[Federal Register Volume 64, Number 187 (Tuesday, September 28, 1999)]
[Proposed Rules]
[Pages 52259-52260]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-25122]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 99-NE-39-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, on certain engines
identified by serial numbers, a one-time visual inspection of Stage 2
high pressure turbine (HPT) aft cooling plates, for nicks, dents, and
scratches, and if present, dimensional inspection of indentation depth,
repair if indentation is within acceptable limits, and, if necessary,
replacement with serviceable parts. This AD would also require
inspection of the Stage 2 HPT rotor disk post aft surface which mates
with the Stage 2 HPT aft cooling plate, for raised metal and removal of
the raised metal, if present. This proposal is prompted by reports of
dented Stage 2 HPT aft cooling plates which occurred during the
assembly of the cooling plate to the Stage 2 disk due to raised metal
on the stage 2 HPT disk post aft mating surface. The actions specified
by the proposed AD are intended to prevent aft HPT cooling plate
failure, which could result in an uncontained engine failure and damage
to the airplane.
DATES: Comments must be received by November 29, 1999.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Regional
Counsel, Attention: Rules Docket No. 99-NE-39-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, MS 64-03/2101-201, P.O.
Box 52170, Phoenix, AZ 85972-2170; 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 99-NE-39-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. 99-NE-39-AD, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
The Federal Aviation Administration (FAA) has received reports of
certain Stage 2 high pressure turbine (HPT) aft cooling plates,
installed on CFE Company Model CFE738-1-1B turbofan engines, that were
dented during the assembly of the cooling plate to the stage 2 disk due
to raised metal on the aft mating face of the Stage 2 HPT rotor disk
post. During the assembly of the high-pressure turbine rotor, the Stage
2 disk is restrained with a special tool fixture. It has been
determined that a condition occurring in this fixture as early as
January 1998, may have resulted in raised metal on the disk post aft
surface, which interfaces with the aft cooling plate. The higher the
raised metal on the disk post, the deeper the dent in the cooling
plate. The fixture has been repaired to prevent further occurrences and
engines which may be effected by this condition have been identified by
serial numbers. Analysis indicates that nicks, dents, and scratches on
the Stage 2 HPT aft cooling plate exceeding a certain depth would
result in a reduction in part cyclic life. This condition, if not
corrected, could result in aft HPT cooling plate failure, which could
result in an uncontained engine failure and damage to the airplane.
Service Information
The FAA has reviewed and approved the technical contents of CFE
Alert
[[Page 52260]]
Service Bulletin (ASB) CFE738-A72-8031, Revision 1, dated June 23,
1999, that describes the dimensional inspection procedures for
indentation depth on aft HPT cooling plates, inspection of the stage 2
HPT rotor disk for raised metal, and the acceptance and repair criteria
of the Stage 2 HPT aft cooling plate and HPT rotor disk.
Proposed Actions
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, on engines identified by S/N, a one-time
visual inspection of Stage 2 high pressure turbine (HPT) aft cooling
plates for nicks, dents, and scratches, and if present, dimensional
inspection of indentation depth, repair if indentation is within
acceptable limits, and, if necessary, replacement with serviceable
parts. This AD would also require inspection of the Stage 2 HPT rotor
disk post aft surface which mates with the Stage 2 HPT aft cooling
plate, for raised metal, and, removal of the raised metal, if present.
The inspections would be required at the next shop visit after the
effective date of this AD where the HPT assembly is sufficiently
disassembled to afford access to the Stage 2 HPT aft cooling plate, but
not later than 4,500 part cycles since new (CSN) in accordance with the
ASB described previously.
Economic Analysis
There are approximately 72 engines of the affected design in the
worldwide fleet. The FAA estimates that 48 engines installed on
aircraft of US registry would be affected by this proposed AD, that it
would take approximately 4 work hours per engine to accomplish the
proposed inspection if the inspection did not take place during
scheduled maintenance, and that the average labor rate is $60 per work
hour. Required parts would cost approximately $1,536 per engine. Based
on these figures, the total cost impact of the proposed AD on US
operators is estimated to be $106,560.
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:
Company: Docket No. 99-NE-39-AD.
Applicability: CFE Model CFE738-1-1B turbofan engines, serial
numbers (S/Ns) 105267 through 105339, inclusive. These engines are
installed on but not limited to Dassault-Breguet Falcon 2000 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 (b) 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.
(a) At the next engine shop visit after the effective date of
this AD where the HPT assembly is sufficiently disassembled to
afford access to the Stage 2 HPT aft cooling plate, but not later
than 4500 part cycles-since-new (CSN), accomplish the following in
accordance with CFE Alert Service Bulletin (ASB) No. CFE738-A72-
8031, Revision 1, dated June 23, 1999 as follows:
(1) Inspect the stage 2 HPT aft cooling plate for nicks, dents,
and scratches on surface D in accordance with the requirements of
ASB No. CFE738-A72-8031 paragraph 2.B.(1).
(2) Repair those stage 2 HPT aft cooling plates with indentation
less than 0.003 inch deep in accordance with ASB No. CFE738-A72-8031
paragraph 2.B.(1).
(3) Remove from service prior to further flight those stage 2
HPT aft cooling plates which have nicks, dents, and/or scratches
that exceed the acceptance limits in accordance with ASB No. CFE738-
A72-8031 paragraph 2.B.(1), and replace with a serviceable part.
(4) Inspect the stage 2 HPT rotor disk post aft mating surface
for raised metal, and remove raised metal if present in accordance
with ASB No. CFE738-A72-8031 section 2.B.(2).
(b) 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 request 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.
(c) 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 airplane to a location where
the inspection requirements of this AD can be accomplished.
Issued in Burlington, Massachusetts, on September 20, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 99-25122 Filed 9-27-99; 8:45 am]
BILLING CODE 4910-13-U
