[Federal Register Volume 63, Number 239 (Monday, December 14, 1998)]
[Proposed Rules]
[Pages 68707-68708]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-33026]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-69-AD]
RIN 2120-AA64
Airworthiness Directives; CFE Company Model CFE738-1-1B 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 CFE Company model CFE738-1-1B
turbofan engines. This proposal would require a one-time dimensional
inspection of the curvic coupling tooth profile of certain high
pressure compressor (HPC) rotor components to check for machining
mismatches in the curvic coupling, and, if necessary, replacement with
serviceable parts. The actions specified by the proposed AD are
intended to prevent failure of certain HPC rotor components, which
could result in an uncontained engine failure and damage to the
aircraft.
DATES: Comments must be received by February 12, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Regional
Counsel, Attention: Rules Docket No. 98-ANE-69-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``9-ad-
[email protected]''. Comments sent via the Internet must contain the
docket number in the subject line. 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 CFE Company, Data Distribution, M/S 64-03/2101-201, P. O.
Box 52170, Phoenix, AZ 85072-2170; telephone (602) 365-2493, fax (602)
365-5577. This information may be examined at the FAA, New England
Region, Office of the Regional Counsel, 12 New England Executive Park,
Burlington, MA.
FOR FURTHER INFORMATION CONTACT: Keith Mead, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7744, fax (781) 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 98-ANE-69-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 Regional Counsel,
Attention: Rules Docket No. 98-ANE-69-AD, 12 New England Executive
Park, Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) has determined that
certain stage 4 and 5 high pressure compressor (HPC) blisks, the
impeller aft shafts, and the impellers, installed on CFE Company model
CFE738-1-1B turbofan engines, have machining mismatches in the curvic
coupling tooth profiles, including under-minimum root fillet radii,
tooth profile mismatch and gable mismatch. These machining mismatches,
if present, may decrease the service life of these HPC parts. This
condition, if not corrected, could result in failure of certain HPC
rotor components, which could result in an uncontained engine failure
and damage to the aircraft.
[[Page 68708]]
The FAA has reviewed and approved the technical contents of CFE
Company Alert Service Bulletin (ASB) No. CFE738-A72-8029, dated October
1, 1998, that describes procedures for dimensional inspections of
curvic couplings on certain HPC rotor 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 a one-time dimensional inspection of the
curvic coupling tooth profile of certain HPC rotor components to check
for machining mismatches in the curvic coupling, and, if necessary,
replacement with serviceable parts. The actions would be required to be
accomplished in accordance with the ASB described previously.
There are approximately 146 engines of the affected design in the
worldwide fleet. The FAA estimates that 94 engines installed on
aircraft of U.S. registry would be affected by this proposed AD, that
it would take approximately 300 work hours per engine to accomplish the
proposed actions, and that the average labor rate is $60 per work hour.
Required parts would cost approximately $18,000 per engine. Based on
these figures, the total cost impact of the proposed AD on U.S.
operators is estimated to be $3,384,000.
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:
CFE Company: Docket No. 98-ANE-69-AD.
Applicability: CFE Company Model CFE738-1-1B turbofan engines,
serial numbers 105106 through 105251, installed on but not limited
to the Dassault Aviation Falcon 2000 model 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 failure of certain high pressure compressor (HPC)
rotor components, which could result in an uncontained engine
failure and damage to the airplane, accomplish the following:
(a) Perform a one-time dimensional inspection of the curvic
coupling tooth profile of certain HPC components, as identified in
the table below, for machining mismatches in the curvic coupling,
prior to exceeding the specified number of cycles since new, as
listed in the table below, in accordance with procedures described
in CFE Company Alert Service Bulletin (ASB) CFE738-A72-8029, dated
October 1, 1998:
------------------------------------------------------------------------
Cycles
Nomenclature Part No. since
new
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Stage 4 and 5 Blisk.................. 6079T74P07 2,460
6079T74P08 3,430
Impeller Shaft....................... 6079T80P05 1,670
6079T80P04 2,060
Impeller............................. 6079T77P05 2,150
6079T77P06 2,130
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(b) Remove from service any component that is found with a
machining mismatch, and replace with serviceable component. 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 request through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, Engine Certification Office.
Note 2: 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 December 7, 1998.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 98-33026 Filed 12-11-98; 8:45 am]
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