Airworthiness Directives; CFM International CFM56-5 Series Turbofan Engines

[Federal Register Volume 64, Number 54 (Monday, March 22, 1999)]
[Rules and Regulations]
[Pages 13667-13669]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-6555]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-56-AD; Amendment 39-11079; AD 99-06-16]
RIN 2120-AA64


Airworthiness Directives; CFM International CFM56-5 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), 
applicable to CFM International CFM56-5 series turbofan engines, that 
reduces the low cycle fatigue (LCF) retirement lives for certain high 
pressure turbine rotor (HPTR) front air seals, and provides a drawdown 
schedule for those affected parts with reduced LCF retirement lives. 
This amendment is prompted by results of a refined life analysis 
performed by the manufacturer that revealed minimum calculated LCF 
lives significantly lower than the published LCF retirement lives. The 
actions specified by this AD are intended to prevent a LCF failure of 
the HPTR front air seal, which could result in an uncontained engine 
failure and damage to the aircraft.

DATES: Effective April 21, 1999.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director

[[Page 13668]]

of the Federal Register as of April 21, 1999.

ADDRESSES: The service information referenced in this AD 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 Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA; or at the 
Office of the Federal Register, 800 North Capitol Street, NW, suite 
700, Washington, DC.

FOR FURTHER INFORMATION CONTACT: Robert Ganley, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7138; fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an airworthiness 
directive (AD) that is applicable to CFM International CFM56-5 series 
turbofan engines was published in the Federal Register on September 18, 
1998 (63 FR 49879). That action proposed to require reducing the low 
cycle fatigue (LCF) retirement lives for certain high pressure turbine 
rotor (HPTR) front air seals, and provide a drawdown schedule for those 
affected parts with reduced LCF retirement lives in accordance with CFM 
International CFM56-5 Service Bulletin No. 72-541, dated July 27, 1998.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    One commenter states that the total cost impact of the proposed AD 
on the industry will be greater than that presented in the proposed 
AD's economic analysis. This commenter states that numerous engines 
currently in their fleet, and engines to be delivered in 1999, will 
require premature removal due to the life reduction of the HPTR front 
air seal. The commenter further states that engines prematurely removed 
will still have serviceable life remaining at the time of removal. The 
FAA does not concur. The proposed AD's economic analysis already 
accounts for the cost impact associated with a premature removal of the 
HPTR front air seal due to the life reduction. Therefore, the FAA has 
determined that there is no need to revise the cost impact section of 
the AD.
    One commenter supports the AD as proposed.
    After careful review of the available data, including the comments 
noted above, the FAA has determined that air safety and the public 
interest require the adoption of the rule as proposed.
    There are approximately 863 engines of the affected design in the 
worldwide fleet. The FAA estimates that 131 engines installed on 
aircraft of U.S. registry would be affected by this AD, and that it 
will not take any additional work hours per engine to accomplish the 
required actions. Assuming that the parts cost is proportional to the 
reduction of the LCF retirement lives, the required parts would cost 
approximately $14,000 per engine. Based on these figures, the total 
cost impact of the AD on U.S. operators is estimated to be $1,834,000.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this action (1) is 
not a ``significant regulatory action'' under Executive Order 12866; 
(2) is not a ``significant rule'' under DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) 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 final evaluation has been prepared for this action 
and it is contained in the Rules Docket. A copy of it may be obtained 
from the Rules Docket at the location provided under the caption 
ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Incorporation by 
reference, Safety.

Adoption of the Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration amends 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:

99-06-16  CFM International: Amendment 39-11079. Docket 98-ANE-56-
AD.

    Applicability: CFM International CFM56-5 series turbofan engines 
installed on, but not limited to, Airbus A319 and A320 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 (g) 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 low cycle fatigue failure of the high pressure 
turbine rotor (HPTR) front air seal, which could result in an 
uncontained engine failure and damage to the aircraft, accomplish 
the following:
    (a) Remove from service CFM International CFM56-5-A1 and -5-A1/F 
HPTR front air seals, Part Number (P/N) 1319M11P06, 1319M11P07, 
1319M11P08, and 1319M11P09, and CFM56-5-A1 HPTR front air seals, P/N 
1319M11P05, and replace with a serviceable part, in accordance with 
CFM56-5 Service Bulletin (SB) No. 72-541, dated July 27, 1998, as 
follows:
    (1) For seals that have accumulated less than 4,000 cycles since 
new (CSN) on the effective date of this AD, remove the seal from 
service prior to accumulating 11,000 CSN.
    (2) For seals that have accumulated 4,000 CSN or more, but less 
than 11,000 CSN on the effective date of this AD, accomplish the 
following:
    (i) For engines that have an engine shop visit (ESV) prior to 
the seal accumulating 11,000 CSN, remove the seal from service prior 
to the seal accumulating 11,000 CSN.
    (ii) For engines that do not have an ESV prior to the seal 
accumulating 11,000 CSN, remove the seal from service prior to the 
seal accumulating 7,000 cycles in service (CIS) after the effective 
date of this AD, or prior to the seal accumulating 15,300 CSN, 
whichever occurs first.
    (3) For seals that have accumulated 11,000 CSN or more on the 
effective date of this AD, remove the seal from service at the next 
ESV, or prior to the seal accumulating 15,300 CSN, whichever occurs 
first.
    (b) Remove from service CFM International CFM56-5A3 HPTR front 
air seals, P/N 1319M11P06, 1319M11P07, 1319M11P08, and 1319M11P09, 
and replace with a serviceable part, in accordance with CFM56-

[[Page 13669]]

5 SB No. 72-541, dated July 27, 1998, as follows:
    (1) For seals that have accumulated less than 3,000 CSN on the 
effective date of this AD, remove the seal from service prior to 
accumulating 7,700 CSN.
    (2) For seals that have accumulated 3,000 CSN or more, but less 
than 7,700 CSN on the effective date of this AD, accomplish the 
following:
    (i) For engines that have an ESV prior to the seal accumulating 
7,700 CSN, remove the seal from service prior to the seal 
accumulating 7,700 CSN.
    (ii) For engines that do not have an ESV prior to the seal 
accumulating 7,700 CSN after the effective date of the AD, remove 
the seal from service prior to the seal accumulating 4,700 CIS after 
the effective date of this AD, or prior to the seal accumulating 
13,000 CSN, whichever occurs first.
    (3) For seals that have accumulated 7,700 CSN or more on the 
effective date of this AD, remove the seal from service at the next 
ESV, or prior to the seal accumulating 13,000 CSN, whichever occurs 
first.
    (c) For CFM56-5A4, -5A4/F, -5A5, and -5A5/F HPTR front air 
seals, P/N 1319M11P05, 1319M11P06, 1319M11P07, 1319M11P08, and 
1319M11P09, that have previously operated in CFM56-5-A1, -5-A1/F, or 
-5A3 engine models, recalculate the HPTR front air seal total cycles 
remaining using 11,000 cycles for the CFM56-5-A1 and CFM56-5-A1/F 
engine models, and 7,700 cycles for the CFM56-5A3 engine model, in 
accordance with CFM56-5 SB No. 72-541, dated July 27, 1998, within 
750 CIS after the effective date of this AD.

    Note 2: The current HPTR front air seal retirement life for the 
CFM56-5A4, -5A4/F, -5A5, and -5A5/F engine models is 9,100 cycles, 
and is not affected by this AD.
    Note 3: For additional information on recalculating the HPTR 
front air seal total cycles remaining see Chapter 05, Section 05-11-
00, of the CFM56-5 series Engine Shop Manual, CFMI-TP.SM.7.

    (d) This AD establishes new LCF retirement lives of 11,000 
cycles for CFM56-5-A1 and -5-A1/F HPTR front air seals, and 7,700 
cycles for CFM56-5A3 HPTR front air seals, which is published in 
Chapter 05, Section 05-11-03, of the CFM56-5 series Engine Shop 
Manual, CFMI-TP.SM.7. The following conditions also apply:
    (1) Except as provided in paragraph (g) of this AD, no 
alternative retirement lives may be approved for the CFM56-5-A1, -5-
A1/F, and -5A3 HPTR front air seals.
    (2) After the effective date of this AD, no CFM56-5-A1 and -5-
A1/F HPTR front air seals may be installed or reinstalled on an 
engine if the seals have accumulated more than 11,000 CSN.
    (3) After the effective date of this AD, no CFM56-5A3 HPTR front 
air seals may be installed or reinstalled on an engine if the seals 
have accumulated more than 7,700 CSN.
    (e) For the purpose of this AD, an ``engine shop visit'' is 
defined as the induction of an engine into the shop for maintenance 
involving the separation of any major mating engine flanges, or the 
removal of a disk or spool, except that the separation of engine 
flanges solely for the purposes of transportation without subsequent 
engine maintenance does not constitute an engine shop visit.
    (f) For the purpose of this AD, a ``serviceable part'' is 
defined as one that has not exceeded its respective new retirement 
life as set out in this AD.
    (g) 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. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, Engine Certification Office.

    Note 4: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the Engine Certification Office.

    (h) 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.
    (i) The actions required by this AD shall be done in accordance 
with the following CFM International SB:

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        Document No.                  Pages                 Date
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CFM56-5 SB No. 72-541.......  1-8.................  July 27, 1998.
  Total Pages: 8.
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    This incorporation by reference was approved by the Director of 
the Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR 
part 51. Copies may be obtained from CFM International, Technical 
Publications Department, 1 Neumann Way, Cincinnati, OH 45215; 
telephone (513) 552-2981, fax (513) 552-2816. Copies may be 
inspected at the FAA, New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA; or at the 
Office of the Federal Register, 800 North Capitol Street NW, suite 
700, Washington, DC.
    (j) This amendment becomes effective on April 21, 1999.

    Issued in Burlington, Massachusetts, on March 11, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-6555 Filed 3-19-99; 8:45 am]
BILLING CODE 4910-13-P

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