[Federal Register Volume 63, Number 60 (Monday, March 30, 1998)]
[Rules and Regulations]
[Pages 15073-15075]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-7560]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 98-ANE-16-AD; Amendment 39-10420; AD 98-07-02]
RIN 2120-AA64
Airworthiness Directives; CFM International CFM56-2, -3, -3B, and
-3C Series Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment adopts a new airworthiness directive (AD) that
is applicable to CFM International CFM56-2, -3, -3B, and -3C series
turbofan engines. This action requires the removal from service of
certain No. 3 bearing rear stationary air/oil seals, replacement with
serviceable parts, and the installation of retention bushings. This
action also requires the removal from service of high pressure
compressor rotor (HPCR) stage 1-2 spools that have contacted the outer
cone of the seal. This amendment is prompted by several reports of
outer cone separation of the No. 3 bearing rear stationary air/oil
seal. The actions specified in this AD are intended to prevent rubs
between the outer cone of the No. 3 bearing rear stationary air/oil
seal and the HPCR stage 1-2 spool, which could result in a potential
uncontained failure of the HPCR stage 1-2 spool, and damage to the
aircraft.
DATES: Effective March 30, 1998.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of March 30, 1998.
Comments for inclusion in the Rules Docket must be received on or
before May 29, 1998.
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-16-AD, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may also be sent
via the Internet using the following address: ``engineprop@faa.dot.gov''. Comments sent via the Internet must contain
the docket number in the subject line.
The service information referenced in this AD may be obtained from
CFM International, Technical Publications Department, 1 Neumann Way,
Cincinnati, OH 45215; telephone (513) 552-2981, fax (513) 552-2816.
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: Robert Ganley, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (781)
238-7138; fax (781) 238-7199.
SUPPLEMENTARY INFORMATION: The Federal Aviation Administration (FAA)
has received 26 reports where the inner and outer cones of the No. 3
bearing rear stationary air/oil seal have separated on CFM
International CFM56-2, -3, -3B, and -3C series turbofan engines. The
seal consists of two composite cones which are bonded together with an
adhesive. Investigation revealed that the adhesive used on certain
seals have less bonding capability than required. When the seal
debonds, the outer cone moves aft and allows oil to migrate into the
high pressure compressor rotor (HPCR) flowpath, which may result in oil
fumes in the cabin. As the seal continues to move aft, the outer cone
contacts the bore of the stage 1 disk of the HPCR stage 1-2 spool. New
retention bushings exist, that when installed, will preclude a
separated seal from contacting the HPCR stage 1-2 spool. This
condition, if not corrected, could result in rubs between the outer
cone of the No. 3 bearing rear stationary air/oil seal and the HPCR
stage 1-2 spool, which could result in a potential uncontained failure
of the HPCR stage 1-2 spool, and damage to the aircraft.
The FAA has reviewed and approved the technical contents of CFM
International CFM56-2 Service Bulletin (SB) No. 72-825 and CFM56-3/-3B/
-3C SB No. 72-856, both dated January 23, 1998, that describes
procedures for removal from service of certain HPCR stage 1-2 spools
from engines that have documented rubs on the stage 1 disk bore due to
contact with the outer cone of the No. 3 bearing rear stationary air/
oil seal. In addition, the FAA has reviewed and approved the technical
contents of CFM International CFM56-2 SB No. 72-823, dated August 12,
1997, and CFM56-3/-3B/-3C SB No. 72-855, Revision 1, dated February 9,
1998, that describes procedures for installation of the No. 3 bearing
rear stationary air/oil seal retention bushings.
Since an unsafe condition has been identified that is likely to
exist or develop on other engines of the same type design, this AD is
being issued to prevent rubs between the outer cone of the No. 3
bearing rear stationary air/oil seal and the HPCR stage 1-2 spool,
which could result in a potential uncontained failure of the HPCR stage
1-2 spool. This AD requires the removal from service, within 15 days
after the effective date of this AD, of certain No. 3 bearing rear
stationary air/oil seals, replacement with serviceable parts, and the
installation of retention bushings. This AD also requires the removal
from service of HPCR stage 1-2 spools that have contacted the outer
cone of the seal at the next engine shop visit after the effective date
of this AD, or prior to accumulating 2,000 cycles in service (CIS)
since the engine shop visit that first confirmed the rub event. The
2,000 CIS interval was established based on an extensive test program
on the CFM56-5 series engine. The compliance end-date was determined
based upon risk assessment and parts availability. The actions are
required to be accomplished in accordance with the SBs described
previously.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this rule by
submitting such written data, views, or
[[Page 15074]]
arguments as they may desire. Communications should identify the Rules
Docket number and be submitted in triplicate to the address specified
under the caption ADDRESSES. All communications received on or before
the closing date for comments will be considered, and this rule may be
amended in light of the comments received. Factual information that
supports the commenter's ideas and suggestions is extremely helpful in
evaluating the effectiveness of the AD action and determining whether
additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the 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 that
summarizes each FAA-public contact concerned with the substance of this
AD 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-16-AD.'' The postcard will be date stamped and
returned to the commenter.
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and is not a ``significant regulatory action''
under Executive Order 12866. It has been determined further that this
action involves an emergency regulation under DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979). If it is determined
that this emergency regulation otherwise would be significant under DOT
Regulatory Policies and Procedures, a final regulatory evaluation will
be prepared and placed in the Rules Docket. A copy of it, if filed, 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:
98-07-02 CFM International: Amendment 39-10420. Docket 98-ANE-16-
AD.
Applicability: CFM International CFM56-2, -3, -3B, and -3C
series turbofan engines installed on, but not limited to, McDonnell
Douglas DC-8 series and Boeing 737 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 (e) 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 rubs between the outer cone of the No. 3 bearing rear
stationary air/oil seal and the high pressure compressor rotor
(HPCR) stage 1-2 spool, which could result in a potential
uncontained failure of the HPCR stage 1-2 spool, and damage to the
aircraft, accomplish the following:
(a) For CFM International CFM56-2 series engines, with high
pressure compressor rotor (HPCR) stage 1-2 spool, Part Number (P/N)
9992M60G07, with part Serial Number (S/N) listed in CFM56-2 Service
Bulletin (SB) No. 72-825, dated January 23, 1998, installed,
accomplish the following:
(1) Remove the HPCR stage 1-2 spool from service at the next
engine shop visit after the effective date of this AD, or prior to
accumulating 2,000 cycles in service (CIS) since the engine shop
visit that first confirmed the rub event, whichever occurs first, in
accordance with CFM International CFM56-2 SB No. 72-825, dated
January 23, 1998, and replace with a serviceable HPCR stage 1-2
spool.
(2) Install No. 3 bearing rear air/oil seal retention bushings
in accordance with CFM International CFM56-2 SB No. 72-823, dated
August 12, 1997.
(b) For CFM International CFM56-3, -3B, and -3C series engines,
with HPCR stage 1-2 spool, P/N 1589M66G02, with part S/Ns listed in
CFM International CFM56-3/-3B/-3C SB No. 72-856, dated January 23,
1998, installed, accomplish the following:
(1) Remove the HPCR stage 1-2 spool from service at the next
engine shop visit after the effective date of this AD, or prior to
accumulating 2,000 CIS since the engine shop visit that first
confirmed the rub event, whichever occurs first, in accordance with
CFM56-3/-3B/-3C SB No. 72-856, dated January 23, 1998, and replace
with a serviceable HPCR stage 1-2 spool.
(2) Install No. 3 bearing rear air/oil seal retention bushings
in accordance with CFM International CFM56-3/-3B/-3C SB No. 72-855,
Revision 1, dated February 9, 1998.
(c) For CFM56-3, -3B, and -3C engines, having any of the
following engine S/Ns: 856692, 856709, 856713, 856799, 856673,
856691, 856694, 856696, 856697, 856746, 856780, 857669, 857685,
857686, 857704, and 859115; accomplish the following within 15 days
after the effective date of this AD:
(1) Remove from service No. 3 bearing rear stationary air/oil
seal, P/N 1663M91G03, and replace with a serviceable No. 3 bearing
rear stationary air/oil seal. No. 3 bearing rear stationary air/oil
seals removed in accordance with this paragraph are unserviceable.
(2) Install No. 3 bearing rear air/oil seal retention bushings
in accordance with CFM International CFM56-3/-3B/-3C SB No. 72-855,
Revision 1, dated February 9, 1998.
(d) For the purpose of this AD, the following definitions apply:
(1) A shop visit is defined as the induction of an engine into
the shop for any maintenance.
(2) A serviceable HPCR stage 1-2 spool is defined as a spool
without a rub or scratch indication.
(3) A serviceable No. 3 bearing rear stationary air/oil seal is
defined as a new seal, P/N 1663M91G03, that is not identified by S/N
in Table 1 of this AD.
Table 1.--No. 3 Bearing Rear Stationary Air/Oil Seal S/Ns
[P/N 1663M91G03]
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CTD81631 CTD81907 CTD81908 CTD81998
CTD82004 CTD82132 CTD82208 CTD82210
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CTD82212 CTD82213 CTD82271 CTD82295
CTD82297 CTD82298 CTD82300 CTD82304
CTD82457 CTD82759 CTD82766 CTD82767
CTD82788 CTD82817 CTD82822 CTD82854
CTD82855 CTD82856 CTD82857 CTD82859
CTD82962 CTD83232 CTD83474 CTD83837
CTD83839 CTD84100 CTD84138 CTD84140
CTD84141 CTD84143 CTD84144 CTD84145
CTD84148 CTD84203 CTD84206 CTD84207
CTD84258 CTD84262 CTD84360 CTD84363
CTD84604 CTD84712 CTD84741 CTD85147
CTD85148 CTD85149 CTD85161 CTD85162
CTD85166 CTD85168 CTD85169 CTD85170
CTD85172 CTD85348 CTD85349 CTD85351
CTD85352 CTD85353 CTD85354 CTD85355
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(e) 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 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.
(f) 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.
(g) The actions required by this AD shall be done in accordance
with the following CFM International SBs:
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Document No. Pages Revision Date
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CFM56-2, SB No. 72-823........... 1-12 Original................. August 12, 1997.
Total pages: 12.
CFM56-2, SB No. 72-825........... 1-7 Original................. January 23, 1998.
Total pages: 7.
CFM56-3/-3B/-3C, SB No. 72-856... 1-8 Original................. January 23, 1998.
Total pages: 8.
CFM56-3/-3B/-3C, SB No. 72-855... 1-16 1........................ February 9, 1998.
Total pages: 16.
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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 CFM International, Technical
Publications Department, 1 Neumann Way, Cincinnati, OH 45215;
telephone (513) 552-2981, fax (513) 552-2816. Copies may be
inspected at the FAA, New England Region, Office of 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.
(h) This amendment becomes effective on March 30, 1998.
Issued in Burlington, Massachusetts, on March 17, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 98-7560 Filed 3-27-98; 8:45 am]
BILLING CODE 4910-13-P
