[Federal Register Volume 64, Number 184 (Thursday, September 23, 1999)]
[Proposed Rules]
[Pages 51484-51486]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-24787]
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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: Supplemental notice of proposed rulemaking; reopening of
comment period.
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SUMMARY: This notice revises an earlier proposed airworthiness
directive (AD), applicable to CFE Company model CFE738-1-1B turbofan
engines, that would have required a one-time dimensional inspection of
the curvic coupling tooth profile of certain high pressure compressor
(HPC) rotor
[[Page 51485]]
components to check for machining mismatches in the curvic coupling in
specific engines and, if necessary, replacement with serviceable parts.
That proposal was prompted by reports of machining mismatches in
certain HPC rotor components that may decrease the service life of
these HPC parts. This action, based on subsequent material stress
testing and analysis by CFE Company, revises the proposed rule by
eliminating the dimensional inspection requirement and imposing new,
reduced life limits for certain HPC rotor components in all engines.
The actions specified by this proposed AD are intended to prevent
failure of certain HPC rotor components, which could result in an
uncontained engine failure and damage to the airplane.
DATES: Comments must be received by November 22, 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: ``adcomment@faa.gov''. 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, PO
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
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to add an airworthiness directive (AD), applicable to CFE
Company model CFE738-1-1B turbofan engines, was published as a notice
of proposed rulemaking (NPRM) in the Federal Register on December 14,
1998 (63 FR 68707). That NPRM would have required a one-time
dimensional inspection of the curvic coupling tooth profile of certain
high pressure compressor (HPC) rotor components installed on specific
engines to check for machining mismatches in the curvic coupling, and,
if necessary, replacement with serviceable parts. That NPRM was
prompted by the determination that certain stage 4 and 5 blisks,
impeller aft shafts, and impellers in specified engines may have
machining mismatches in the curvic coupling tooth profiles. That
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 airplane.
Events Since Issuance of the NPRM
Since the issuance of that NPRM, additional material stress testing
indicates that the machining mismatch does not reduce cyclic life, as
previously predicted by analysis. Therefore, the requirement for
dimensional inspection of the curvic coupling tooth profile of the
stage 4 and 5 blisk, impeller, and impeller aft shaft to check for
machining mismatch can be removed. However, the additional testing
indicates that for certain 4th and 5th stage blisks and impeller aft
shafts the cyclic lives, for reasons not yet fully understood, are
below previously predicted cyclic lives, independent of the presence of
curvic coupling machining mismatches. Therefore, this proposal would
reduce the cyclic life limits on certain stage 4 and 5 blisks and the
impeller aft shafts.
Proposed Actions
This AD would require removal from service of certain stage 4 and 5
blisks and impeller aft shafts prior to exceeding new, reduced cyclic
life limits, and replacement with serviceable parts. No parts in
service at this time are near the reduced cyclic life limits. The
manufacturer anticipates that the reduced limits may be increased based
upon further testing and analysis.
Since this change expands the scope of the originally proposed
rule, the FAA has determined that it is necessary to reopen the comment
period to provide additional opportunity for public comment.
Economic Analysis
There are approximately 245 engines of the affected design in the
worldwide fleet. The FAA estimates that 156 engines would be affected
by this proposed AD, that it would take approximately 10 work hours per
engine if performed at a scheduled inspection, and 450 work hours if
not performed at a scheduled inspection (applicable for 2 engines
only). The average labor rate is $60 per work hour. Required parts, on
a pro-rated basis, would cost approximately $13,613 per engine. Based
on these figures, the total cost impact of the proposed AD on US
operators is estimated to be $2,159,665.
Regulatory Impact
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.
[[Page 51486]]
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,
installed on but not limited to the Dassault Aviation Falcon 2000
series airplanes.
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) Remove from service certain stage 4 and 5 blisks and
impeller aft shafts prior to exceeding the new reduced cyclic life
limits as follows, and replace with serviceable parts:
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Cyclic
Life
Limit
Nomenclature Part No. (P/N) (cycles
since
new)
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Stage 4 and 5 Blisk................ 6079T74P07 2,370
6079T74P08 3,450
6079T74P09 3,790
Impeller Aft Shaft................. 6079T80P04 5,100
6079T80P05 2,160
6079T80P06 7,100
6079T80P07 7,100
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(b) Except for the provisions of paragraph (c) of this AD, no
parts, identified by P/N in paragraph (a) of this AD, may be
installed that exceed the new life limits.
(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 (ECO).
Operators shall submit their requests through an appropriate FAA
Principal Maintenance Inspector, who may add comments and then send
it to the Manager, ECO.
Note 2: Information concerning the existence of approved
alternative methods of compliance with this airworthiness directive,
if any, may be obtained from the ECO.
Issued in Burlington, Massachusetts, on September 16, 1999.
Donald E. Plouffe,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-24787 Filed 9-22-99; 8:45 am]
BILLING CODE 4910-13-P
