[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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