[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).

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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]

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