resistant nut 
plates.
    This condition, if not corrected, could result in the forward and 
aft center body of the LFCEN assembly separating, leading to additional 
damage to the engine and airplane, possible damage to other airplanes, 
and to objects on the ground.

Relevant Service Information

    We have reviewed and approved the technical contents of GE SB No. 
CF6-50 S/B 78-0242, dated September 26, 2005, that identifies 
disassembly, inspection, rework, and reassembly procedures for the 
forward and aft center body, to add doublers, larger nuts and bolts, 
and higher strength corrosion resistant nut plates.

FAA's Determination and Requirements of the Proposed AD

    We 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 will require 
reworking the forward and aft center bodies to add doublers, larger 
nuts and bolts, and higher strength corrosion resistant nut plates. 
This rework is required the next time the forward center body and aft 
center body are removed from the engine after the effective date of 
this 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 238 CF6-45 and CF6-
50 series turbofan engines installed on airplanes of U.S. registry. We 
also estimate that it would take about 22 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 $6,000 per engine. Based 
on these figures, we estimate the total cost of the proposed AD to U.S. 
operators to be $1,846,880.

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 
regulation:
    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. See the ADDRESSES section for a location 
to examine the regulatory evaluation.

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-2006-24145; Directorate 
Identifier 2006-NE-06-AD.

Comments Due Date

    (a) The Federal Aviation Administration (FAA) must receive 
comments on this airworthiness directive (AD) action by May 30, 
2006.

Affected ADs

    (b) None.

Applicability

    (c) This AD applies to General Electric Company (GE) CF6-45A, 
CF6-45A2, CF6-50C, CF6-50C1, CF6-50C2, CF6-50C2B, CF6-50C2D, CF6-
50E, CF6-50E1, CF6-50E2, and CF6-50E2B series turbofan engines with 
long fixed core exhaust nozzle (LFCEN) assembly forward center body, 
part number (P/N) 1313M55G01 or G02, P/N 9076M28G09 or G10, and aft 
center body P/N 1313M56G01 or 9076M46G05, installed. These engines 
are installed on, but not limited to, Airbus A300 series, Boeing 747 
series, McDonnell Douglas DC-10 series, and DC-10-30F (KC-10A, KDC-
10) airplanes.

Unsafe Condition

    (d) This AD results from reports of separation of LFCEN assembly 
forward and

[[Page 16248]]

aft center bodies, due to high imbalance engine conditions during 
flight. We are issuing this AD to prevent the forward and aft center 
body of the LFCEN assembly from separating, leading to additional 
damage to the engine and airplane, possible damage to other 
airplanes, and to objects on the ground.

Compliance

    (e) You are responsible for having the actions required by this 
AD performed the next time the forward and aft center bodies are 
removed from the engine after the effective date of this AD, unless 
the actions have already been done.
    (f) Rework the forward and aft center bodies to add doublers, 
larger nuts and bolts, and higher strength corrosion resistant nut 
plates. Use paragraph 3, Accomplishment Instructions, of GE Service 
Bulletin No. CF6-50 S/B 78-0242, dated September 26, 2005, to 
identify the procedures required to do these actions.

Definition

    (g) For the purposes of this AD, ``next time the forward and aft 
center bodies are removed from the engine'' includes when the center 
bodies are removed from the engine to take the engine off-wing.

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.

    Issued in Burlington, Massachusetts, on March 27, 2006.
Peter A. White,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. E6-4702 Filed 3-30-06; 8:45 am]
BILLING CODE 4910-13-P