[Federal Register Volume 60, Number 170 (Friday, September 1, 1995)]
[Proposed Rules]
[Pages 45683-45684]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-21770]
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Proposed Rules
Federal Register
________________________________________________________________________
This section of the FEDERAL REGISTER contains notices to the public of
the proposed issuance of rules and regulations. The purpose of these
notices is to give interested persons an opportunity to participate in
the rule making prior to the adoption of the final rules.
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Federal Register / Vol. 60, No. 170 / Friday, September 1, 1995 /
Proposed Rules
[[Page 45683]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-ANE-15]
Airworthiness Directives; CFM International CFM56-2/-2A/-2B/-3/-
3B/-3C/-5 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) CFM56-2/-
2A/-2B/-3/-3B/-3C/-5 series turbofan engines. This proposal would
require part number reidentification of certain low pressure turbine
rotor (LPTR) stub shafts and conical supports, and reduction of the low
cycle fatigue (LCF) retirement lives for these reidentified parts. This
proposal is prompted by the results of a refined life analysis
performed by the manufacturer which revealed minimum calculated LCF
lives significantly lower than published LCF retirement lives. The
actions specified by the proposed AD are intended to prevent a LCF
failure of the LPTR stub shaft and conical support, which could result
in an uncontained engine failure and damage to the aircraft.
DATES: Comments must be received by October 31, 1995.
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-15, 12 New England
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at
this location between 8 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. 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.
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-15.'' 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-15, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
This proposed airworthiness directive (AD) is applicable to CFM
International (CFMI) CFM56-2/-2A/-2B/-3/-3B/-3C/-5 series turbofan
engines. Numerous first production low pressure turbine rotor (LPTR)
stub shafts and conical supports were machined from thick forgings.
Parts machined from thick forgings have lower metallurgical properties
than ones machined from near net shape forgings. A study performed by
the manufacturer using updated lifing analyses revealed that these
parts have minimum calculated low cycle fatigue (LCF) lives which are
significantly lower than published LCF retirement lives. This
condition, if not corrected, could result in a LCF failure of the LPTR
stub shaft and conical support, which could result in an uncontained
engine failure and damage to the aircraft.
The FAA has reviewed and approved the technical contents of CFMI
CFM56-2 Service Bulletin (SB) No. 72-728, Revision 2, dated December
21, 1994, CFMI CFM56-2A SB No. 72-338, dated November 25, 1993, CFMI
CFM56-2B SB No. 72-476, dated December 7, 1993, and CFMI CFM56-3/-3B/-
3C SB No. 72-695, dated November 25, 1993. These SB's describe
procedures for the part number reidentification of LPTR stub shafts and
conical supports.
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 part number reidentification of certain LPTR
stub shafts and conical supports, and reduction of the LCF retirement
lives for these reidentified parts. The actions would be required to be
accomplished in accordance with the SB's described previously.
The FAA estimates that 41 engines installed on aircraft of U.S.
registry would be affected by this proposed AD, that it would take
approximately 0.25 work hours per engine to accomplish the proposed
actions, and that the average labor rate is $60 per work hour. Assuming
that the parts cost is proportional to the reduction of the LCF
retirement lives, the required parts would cost approximately $6,687
per engine. Based on these figures, the total cost impact of the
proposed AD on U.S. operators is estimated to be $274,782.
The regulations proposed herein would not have substantial direct
effects
[[Page 45684]]
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), 40101, 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-15.
Applicability: CFM International (CFMI) CFM56-2/-2A/-2B/-3/-3B/-
3C/-5 series turbofan engines installed on, but not limited to
Airbus A320 series, McDonnell Douglas DC-8 series, and Boeing 737,
E-3, E-6, and KC-135 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 (j) 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 low cycle fatigue (LCF) failure of the low pressure
turbine rotor (LPTR) stub shaft and conical support, which could
result in an uncontained engine failure and damage to the aircraft,
accomplish the following:
(a) Reidentify CFM56-2A LPTR stub shafts, Part Numbers (P/N)
301-330-623-0 and 301-330-624-0, with Serial Numbers (S/N) listed in
Table 2 of CFMI CFM56-2A Service Bulletin (SB) No. 72-338, dated
November 25, 1993, in accordance with the Accomplishment
Instructions of CFMI CFM56-2A SB No. 72-338, dated November 25,
1993, at the next piece-part exposure after the effective date of
this AD, but not to exceed 6,400 cycles since new (CSN).
(b) Reidentify CFM56-2B LPTR stub shafts, P/N 301-330-618-0,
301-330-619-0, 301-330-623-0, and 301-330-624-0, with S/N listed in
Table 2 of CFMI CFM56-2B SB No. 72-476, dated December 7, 1993, in
accordance with the Accomplishment Instructions of CFMI CFM56-2B SB
No. 72-476, dated December 7, 1993, at the next piece-part exposure
after the effective date of this AD, but not to exceed 8,300 CSN.
(c) Reidentify CFM56-2 LPTR conical supports, P/N 305-056-106-0,
305-056-109-0, 305-056-110-0, and 305-056-111-0, with S/N listed in
Table 1 of CFMI CFM56-2 SB No. 72-728, Revision 2, dated December
21, 1994, in accordance with the Accomplishment Instructions of CFMI
CFM56-2 SB No. 72-728, Revision 2, dated December 21, 1994, at the
next piece-part exposure after the effective date of this AD, but
not to exceed 18,000 CSN.
(d) Reidentify CFM56-2A LPTR conical supports, P/N 305- 056-110-
0 and 305-056-111-0, with S/N listed in Table 1 of CFMI CFM56-2A SB
No. 72-338, dated November 25, 1993, in accordance with the
Accomplishment Instructions of CFMI CFM56-2A SB No. 72-338, dated
November 25, 1993, at the next piece-part exposure after the
effective date of this AD, but not to exceed 5,700 CSN.
(e) Reidentify CFM56-2B LPTR conical supports, P/N 305-056-106-
0, 305-056-109-0, 305-056-110-0, and 305-056-111-0, with S/N listed
in Table 1 of CFMI CFM56-2B SB No. 72-476, dated December 7, 1993,
in accordance with the Accomplishment Instructions of CFMI CFM56-2B
SB No. 72-476, dated December 7, 1993, at the next piece-part
exposure after the effective date of this AD, but not to exceed
8,700 CSN.
(f) Reidentify CFM56-3B/-3C LPTR stub shafts, P/N 301-330-618-0,
301-330-619-0, 301-330-623-0, and 301-330-624-0, with S/N listed in
Table 2 of CFMI CFM56-3/-3B/-3C SB No. 72-695, dated November 25,
1993, in accordance with the Accomplishment Instructions of CFMI
CFM56-3/-3B/-3C SB No. 72-695, dated November 25, 1993, as follows:
(1) For CFM56-3B series engines, at the next piece-part exposure
after the effective date of this AD, but not to exceed 11,400 CSN.
(2) For CFM56-3C series engines, at the next piece-part exposure
after the effective date of this AD, but not to exceed 7,900 CSN.
(g) Reidentify CFM56-3/-3B/-3C LPTR conical supports, P/N 305-
056-106-0, 305-056-109-0, 305-056-110-0, and 305-056-111-0, with S/N
listed in Table 1 of CFMI CFM56-3/-3B/-3C SB No. 72-695, dated
November 25, 1993, in accordance with the Accomplishment
Instructions of CFMI CFM56-3/-3B/-3C SB No. 72-695, dated November
25, 1993, as follows:
(1) For CFM56-3 series engines, at the next piece-part exposure
after the effective date of this AD, but not to exceed 12,100 CSN.
(2) For CFM56-3B series engines, at the next piece-part exposure
after the effective date of this AD, but not to exceed 9,300 CSN.
(3) For CFM56-3C series engines, at the next piece-part exposure
after the effective date of this AD, but not to exceed 5,700 CSN.
(h) Remove from service CFM56-5 LPTR conical support, P/N 336-
000-305-0, prior to accumulating 11,300 CSN.
(i) This action establishes new LCF retirement lives for parts
reidentified in accordance with paragraphs (a) through (g) of this
AD, and the new LCF retirement life noted in paragraph (h) of this
AD, which are published in Chapter 05 of the applicable engine shop
manual (CFM56-2 CFMI-TP.SM.4, CFM56-2A/-2B CFMI-TP.SM.6, CFM56-3
CFMI-TP.SM.5, and CFM56-5 CFMI-TP.SM.7).
(j) 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.
(k) 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 August 23, 1995.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 95-21770 Filed 8-31-95; 8:45 am]
BILLING CODE 4910-13-U
