[Federal Register Volume 62, Number 185 (Wednesday, September 24, 1997)]
[Proposed Rules]
[Pages 49945-49946]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-25312]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-28-AD]
RIN 2120-AA64
Airworthiness Directives; General Electric Company (GE) GE90-76B
Model Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
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SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to General Electric Company (GE)
GE90-76B model turbofan engines. This proposed AD would require reduced
life limits for certain rotating components installed in GE90-76B
engines. This proposal is prompted by the results of a refined life
analysis performed by the manufacturer which revealed minimum
calculated low cycle fatigue lives lower than the published low cycle
fatigue retirement lives for certain rotating components installed in
the GE90-76B engines. If not corrected, this condition could result in
a low cycle fatigue failure of a rotating component and possibly an
uncontained engine failure.
DATES: Comments must be received by November 24, 1997.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 97-ANE-28-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments also may be
submitted to the Rules Docket by using the following Internet address:
``[email protected]''. All comments must contain the Docket
No. in the subject line of the comment. Comments may be inspected at
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday,
except Federal holidays.
The service information referenced in the proposed rule may be
obtained from General Electric Company Technical Services, Attention:
Leader for distribution/microfilm, 10525 Chester Road, Cincinnati, OH
45215, telephone (513) 672-8400 Ext. 114, Fax (513) 672-8422. This
information may be examined at the FAA, New England Region, Office of
the Assistant Chief Counsel, 12 New England Executive Park, Burlington,
MA.
FOR FURTHER INFORMATION CONTACT: John Golinski, Aerospace Engineer,
Engine Certification Office, FAA, Engine & Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; Telephone (617)
238-7135, Fax (617) 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 notice 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 notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 97-ANE-28-AD.'' The postcard will be date stamped and
returned to the commenter.
Availability of NPRMs
Any person may obtain a copy of this NPRM by submitting a request
to the FAA, New England Region, Office of the Assistant Chief Counsel,
Attention: Rules Docket No. 97-ANE-28-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
As part of the substantiation for the Federal Aviation
Administration's (FAA) certification of the GE90-92B engine, GE
submitted an analysis to the
[[Page 49946]]
FAA defining the low cycle fatigue life of GE 90 rotating components.
The analysis included an updated material property data base and other
refinements that resulted in a reduction of the published low cycle
fatigue retirement life limit for certain rotating components. The FAA
has determined that this AD is necessary to mandate reduced life limits
for certain rotating components installed in GE90-76B engines. If not
corrected, this condition could result in a low cycle fatigue failure
of a rotating component and possibly an uncontained engine failure.
The FAA has reviewed and approved the technical contents of General
Electric Company GE90 Alert Service Bulletin (ASB) No. 72-A318, dated
June 27, 1997, that describes reduced life limits for certain rotating
components. Since an unsafe condition has been identified that is
likely to exist or develop on other products of this same type design,
the proposed AD would require reduced life limits for certain rotating
components. The actions would be required to be accomplished in
accordance with the ASB described previously.
There are approximately twenty-five engines of the affected design
in the worldwide fleet. The manufacturer has advised the FAA that there
are currently no engines installed on aircraft of U.S. registry that
would be affected by this proposed AD. Therefore, there is no
associated cost impact on U.S. operators as a result of this proposed
AD.
The FAA estimates that the most representative engines would have
four of the seven life-limited-reduced components installed. Assuming
the four components are the High Pressure Compressor Rotor (HPCR) 2-6
spool, HPCR stage 7 disk, HPCR CDP seal and the Low Pressure Turbine
cone shaft and that the parts cost is proportional to the reduction of
the low cycle fatigue retirement lives, the required parts would cost
approximately $189,123 per engine. Based on these figures, the FAA
estimates the total cost impact of this proposed AD would be $189,123
per engine.
The regulations proposed herein would not have substantial direct
effects 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. Therefore, in
accordance with Executive Order 12612, it is determined that this
proposal would not have sufficient federalism implications to warrant
the preparation of a Federalism Assessment.
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. 97-ANE-28-AD.
Applicability: General Electric Company (GE) GE90-76B model
turbofan engines installed on but not limited to Boeing 777
aircraft.
Note 1: This airworthiness directive (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: Required as indicated, unless accomplished
previously.
To prevent a low cycle fatigue failure of a rotating component
and possibly an uncontained engine failure, accomplish the
following:
(a) Remove from service those components listed in Table 1 of GE
Alert Service Bulletin (ASB) No. 72-A318, dated June 27, 1997, and
replace with a serviceable component, prior to exceeding the new
cyclic life limits established in paragraph (d) of ASB No. 72-A318,
dated June 27, 1997.
Note 2: These revised component life limits will be added to the
GE90 Engine Manual, Chapter 05-11-00, Life Limits 001 in the August
1, 1997, Revision.
(b) Except as provided in paragraph (c) of this AD, no
replacement times may be approved for these parts.
(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.
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Engine Certification Office.
Note 3: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the Engine Certification Office.
(d) Special flight permits may be issued in accordance with
sections 21.197 and 21.199 of the Federal Aviation Regulations (14
CFR 21.197 and 21.199) to operate the aircraft to a location where
the requirements of this AD can be accomplished.
Issued in Burlington, Massachusetts, on September 18, 1997.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 97-25312 Filed 9-23-97; 8:45 am]
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