[Federal Register Volume 61, Number 108 (Tuesday, June 4, 1996)]
[Proposed Rules]
[Pages 28112-28114]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-13890]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-ANE-65]
RIN 2120-AA64
Airworthiness Directives; CFM International CFM56-5/-5B/-5C
Series 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 CFM International (CFMI) CFM56-5/-
5B/-5C series turbofan engines. This proposal would require initial and
repetitive borescope inspections of the stage 1 disk bore of certain
high pressure compressor rotor (HPCR) stage 1-2 spools for rubs and
scratches, and replacement, if found rubbed or scratched, with a
serviceable part. This proposal would also require removal and
replacement of certain stationary number 3 bearing aft air/oil seals as
terminating action to the inspection program. This proposal is prompted
by a report of an engine found with a rub on the forward corner of the
HPCR stage 1 disk bore due to contact with the stationary number 3
bearing aft air/oil seal. The actions specified by the proposed AD are
intended to prevent a failure of the stage 1 disk of the HPCR stage 1-2
spool, which could result in an uncontained engine failure and damage
to the aircraft.
DATES: Comments must be received by August 5, 1996.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 95- ANE-65, 12 New England
Executive Park, Burlington, MA 01803- 5299. Comments may also be
submitted to the Rules Docket by using the following Internet address:
``[email protected]''. 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, One
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: Robert J. Ganley, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7138, fax (617) 238-7199.
[[Page 28113]]
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 95- ANE-65.'' 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. 95-ANE- 65, 12 New England Executive Park,
Burlington, MA 01803- 5299.
Discussion
This proposed airworthiness directive (AD) is applicable to CFM
International (CFMI) CFM56-5/-5B/-5C series turbofan engines. The
Federal Aviation Administration (FAA) has received a report of an
engine found with a rub on the forward corner of the high pressure
compressor rotor (HPCR) stage 1 disk bore due to contact with the
stationary number 3 bearing aft air/oil seal. The manufacturer has
discovered a potential lack of clearance condition between the HPCR
stage 1 disk bore and certain stationary number 3 bearing aft air/oil
seals. This potential lack of clearance may result in contact between
the two parts during engine operation. The manufacturer has determined
that this lack of clearance condition is limited to engines that have a
certain stationary number 3 bearing aft air/oil seal installed. This
condition, if not corrected, could result in a failure of the stage 1
disk of the HPCR stage 1-2 spool, which could result in an uncontained
engine failure and damage to the aircraft.
The FAA has reviewed and approved the technical contents of CFM56-5
Service Bulletin (SB) No. 72-440, CFM56- 5B SB No. 72-064, and CFM56-5C
SB No. 72-229, all Revision 2, dated June 23, 1995, that describes
procedures for borescope inspections of the stage 1 disk bore of
certain HPCR stage 1-2 spools for rubs and scratches.
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 initial and repetitive borescope inspections
of the stage 1 disk bore of certain HPCR stage 1-2 spools for rubs and
scratches, and replacement, if found rubbed or scratched, with a
serviceable part. This proposal would also require removal and
replacement of certain stationary number 3 bearing aft air/oil seals as
terminating action to the inspection program. The actions would be
required to be accomplished in accordance with the SB's described
previously.
There are approximately 131 engines of the affected design in the
worldwide fleet. The manufacturer has advised the FAA that there are no
engines installed on U.S. registered aircraft that would be affected by
this AD. Therefore, there is no associated cost impact on U.S.
operators as a result of this AD. However, should an affected engine be
imported on an aircraft and placed on the U.S. registry in the future,
it would take approximately 402 work hours to accomplish the required
actions, and that the average labor rate is $60 per work hour. Required
parts would cost approximately $87,700 per engine. Based on these
figures, the cost impact of the proposed AD is estimated to be $111,820
per engine.
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 USC 106(g), 40113, 44701.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
CFM International: Docket No. 95-ANE-65.
Applicability: CFM International (CFMI) CFM56-5/-5B/- 5C series
turbofan engines, installed on but not limited to Airbus A320, A321,
and A340 series aircraft.
Note: 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 use the
authority provided in paragraph (h) to request approval from the
Federal Aviation Administration (FAA). This approval may address
either no action, if the current configuration eliminates the unsafe
condition, or different actions necessary to address the unsafe
condition described in this AD. Such a request should include an
assessment of the effect of the changed configuration on the unsafe
condition addressed by this AD. In no case does the presence of any
modification, alteration, or repair remove any engine from the
applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent a failure of the stage 1 disk of the high pressure
compressor rotor (HPCR) stage 1-2 spool, which could result in an
uncontained engine failure and damage to the aircraft, accomplish
the following:
[[Page 28114]]
(a) For CFM56-5/-5B/-5C engines that have a stationary number 3
bearing aft air/oil seal, Part Number (P/N) 1364M71G02, installed,
inspect the stage 1 disk of the HPCR stage 1-2 spool in accordance
with the Accomplishment Instructions of CFM56-5 Service Bulletin
(SB) No. 72-440, CFM56-5B SB No. 72-064, or CFM56-5C SB No. 72-229,
all Revision 2, dated June 23, 1995, as applicable, as follows:
(1) If the disk has been previously inspected prior to the
effective date of this AD, inspect prior to accumulating 2,200
cycles since new (CSN).
(2) If the disk has been previously inspected prior to the
effective date of this AD, and the disk was found not to be rubbed
or scratched, reinspect prior to accumulating 2,200 cycles since
last inspection (CSLI).
(b) Thereafter, for disks that have been inspected in accordance
with paragraph (a)(1) or (a)(2) of this AD, inspect in accordance
with the Accomplishment Instructions of CFM56-5 SB No. 72-440,
CFM56-5B SB No. 72-064, or CFM56-5C SB No. 72-229, all Revision 2,
dated June 23, 1995, as applicable, at intervals not to exceed 2,200
CSLI.
(c) Remove from service HPCR stage 1-2 spools with rubbed or
scratched stage 1 disks and replace with a serviceable part, as
follows:
(1) For spools with less than 2,200 CSN on the effective date of
this AD, at the next engine shop visit after the effective date of
this AD, or prior to accumulating 2,200 CSN, whichever occurs first.
(2) For spools with 2,200 CSN or more on the effective date of
this AD, at the next engine shop visit after the effective date of
this AD, or prior to accumulating 2,200 CSLI, whichever occurs
first.
(d) Remove from service stationary number 3 aft air/oil seals,
P/N 1364M71G02, at the next engine shop visit after the effective
date of this AD, and replace with a serviceable part. Compliance
with this paragraph constitutes terminating action to the inspection
requirements of paragraphs (a)(1), (a)(2), and (b) of this AD.
(e) For the purpose of this AD, a serviceable HPCR stage 1-2
spool is defined as a spool without a rub or scratch indication on
the stage 1 disk, a P/N 1834M55G01 spool, or a spool that has
accomplished the stage 1 disk rework in accordance with any revision
level of CFM56-5 SB No. 72-442, CFM56-5B SB No. 72-066, or CFM56-5C
SB No. 72-230, as applicable.
(f) For the purpose of this AD, a serviceable stationary number
3 bearing aft air/oil seal is defined as any seal other than a P/N
1364M71G02 seal.
(g) For the purpose of this AD, an engine shop visit is defined
as the induction of an engine into the shop for any reason.
(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: 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 May 22, 1996.
Robert E. Guyotte,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 96-13890 Filed 6-3-96; 8:45 am]
BILLING CODE 4910-13-U