[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