[Federal Register Volume 67, Number 249 (Friday, December 27, 2002)]
[Proposed Rules]
[Pages 79007-79008]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 02-32659]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2002-NE-35-AD]
RIN 2120-AA64


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

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: The Federal Aviation Administration (FAA) proposes to adopt a 
new airworthiness directive (AD) that is applicable to General Electric 
Company (GE) CF6-50 series turbofan engines. This proposal would 
require removal from service of eight serial number (SN) low pressure 
turbine (LPT) stage 1 disks, part number (P/N) 9061M21P03, at the next 
engine shop visit. This proposal is prompted by a report of the 
potential for iron-rich inclusions introduced during manufacture in the 
affected disks. The actions specified by the proposed AD are intended 
to prevent LPT stage 1 disk cracking, due to iron-rich inclusions 
introduced during manufacture, leading to uncontained disk failure.

DATES: Comments must be received by February 25, 2003.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 2002-NE-35-AD, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location, by appointment, between 8 a.m. and 4:30 p.m., Monday 
through Friday, except Federal holidays. Comments may also be sent via 
the Internet using the following address: ``[email protected]''. 
Comments sent via the Internet must contain the docket number in the 
subject line.

FOR FURTHER INFORMATION CONTACT: Karen Curtis, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone: (781) 
238-7192, fax: (781) 238-7199.

SUPPLEMENTARY INFORMATION:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed rule by submitting such written data, views, or arguments as 
they may desire. Communications should identify the Rules Docket number 
and be submitted in triplicate to the address specified above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this action may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed rule. All 
comments submitted will be available, both before and after the closing 
date for comments, in the Rules Docket for examination by interested 
persons. A report summarizing each FAA-public contact concerned with 
the substance of this proposal will be filed in the Rules Docket.
    Commenters wishing the FAA to acknowledge receipt of their comments 
submitted in response to this action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2002-NE-35-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Regional Counsel, 
Attention: Rules Docket No. 2002-NE-35-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    In November of 2000, the FAA became aware that a CF6-80C2 engine 
high pressure turbine disk was rejected at inspection because it was 
cracked. GE and the disk supplier investigated and determined that the 
crack resulted from the presence of an iron-rich inclusion that was 
inadvertently introduced into the lot of INCO 718 disk material during 
the manufacturing melt process. GE and the disk supplier have since 
identified another lot that potentially had iron-rich inclusions 
introduced during the manufacturing melt process. That lot was used to 
manufacture eight CF6-50 engine LPT stage 1 disks. GE and the disk 
supplier have since coordinated and implemented corrective actions to 
prevent inclusions from being introduced in the manufacturing melt 
process.
    On November 30, 2001, GE issued service bulletin (SB) SB 72-1225, 
requesting that operators remove the eight suspect disks from service 
at the next engine shop visit. On January 7, 2002, GE issued All 
Operators Wire No. 02.CF6/002, again informing the operators of the 
above SB, recommending removal of the suspect disks from service, and 
requesting report back of the disk removal date to GE. Currently, not 
all of the eight disks have been reported as having been removed or 
scheduled for removal. This condition, if not corrected, could result 
in LPT stage 1 disk cracking, leading to uncontained disk failure.

FAA's Determination of an Unsafe Condition and Proposed Actions

    Since an unsafe condition has been identified that is likely to 
exist or develop on other CF6 series turbofan engines of a similar type 
design and manufacturing sequence, the proposed AD would require 
removal from service

[[Page 79008]]

of CF6-50 LPT stage 1 disks, P/N 9061M21P03, SN's SNL17693, SNL17694, 
SNL44200, SNL47624, SNL47625, SNL47626, SNL47627, and SNL47628 at the 
next engine shop visit after the effective date of the AD.

Economic Analysis

    There are approximately 2,101 CF6-50 series turbofan engines of the 
affected design in the worldwide fleet. The FAA estimates that no more 
than eight of the 469 engines installed on airplanes of U.S. registry 
would be affected by this proposed AD. The FAA also estimates that it 
would take approximately 32 work hours per engine to perform the 
proposed actions, and that the average labor rate is $60 per work hour. 
Required parts would cost approximately $75,490 per engine. Based on 
these figures, the total cost of the proposed AD to eight U.S. 
operators is estimated to be $619,280.

Regulatory Analysis

    This proposed rule does not have federalism implications, as 
defined in Executive Order 13132, because it 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. 
Accordingly, the FAA has not consulted with state authorities prior to 
publication of this proposed rule.
    For the reasons discussed above, I certify that this 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) if promulgated, 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. A copy of the draft 
regulatory evaluation prepared for this action is contained in the 
Rules Docket. A copy of it may be obtained by contacting the Rules 
Docket at the location provided under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
part 39 of the Federal Aviation Regulations (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.


39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

General Electric Company: Docket No. 2002-NE-35-AD.

Applicability

    This airworthiness directive (AD) is applicable to General 
Electric Company CF6-50 series turbofan engines with low pressure 
turbine (LPT) stage 1 disks, part number (P/N) 9061M21P03, serial 
numbers (SN's) SNL17693, SNL17694, SNL44200, SNL47624, SNL47625, 
SNL47626, SNL47627, and SNL47628 installed. These engines are 
installed on, but not limited to Airbus Industrie A300, Boeing 747, 
and McDonnell Douglas DC-10 airplanes.

    Note 1: This AD applies to each engine identified in the 
preceding applicability provision, regardless of whether it has been 
modified, altered, or repaired in the area subject to the 
requirements of this AD. For engines that have been modified, 
altered, or repaired so that the performance of the requirements of 
this AD is affected, the owner/operator must request approval for an 
alternative method of compliance in accordance with paragraph (c) of 
this AD. The request should include an assessment of the effect of 
the modification, alteration, or repair on the unsafe condition 
addressed by this AD; and, if the unsafe condition has not been 
eliminated, the request should include specific proposed actions to 
address it.

Compliance

    Compliance with this AD is required as indicated, unless already 
done.
    To prevent LPT stage 1 disk cracking due to the potential for 
iron-rich inclusions introduced during manufacture, leading to 
uncontained disk failure, do the following:
    (a) Remove from service LPT stage 1 disks P/N 9061M21P03, SN's 
SNL17693, SNL17694, SNL44200, SNL47624, SNL47625, SNL47626, 
SNL47627, and SNL47628 at the next engine shop visit.
    (b) After the effective date of this AD, do not install any of 
the LPT stage 1 disks listed in paragraph (a) of this AD into any 
engine.

Alternative Methods of Compliance

    (c) An alternative method of compliance or adjustment of the 
compliance time that provides an acceptable level of safety may be 
used if approved by the Manager, Engine Certification Office (ECO). 
Operators must submit their request through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Special Flight Permits

    (d) Special flight permits may be issued in accordance with 
Sec. Sec.  21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be done.

    Issued in Burlington, Massachusetts, on December 20, 2002.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 02-32659 Filed 12-26-02; 8:45 am]
BILLING CODE 4910-13-P