[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: ``9-ad-
[email protected]''. 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        

[[Page 15075]]

                                                                        
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:

----------------------------------------------------------------------------------------------------------------
           Document No.                   Pages                 Revision                       Date             
----------------------------------------------------------------------------------------------------------------
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