[Federal Register Volume 62, Number 182 (Friday, September 19, 1997)]
[Proposed Rules]
[Pages 49177-49179]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-24909]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 89-ANE-05]
RIN 2120-AA64


Airworthiness Directives; CFM International CFM56-2, -3, -3B, -
3C, and -5 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This notice proposes the revision of an existing airworthiness 
directive (AD), applicable to CFM International (CFMI) CFM56-2, -3, -
3B, -3C, and -5 series turbofan engines, that currently requires 
repetitive magnetic chip detector (MCD) inspections and removal from 
service of certain No. 3 bearings. This action would remove the 
requirement for MCD inspections for certain No. 3 bearings if the 
bearing has 6,000 or more hours time in service since new, extend the 
removal from service date for certain No. 3 bearings, change the 
inspection interval for certain No. 3 bearings, delete a specific No. 3 
bearing part number, and replace reference to specific maintenance 
manuals with service bulletins. Other requirements of the current AD 
would remain unchanged and be carried over into the proposed AD. This 
proposal is prompted by additional data which demonstrates a reduced 
bearing failure rate after a period of time in service, therefore, an 
acceptable level of safety can be maintained with a relaxation of some 
of the current AD requirements. The actions specified by the proposed 
AD are intended to prevent a No. 3 bearing failure, and a subsequent 
inflight engine shutdown.

DATES: Comments must be received by November 18, 1997.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 89-ANE-05, 12 New England 
Executive Park, Burlington, MA 01803-5299. 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 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 Assistant Chief Counsel, 12 New England Executive 
Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Glorianne Messemer, Aerospace 
Engineer, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-5299; 
telephone (781) 238-7132, 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 89-ANE-05.'' 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 Assistant Chief Counsel, 
Attention: Rules Docket No. 89-ANE-05, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    On October 11, 1989, the Federal Aviation Administration (FAA) 
issued airworthiness directive (AD) 89-23-06, Amendment 39-6370 (54 FR 
43581, October 26, 1989), to require a repetitive inspection and 
removal from service program for certain No. 3 bearings installed on 
CFM International (CFMI) CFM56-2, -3, -3B, -3C, and -5 series turbofan 
engines. That action was prompted by a high rate of No. 3 bearing 
failures on CFM56 engines. That condition, if not corrected, could 
result in a No. 3 bearing failure, and a subsequent inflight engine 
shutdown.
    Since the issuance of AD 89-23-06, the FAA has received additional 
data concerning No. 3 bearing failures. This data demonstrates that the 
failure rate for No. 3 bearings with more than 6,000 hours time in 
service since new is significantly lower than for those with less than 
6,000 hours. Therefore, the FAA has determined that an acceptable level 
of safety will be maintained with a relaxation of some of the current 
AD requirements.
    In addition, since the issuance of AD 89-23-06, the manufacturer 
has also requested and obtained approval for an extension to the 
removal from service date for certain No. 3 bearings. The new date is 
December 31, 1997. Paragraphs (a)(2) and (b)(2) of the proposed rule 
reflect this new date.
    Also, since the issuance of AD 89-23-06, the manufacturer has 
obtained approval for a new inspection interval for CFM56-2 series 
engines. The new interval is 75 hours. Paragraph (d) of the proposed 
rule reflects this new interval.
    Further, since the issuance of AD 89-23-06, the manufacturer has 
advised the FAA that No. 3 bearing, Part Number (P/N) 1362M76P02, is 
not approved for CFM56-2 series engines. The manufacturer has confirmed 
that there are currently none in service, and have indicated that they 
do not plan to introduce any into service in the future. The 
manufacturer has therefore requested that this P/N be deleted from the 
AD. Paragraph (b) of the proposed rule omits this P/N.

[[Page 49178]]

    Finally, this proposal deletes reference to specific maintenance 
manuals. Since issuance of AD 89-23-06, the manufacturer has issued 
service bulletins (SBs) which outline all aspects of the No. 3 bearing 
inspection and replacement program.
    The FAA has reviewed and approved the technical contents of CFM56-2 
SB No. 72-620, Revision 4, dated November 17, 1995, CFM56-3/-3B/-3C SB 
No. 72-530, Revision 3, dated November 17, 1995, and CFM56-5 Alert 
Service Bulletin (ASB) No. 72-A118, Revision 1, dated August 1, 1997, 
that describe the No. 3 bearing inspection and replacement program.
    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 revise AD 89-23-06 to remove the requirement for MCD 
inspections for certain No. 3 bearings if the bearing has 6,000 or more 
hours time in service since new, extend the removal from service date 
for certain No. 3 bearings, change the inspection interval for certain 
No. 3 bearings, delete a specific No. 3 bearing P/N, and replace 
reference to specific maintenance manuals with service bulletins. Other 
requirements of the current AD would remain unchanged and be carried 
over into the proposed AD.
    All changes introduced in the proposed rule are relaxatory in 
nature except for the new inspection interval in paragraph (d). The 
manufacturer has advised the FAA that there is only one engine not 
installed on a U.S. registered aircraft that would be affected by this 
new inspection interval. Therefore, no additional cost to U.S. 
operators is expected to result from this proposed relaxatory action.
    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 ``major rule'' under Executive Order 12291; (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), 40101, 40113, 44701.


Sec. 39.13  [Amended]

    2. Section 39.13 is amended by removing Amendment 39-6370 (54 FR 
43581, October 26, 1989) and by adding the following new airworthiness 
directive (AD):

CFM International: Docket No. 89-ANE-05. Revises AD 89-23-06, 
Amendment 39-6370.

    Applicability: CFM International (CFMI) CFM56-2, -3, -3B, -3C, 
and -5 series turbofan engines, installed on but not limited to 
Airbus A319 and A320 series, 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 (h) 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 a No. 3 bearing failure and subsequent inflight 
engine shutdown, accomplish the following:
    (a) For CFM56-3, -3B, and -3C series engines equipped with No. 3 
bearings, Part Number (P/N) 9732M10P12 (Serial Number (S/N) series 
FAFDxxxx and FAFExxxx); 9732M10P18; or 1362M76P02 accomplish the 
following:
    (1) Inspect the forward sump magnetic chip detector (MCD) in 
accordance with CFM56-3/-3B/-3C Service Bulletin (SB) No. 72-530, 
Revision 3, dated November 17, 1995, within the next 50 hours time 
in service (TIS) after the effective date of this AD. Thereafter, 
inspect the forward sump MCD at intervals not to exceed 50 hours TIS 
since the last inspection (SLI) in accordance with CFM56-3/-3B/-3C 
SB No. 72-530, Revision 3, dated November 17, 1995, until 
accomplishment of paragraph (a)(2) of this AD, or, for bearing P/N 
9732M10P12, until the TIS since new is 6,000 hours or more. Remove 
from service, prior to further flight, engines which exhibit MCD 
metallic debris defined as not serviceable in accordance with CFM56-
3/-3B/-3C SB No. 72-530, Revision 3, dated November 17, 1995.
    (2) Remove from service affected No. 3 bearings at the next shop 
visit, or before December 31, 1997, whichever occurs first.
    (b) For CFM56-2 series engines equipped with No. 3 bearings, P/N 
9732M10P12 (S/N series FAFDxxxx and FAFExxxx) or 9732M10P18, 
accomplish the following:
    (1) Inspect the forward sump MCD in accordance with CFM56-2 SB 
No. 72-620, Revision 4, dated November 17, 1995, within the next 50 
hours TIS after the effective date of this AD. Thereafter, inspect 
the forward sump MCD at intervals not to exceed 50 hours TIS SLI in 
accordance with CFM56-2 SB No. 72-620, Revision 4, dated November 
17, 1995, until accomplishment of paragraph (b)(2) below, or, for 
bearing P/N 9732M10P12, until the TIS since new is 6,000 hours or 
more. Remove from service, prior to further flight, engines which 
exhibit MCD metallic debris defined as not serviceable in accordance 
with CFM56-2 SB No. 72-620, Revision 4, dated November 17, 1995.
    (2) Remove from service affected No. 3 bearings at the next 
engine shop visit, or before December 31, 1997, whichever occurs 
first.
    (c) For CFM56-3, -3B, and -3C series engines equipped with No. 3 
bearings, P/N 9732M10P10; 9732M10P17; or 9732M10P12 (S/N series 
other than FAFDxxxx or FAFExxxx), inspect the forward sump MCD in 
accordance with CFM56-3/-3B/-3C SB No. 72-530, Revision 3, dated 
November 17, 1995, within the next 75 hours TIS after the effective 
date of this AD. Thereafter, inspect the forward sump MCD at 
intervals not to exceed 75 hours TIS SLI in accordance with CFM56-3/
-3B/-3C SB No. 72-530, Revision 3, dated November 17, 1995, until 
the bearing TIS since new is 6,000 hours or more. Remove from 
service, prior to further flight, engines which exhibit MCD metallic 
debris defined as not serviceable in accordance with CFM56-3/-3B/-3C 
SB No. 72-530, Revision 3, dated November 17, 1995.
    (d) For CFM56-2 series engines equipped with No. 3 bearings, P/N 
9732M10P10; 9732M10P17; or 9732M10P12 (S/N series other than 
FAFDxxxx or FAFExxxx), inspect the forward sump MCD in accordance 
with the instructions of CFM56-2 SB No. 72-620, Revision 4, dated 
November 17, 1995, within the next 75 hours TIS after the effective 
date of this AD. Thereafter, inspect the forward sump MCD at 
intervals not to exceed 75 hours TIS SLI in accordance with CFM56-2 
SB No. 72-620, Revision 4, dated November

[[Page 49179]]

17, 1995, until the bearing TIS since new is 6,000 hours or more. 
Remove from service, prior to further flight, engines which exhibit 
MCD metallic debris defined as not serviceable in accordance with 
CFM56-2 SB No. 72-620, Revision 4, dated November 17, 1995.
    (e) For CFM56-5 series engines equipped with No. 3 bearing, P/N 
9542M60P01, inspect the forward sump MCD in accordance with CFM56-5 
Alert Service Bulletin (ASB) No. 72-A118, Revision 1, dated August 
1, 1997, within the next 50 hours TIS after the effective date of 
this AD. Thereafter, inspect the forward sump MCD at intervals not 
to exceed 50 hours TIS SLI in accordance with CFM56-5 ASB No. 72-
A118, Revision 1, dated August 1, 1997. Remove from service, prior 
to further flight, engines which exhibit MCD metallic debris defined 
as not serviceable in accordance with CFM56-5 ASB No. 72-A118, 
Revision 1, dated August 1, 1997.
    (f) Bearing inspections accomplished in accordance with AD 89-
17-04 or AD 89-23-06 satisfy the corresponding requirements of this 
AD.
    (g) For the purpose of this AD, a shop visit is defined as 
exposure of the inlet gearbox.
    (h) 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. The 
request should be forwarded 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.

    (i) 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 September 12, 1997.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 97-24909 Filed 9-18-97; 8:45 am]
BILLING CODE 4910-13-U