[Federal Register: January 8, 2003 (Volume 68, Number 5)]
[Proposed Rules]
[Page 1016-1017]
From the Federal Register Online via GPO Access [wais.access.gpo.gov]
[DOCID:fr08ja03-9]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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[[Page 1016]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 2002-NE-24-AD]
RIN 2120-AA64
Airworthiness Directives; General Electric Company CF6-6 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
(GE) CF6-6 series turbofan engines. This proposal would require a
reduction of the cyclic life limit for certain high pressure turbine
rotor (HPTR) rear shafts, and would require removing certain HPTR rear
shafts from service before exceeding the new, lower cyclic life limit.
In addition, the proposal would require removing from service certain
HPTR rear shafts that currently exceed, or will exceed, the new, lower
cyclic life limit according to the compliance schedule described in
this proposal. The actions specified by the proposed AD are intended to
prevent cracks in HPTR rear shafts that could result in uncontained
engine failure and damage to the airplane.
DATES: Comments must be received by March 10, 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-24-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: ``9-ane-adcomment@faa.gov''.
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, e-mail: karen.curtis@faa.gov.
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-24-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-24-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
An updated low-cycle fatigue (LCF) analysis of certain HPTR rear
shaft part numbers installed in CF6-6 engines, including an improved 3D
finite element analysis of certain features, was performed by the
manufacturer. That analysis indicated the need to lower the cyclic life
limit for these part numbers. The updated analysis was prompted by a
recently completed analysis on the same rotor assembly, but with
different blades.
This proposal will require a new life limit for these HPTR rear
shaft P/N's of 8,950 cycles-since-new. On August 8, 2002, the
manufacturer issued Temporary Revision TR 05-0022, revising the life
limits section of the engine manual to reflect the new life limit for
these shafts. Because the fleet contains rear shafts that exceed this
new lower limit, a draw down plan is required. This condition, if not
corrected could result in LCF cracking and failure of the shafts, which
could result in uncontained engine failure and damage to the airplane.
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 GE CF6-6 series turbofan engines of the same
type design, the proposed AD would establish a new, lower cyclic life
limit of 8,950 CSN for HPTR rear shafts P/N's 9137M13G01/G02/G03,
9138M22G01/G02/G09/G10, 9138M25G02, and 9687M22G04/G07/G10 and would
require removing certain HPTR rear shafts from service before exceeding
the new, lower cyclic life limit. In addition, the proposal would
require removing from service certain HPTR rear shafts that currently
exceed, or will exceed, the new, lower cycle life limit according to a
compliance schedule based on accumulated cycles on the rear shaft on
the effective date of this AD.
Economic Analysis
There are approximately 55 GE CF6-6 series turbofan engines of the
affected design in the domestic fleet that would be affected by this
proposed AD. There are no foreign registered engines. There are no
labor or parts costs associated with the implementation of this
proposed action. The total cost of the proposed AD to U.S. operators is
[[Page 1017]]
estimated to be $41,690 per engine, which is the cost of new rear
shafts.
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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
General Electric Company: Docket No. 2002-NE-24-AD.
Applicability
This airworthiness directive (AD) is applicable to General
Electric Company CF6-6 series turbofan engines. These engines are
installed on, but not limited to McDonnell Douglas DC-10 series
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 (e) 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 cracks in high pressure turbine rotor (HPTR) rear
shafts, which could result in uncontained engine failure and damage
to the airplane, do the following:
(a) Remove from service HPTR rear shafts, part numbers (P/N's)
9137M13G01/G02/G03, 9138M22G01/G02/G09/G10, 9138M25G02, and
9687M22G04/G07/G10 in accordance with Table 1 as follows:
Table 1.--HPTR Rear Shaft Removal Schedule
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If the rear shaft cycles-since-new
(CSN) on the effective date of this AD Then remove the rear shaft
are:
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(1) Fewer than 5,000 CSN............... Before exceeding 8,950 CSN
(2) 5,000 CSN or more, but fewer than Within 3,950 additional cycles-
8,950 CSN. in-service (CIS) from the
effective date of this AD or
before 11,550 CSN, whichever
occurs earlier.
(3) 8,950 CSN or more.................. At next HPTR rear shaft piece
part exposure, or within 2,600
additional cycles-in-service
(CIS), whichever occurs
earlier.
------------------------------------------------------------------------
(b) After the effective date of this AD, do not install any HPTR
rear shaft, P/N 9137M13G01/G02/G03, 9138M22G01/G02/G09/G10,
9138M25G02, or 9687M22G04/G07/G10, that has 8,950 or more CSN into
an engine.
(c) Except as provided in paragraph (a) of this AD, this action
establishes a new, cyclic life limit of 8,950 CSN for HPTR rear
shaft P/N's 9137M13G01/G02/G03, 9138M22G01/G02/G09/G10, 9138M25G02,
and 9687M22G04/G07/G10 which is published in Chapter 05-11-03 of
CF6-6 Engine Shop Manual, GEK 9266.
Definition
(d) For the purpose of this AD, HPTR rear shaft piece-part
exposure is defined as complete disassembly of the rear shaft from
the HPTR structure in accordance with the manufacturer's engine
manual.
Alternative Methods of Compliance
(e) 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
(f) Special flight permits may be issued in accordance
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 January 3, 2003.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 03-330 Filed 1-7-03; 8:45 am]
BILLING CODE 4910-13-P