[Federal Register Volume 61, Number 59 (Tuesday, March 26, 1996)]
[Proposed Rules]
[Pages 13110-13111]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-7243]
========================================================================
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.
========================================================================
Federal Register / Vol. 61, No. 59 / Tuesday, March 26, 1996 /
Proposed Rules
[[Page 13110]]
DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-ANE-64]
Airworthiness Directives; CFM International CFM56-5C Series
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Notice of proposed rulemaking (NPRM).
-----------------------------------------------------------------------
SUMMARY: This document proposes the adoption of a new airworthiness
directive (AD) that is applicable to CFM International (CFMI) CFM56-
5C2/G, -5C3/G, and -5C4 series turbofan engines. This proposal would
require a reduction of the low cycle fatigue (LCF) retirement lives for
certain high pressure turbine rotor (HPTR) front shafts, HPTR front air
seals, HPTR disks, booster spools, and low pressure turbine rotor
(LPTR) stage 3 disks. This proposal is prompted by the results of a
refined life analysis performed by the manufacturer which revealed
minimum calculated LCF lives lower than published LCF retirement lives.
The actions specified by the proposed AD are intended to prevent an LCF
failure of the HPTR front shaft, HPTR front air seal, HPTR disk,
booster spool, and LPTR stage 3 disk, which could result in an
uncontained engine failure and damage to the aircraft.
DATES: Comments must be received by May 28, 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-64, 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.
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-64.'' 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-64, 12 New England Executive Park,
Burlington, MA 01803-5299.
Discussion
This proposed airworthiness directive (AD) is applicable to CFM
International (CFMI) CFM56-5C2/G, -5C3/G, and -5C4 series turbofan
engines. The manufacturer performed a study using updated lifing
analyses that revealed certain high pressure turbine rotor (HPTR) front
shafts, HPTR front air seals, HPTR disks, booster spools, and low
pressure turbine rotor (LPTR) stage 3 disks have minimum calculated low
cycle fatigue (LCF) lives which are lower than published LCF retirement
lives. These reduced LCF lives are due to changes in component
operating environments, which are associated with the incorporation of
the takeoff mach bump in the analysis. This condition, if not
corrected, could result in an LCF failure of the HPTR front shaft, HPTR
front air seal, HPTR disk, booster spool, and LPTR stage 3 disk, which
could result in an uncontained engine failure and damage to the
aircraft..
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 a reduction of the LCF retirement lives for
certain HPTR front shafts, HPTR front air seals, HPTR disks, booster
spools, and LPTR stage 3 disks.
There are approximately 10 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 not take any additional work hours per engine to accomplish
the proposed actions. Assuming that the parts cost is proportional to
the reduction of the LCF retirement lives, the required parts would
cost approximately $25,736 per engine. Based on these figures, the
total cost impact of the AD is estimated to be $25,736 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)
[[Page 13111]]
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 U.S.C. 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-64.
Applicability: CFM International (CFMI) CFM56-5C2/G, -5C3/G, and
-5C4 series turbofan engines, installed on but not limited to Airbus
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 low cycle fatigue (LCF) failure of the high
pressure turbine rotor (HPTR) front shaft, HPTR front air seal, HPTR
disk, booster spool, and low pressure turbine rotor (LPTR) stage 3
disk, which could result in an uncontained engine failure and damage
to the aircraft, accomplish the following:
(a) Remove from service HPTR front shafts, Part Numbers (P/N's)
1498M40P03, 1498M40P05, and 1498M40P06, prior to accumulating 8,400
cycles since new (CSN), and replace with a serviceable part.
(b) Remove from service HPTR front air seals, P/N's 1523M34P02
and 1523M34P03, prior to accumulating 4,000 CSN, and replace with a
serviceable part.
(c) Remove from service HPTR disks, P/N 1498M43P04, prior to
accumulating 6,200 CSN, and replace with a serviceable part.
(d) Remove from service booster spools, P/N 337-005-210-0, prior
to accumulating 13,800 CSN, and replace with a serviceable part.
(e) Remove from service LPTR stage 3 disks, P/N's 337-001-602-0
and 337-001-605-0, prior to accumulating 8,630 CSN, and replace with
a serviceable part.
(f) This action establishes the new LCF retirement lives stated
in paragraphs (a) through (e) of this AD, which are published in
Chapter 05 of the CFM56 Engine Shop Manual, CFMI-TP.SM.8.
(g) For the purpose of this AD, a ``serviceable part'' is one
that has not exceeded its respective new life limit as set out in
this AD.
(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 March 12, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 96-7243 Filed 3-25-96; 8:45 am]
BILLING CODE 4910-13-P