[Federal Register Volume 63, Number 87 (Wednesday, May 6, 1998)]
[Rules and Regulations]
[Pages 24913-24914]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-11440]
[[Page 24913]]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-28-AD; Amendment 39-10496; AD 98-09-15]
RIN 2120-AA64
Airworthiness Directives; General Electric Company Model GE90-76B
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to General Electric Company (GE) Model GE90-76B turbofan
engines, that requires reduced life limits for certain rotating
components. This amendment 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. The actions
specified by this AD are intended to prevent a low cycle fatigue
failure of a rotating component and possibly an uncontained engine
failure.
DATES: Effective July 6, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of July 6, 1998.
ADDRESSES: The service information referenced in this AD 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 Regional Counsel, 12 New England Executive Park, Burlington, MA; or
at the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
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: A proposal to amend part 39 of the Federal
Aviation Regulations (14 CFR part 39) to include an airworthiness
directive (AD) that is applicable to General Electric Company (GE)
Model GE90-76B turbofan engines was published in the Federal Register
on September 24, 1997 (62 FR 49179). That action proposed to require
reduced life limits for certain rotating components.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comment received.
One commenter supports the rule as proposed.
Since publication of the Notice of Proposed Rulemaking (NPRM), GE
has provided the FAA with additional analysis that substantiates the
original cyclic life for the stage 7 disks (part numbers 350-000-656-0
and 350-000-657-0) of 10,000 cycles. These disks are exempted from this
AD based on recent FAA approval of GE's refined life analysis
substantiating the original cyclic life of 10,000 cycles for this
engine model. The latest revision of the GE90 Engine Manual, Chapter
05-11-00, Life Limits 001, restored the stage 7 disk lives for the
model to 10,000 cycles.
After careful review of the available data, including the comment
noted above, the FAA has determined that air safety and the public
interest require the adoption of the rule with the changes described
previously. The FAA has determined that these changes will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 24 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 AD. Therefore, there is no associated cost impact
on U.S. operators as a result of this AD.
The FAA estimates that the most representative engines will have 3
of the 6 life-limited-reduced components installed. Assuming the 3
components are the High Pressure Compressor Rotor (HPCR) 2-6 spool,
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 will cost approximately $181,993
per engine. Based on these figures, the FAA estimates that if an engine
were imported to the U.S., the total cost impact of this AD would be
$181,993 per engine.
The regulations adopted herein will 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 final
rule does not have sufficient federalism implications to warrant the
preparation of a Federalism Assessment.
For the reasons discussed above, I certify that this action (1) is
not a ``significant regulatory action'' under Executive Order 12866;
(2) is not a ``significant rule'' under DOT Regulatory Policies and
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action
and it is contained in the Rules Docket. A copy of it may be obtained
from the Rules Docket at the location provided under the caption
ADDRESSES.
List of Subjects in 14 CFR Part 39
Air transportation, Aircraft, Aviation safety, Incorporation by
reference, Safety.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 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:
98-09-15 General Electric Company: Amendment 39-10496. Docket No.
97-ANE-28-AD.
Applicability: General Electric Company (GE) GE90-76B Model
turbofan engines, installed on but not limited to Boeing 777 series
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 (d) 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.
[[Page 24914]]
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
GE90 Alert Service Bulletin (ASB) No. 72-A318, dated June 27, 1997,
(except as noted in paragraph (b) of this AD) and replace with a
serviceable component, prior to exceeding the new cyclic life limits
established in paragraph 1.D. (1) of GE90 ASB No. 72-A318, dated
June 27, 1997.
(b) GE has provided the FAA with additional analysis that
substantiates the original cycle life for the stage 7 disks (part
numbers 350-000-656-0 and 350-000-657-0) of 10,000 cycles. These
disks are exempted from this AD based on recent FAA approval of GE's
refined life analysis substantiating the original cycle life of
10,000 cycles for this engine model.
Note 2: The revised component life limits noted in GE90 ASB No.
72-A318, dated June 27, 1997, were added to the GE90 Engine Manual
Chapter 05-11-00, Life Limits 001, in the August 1, 1997, revision.
The latest revision of the GE90 Engine Manual, Chapter 05-11-00,
Life Limits 001, restored the stage 7 disk lives for the model to
10,000 cycles.
(c) Except as provided in paragraph (d) of this AD, no
replacement times may be approved for these parts.
(d) 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.
(e) 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.
(f) The actions required by this AD shall be done in accordance
with the following GE90 ASB:
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Document No. Pages Date
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72-A318............................ 1-5 June 27, 1997.
Total Pages: 5.
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This incorporation by reference was approved by the Director of
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR
part 51. Copies 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. Copies may be inspected at the FAA,
New England Region, Office of the Regional Counsel, 12 New England
Executive Park, Burlington, MA; or at the Office of the Federal
Register, 800 North Capitol Street NW., suite 700, Washington, DC.
(g) This amendment becomes effective on July 6, 1998.
Issued in Burlington, Massachusetts, on April 20, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 98-11440 Filed 5-5-98; 8:45 am]
BILLING CODE 4910-13-P
