AD 2000-12-01

[Federal Register Volume 65, Number 114 (Tuesday, June 13, 2000)]
[Rules and Regulations]
[Pages 37031-37034]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-14788]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-38-AD; Amendment 39-11779; AD 2000-12-01]
RIN 2120-AA64


Airworthiness Directives; Airworthiness Directives; CFM 
International (CFMI) CFM56-2, -2A, -2B, -3, -3B, -3C, -5, -5B, -5C, and 
-7B Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment supersedes an existing airworthiness directive 
(AD), applicable to certain CFM International (CFMI) CFM56 series 
turbofan engines,

[[Page 37032]]

that requires revisions to the Airworthiness Limitations Section of 
applicable Engine Shop Manuals (ESMs). These revisions incorporate 
required enhanced inspection of selected critical life-limited parts at 
each piece-part exposure. This amendment requires the addition of CFM56 
engine models to the applicability section of the AD, and the 
introduction of additional inspections. This amendment is prompted by 
additional focused inspection procedures that have been developed by 
the manufacturer. The actions specified by this AD are intended to 
prevent critical life-limited rotating engine part failure, which could 
result in an uncontained engine failure and damage to the airplane.

DATES: Effective date December 11, 2000.

ADDRESSES: The Rules Docket may be examined at the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, 12 New England Executive Park, Burlington, MA 01803-5299.

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) by superseding AD 99-08-16, 
Amendment 39-11122 (64 FR 17962, April 13, 1999), applicable to CFM 
International (CFMI) CFM56-2, -2A, -2B, -3, -3B, and -3C series 
turbofan engines, was published in the Federal Register on October 7, 
1999 (64 FR 54589). That action proposed to require the addition of 
CFM56 engine models to the applicability section of the AD and the 
introduction of additional inspections.

Comments Received

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Effective Date

    Several commenters request that the effective date of the AD be set 
to allow for sufficient time for publication of the procedures, 
procurement of the equipment, and training.
    The FAA agrees. The effective date for the final rule will be set 
at 180 days after publication in the Federal Register.

Extend Notice of Proposed Rulemaking (NPRM) Comment Period

    Two commenters request that the NPRM comment period be extended 
until after the proposed inspections are published, to allow time for 
the operators to review the specific inspections that will be required.
    The FAA does not agree. The nature and scope of the added 
inspections are not significantly different from existing inspections. 
Additionally, the effective date of this AD has been set to 180 days 
after publication of the AD, to allow time for the specific procedures 
to be published. Operators may submit comments to the docket file on 
the specific procedures, once they are published; the FAA will then 
consider an extension of the effective date or additional rulemaking, 
as necessary. The FAA does not believe that this final rule should be 
delayed pending the publication of the inspection procedures.

NPRM Preamble

    One commenter notes that the preamble for the NPRM supersedure does 
not exactly track the preamble for the NPRM for the current AD. 
Specifically, the commenter notes that the supersedure preamble does 
not contain the explanation as to when the enhanced disk inspections 
are required; the commenter is concerned that the inspection program is 
being changed from the current AD. The commenter requests that the FAA 
change the preamble for the NPRM supersedure to reflect the content of 
the NPRM published for the current AD.
    The FAA does not agree. The inspection program established by the 
current AD remains unchanged. This proposal does not change how air 
carriers must manage the inspection program. As stated in the NPRM for 
the current AD, future ADs may be issued to introduce additional 
intervention strategies in order to further reduce uncontained engine 
failures. This could include ADs that add new parts to the list of 
parts inspected. The inspection program established by the current AD, 
however, will remain in place unless specifically altered in a future 
proposal.

Unsafe Condition

    One commenter objects to the language in the preamble of the NPRM 
supersedure for the second phase of enhanced inspections, which 
includes a finding of an ``unsafe condition.'' The commenter requests 
that the term ``unsafe condition'' be deleted and replaced with the 
justification language from the original NPRM.
    The FAA does not agree. This commenter does not disagree with the 
proposed rule itself, but with the term ``unsafe condition'' contained 
in the preamble to the NPRM. It is not the intent of the FAA to 
completely change the enhanced disk inspection program established by 
the current AD, which evolved as a cooperative effort between the FAA 
and industry. This intervention strategy was designed to reduce the 
number of uncontained engine failures by mandating enhanced 
nondestructive inspections of critical components that could most 
likely result in a hazard to the airplane in the event of a disk 
failure. Since the engine maintenance manuals did not mandate these 
enhanced inspections, the current AD was necessary to establish the 
inspection program as an airworthiness limitation. Regardless of the 
fact that it was not stated explicitly in the original NPRM, the FAA 
determined that an ``unsafe condition'' existed because the engine 
maintenance manuals did not contain enhanced inspections as an 
airworthiness limitation. The intent was not to imply any defect in the 
actual engine hardware, but simply to state that the maintenance 
manuals, which form part of the approved engine design, must be revised 
to mandate the enhanced inspections. The supersedure repeats that 
finding with respect to the additional parts being added to the 
enhanced inspection program. Because a finding of an ``unsafe 
condition'' is a requirement for the issuance of an AD, future NPRMs to 
add parts to the program will also include that finding.

Cycles in Service

    One commenter requests that the FAA change the cycles in service in 
paragraph (2)(ii) of the mandatory inspections language contained in 
paragraph (a) from 100 cycles to 300 cycles. The commenter believes 
that a 300 cycle interval is more representative of its A-check 
interval.
    The FAA does not agree. The FAA is aware that although cracks can 
be missed during part inspections, the probability of detecting a crack 
increases each time a part is processed through an inspection line. 
Commonly used on-condition maintenance plans make it likely that a 
given part could be returned to service for thousands of cycles without 
the need for additional focused inspection. The FAA established the 100 
cycle threshold in recognition of the two opposing aspects of part 
removal and inspection, i.e., a need for a brief exemption period 
following the performance of mandatory inspections and the benefits of 
increased frequency of inspection. The

[[Page 37033]]

time between A-check intervals or crack growth time was not a factor in 
the determination of the threshold for exempting parts from focused 
inspection. The threshold is based strictly on keeping the frequency of 
mandatory inspection as high as practical, to increase the probability 
of crack detection while providing a brief window of exemption from 
mandatory inspection if certain conditions are met. The FAA will not 
revise paragraph (2)(ii) of the mandatory inspections language in 
paragraph (a) of the final rule.

Estimated Annual Cost

    One commenter suggests that the total estimated annual cost of $870 
per engine for the proposed inspections is not accurate. The commenter 
suggests that a total annual cost of $2,271 per engine is more 
accurate, based on its estimation of piece-part exposure rate.
    The FAA does not agree. The total estimated annual cost per engine 
noted in the economic analysis of the NPRM is representative of the 
piece-part exposure rate of all affected U.S. operators, not one 
specific operator. The FAA will not revise the economic analysis of the 
final rule.

Addition to Applicability Section

    One commenter suggests adding the Airbus Industrie A318 and Boeing 
C-135 (military) series airplanes to the applicability section of the 
final rule.
    The FAA partially agrees. Currently, no A318 aircraft are powered 
by CFM56 engines; this series will not be added to the final rule. The 
applicability section of the final rule will be revised to add the 
Boeing C-135 (military) series airplanes; the Boeing KE-3 (military) 
and RC-135 (military) series airplanes will also be added, to be 
complete.

Clarification of Paragraph (e)

    One commenter requests that the FAA delete the phrase ``of this 
chapter'' from the first sentence of paragraph (e) of the compliance 
section, to improve the clarity of this paragraph.
    The FAA agrees. The words ``of this chapter'' have been deleted 
from paragraph (e).

``Time Limits Section''

    One commenter recommends replacing references to the ``Time Limits 
Section'' with references to the more general ``Airworthiness 
Limitations Section,'' since Chapter 5 now contains two subsets, 05-11-
00 for life limits and 05-21-00 for mandatory inspections. The 
commenter also recommends replacing the references to ``chapter 05-11-
00'' with ``chapter 05-00-00.''
    Another commenter recommends replacing references to the ``Time 
Limits Section'' with ``Life Limits Section,'' to eliminate confusion. 
The commenter also recommends replacing references to ``chapter 05-11-
00'' with ``chapter 05-21-00,'' because Chapter 5 now contains a new 
section, 05-21-00, for the mandatory inspections.
    The FAA partially agrees. The references to the ``Time Limits 
Section'' have been changed in the final rule to the more general 
``Airworthiness Limitations Section.'' The references to ``chapter 05-
11-00'' have been changed in the final rule to ``chapter 05-00-00.''

Revisions to the Table

    Three commenters suggest revising the table in paragraph (1) of the 
mandatory inspections language contained in paragraph (a) of the 
proposed AD to correct minor typographical errors to eliminate 
confusion. The suggested revisions are as follows:
    <bullet> Replace ``Bold'' with ``Bolt'' in the Inspection column 
for the CFM56-2/-2A/-2B/-3/-3B/-3C HPT Disk;
    <bullet> Replace ``Bold'' with ``Rim Bolt'' in the Inspection 
column for the CFM56-2/-2A/-2B/-3/-3B/-3C HPT Disk; and
    <bullet> Replace ``Disk'' with ``Seal'' in the Inspection column 
for the HPT Front Rotating Air Seal.
    The FAA agrees. The FAA has corrected the typographical errors and 
has also made the following corrections:
    <bullet> Replaced ``-B'' with ``-2B'' in the Engine models column 
for the HPT Disk; and
    <bullet> Capitalized the word ``rotating'' in the Part name column 
for the CFM56-5/-5B/-5C/-7B.

Adoption of the Rule as Proposed

    Three commenters support the adoption of the rule as proposed.

Conclusion

    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 with the changes described 
previously. The FAA has determined that these changes will neither 
increase the economic burden on any operator nor increase the scope of 
the AD.

Economic Analysis

    There are approximately 6,953 engines of the affected design in the 
worldwide fleet. The FAA estimates that 2,453 engines installed on 
airplanes of U.S. registry will be affected by this AD, that it will 
take approximately 30 work hours per engine for the fan disk 
inspection, 13 work hours for the HPT disk inspection, and 13 work 
hours for the HPT front rotating air seal inspection. The average labor 
rate is $60 per work hour. Using average shop visitation rates, 554 fan 
disks, 891 HPT disks, and 563 HPT front rotating air seals are expected 
to be affected per year. The total estimated annual cost of the AD on 
U.S. operators is approximately $2,131,320, or $870 per engine.

Regulatory Impact

    This rule does not have federalism implications, as defined in 
Executive Order 13132, because it does not have a substantial direct 
effect 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this rule.
    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, 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 removing Amendment 39-11122 (64 FR 
17962, April 13, 1999) and by adding a new airworthiness directive,

[[Page 37034]]

Amendment 39-11779, to read as follows:

2000-12-01  CFM International: Amendment 39-11779. Docket No. 98-
ANE-38-AD. Supersedes AD 99-08-16, Amendment 39-11122.

    Applicability: CFM International (CFMI) CFM56-2, -2A, -2B, -3, -
3B, -3C, -5, -5B, -5C, and -7B series turbofan engines, installed on 
but not limited to McDonnell Douglas DC-8 series, Boeing 737 series, 
Airbus Industrie A319, A320, A321, and A340 series, as well as 
Boeing C-135, E-3, E-6, KC-135, KE-3, and RC-135 (military) series 
airplanes.

    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 (c) 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 critical life-limited rotating engine part failure, 
which could result in an uncontained engine failure and damage to 
the airplane, accomplish the following:

Inspections

    (a) Within the next 30 days after the effective date of this AD, 
revise the Airworthiness Limitations Section (chapter 05-00-00) of 
Engine Shop Manual (ESM) CFMI-TP.SM.4 for CFM56-2 series engines, 
ESM CFMI-TP.SM.6 for CFM56-2A/-2B series engines, ESM CFMI-TP.SM.5 
for CFM56-3/-3B/-3C series engines, ESM CFMI-TP.SM.7 for CFM56-5 
series engines, ESM CFMI-TP.SM.9 for CFM56-5B series engines, ESM 
CFMI-TP.SM.8 for CFM56-5C series engines, and ESM CFMI-TP.SM.10 for 
CFM56-7B series engines, and for air carrier operations, revise the 
approved continuous airworthiness maintenance program, by adding the 
following:

``MANDATORY INSPECTIONS

    (1) Perform inspections of the following parts at each piece-
part opportunity in accordance with the Inspection/Check section 
instructions provided in the applicable manual sections listed 
below:

----------------------------------------------------------------------------------------------------------------
                                                                    Engine manual
           Engine models                      Part name                section                Inspection
----------------------------------------------------------------------------------------------------------------
All................................  Fan Disk (All Part Number             72-21-03  Disk Fluorescent Penetrant
                                      (P/N)).                                         Inspection (FPI) and Disk
                                                                                      Bore and Dovetail Eddy
                                                                                      Current Inspection (ECI).
CFM56-2/-2A/-2B/-3/-3B/-3C.........  High Pressure Turbine (HPT)           72-52-02  Disk FPI and Disk Bore and
                                      Disk (All P/N).                                 Rim Bolt Hole(s) ECI.
CFM56-5/-5B/-5C/-7B................  HPT Disk (All P/N).........           72-52-02  Disk FPI and Disk Bore ECI.
CFM56-2A/-2B/-3/-3B/-3C............  HPT Front Rotating Air Seal           72-52-03  Seal FPI and Seal Bore and
                                      (All P/N).                                      Bolt Hole(s) ECI.
CFM56-5/-5B/-5C/-7B................  HPT Front Rotating Air Seal           72-52-03  Seal FPI and Seal Bore ECI
                                      (All P/N).                                      and Seal Bolt Hole(s)
                                                                                      Focused FPI.
CFM56-2............................  HPT Front Rotating Air Seal           72-52-03  Seal FPI and Seal Bore ECI
                                      (All P/N).                                      and Seal Bolt Hole(s) ECI
                                                                                      or focused FPI as
                                                                                      applicable.
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    (2) For the purposes of these mandatory inspections, piece-part 
opportunity means:
    (i) The part is considered completely disassembled when 
accomplished in accordance with the disassembly instructions in the 
manufacturer's engine manual; and
    (ii) The part has accumulated more than 100 cycles in service 
since the last piece-part opportunity inspection, provided that the 
part was not damaged or related to the cause for its removal from 
the engine.''
    (b) Except as provided in paragraph (c) of this AD, and 
notwithstanding contrary provisions in Sec. 43.16 of the Federal 
Aviation Regulations (14 CFR 43.16), these mandatory inspections 
shall be performed only in accordance with the Airworthiness 
Limitations Section of the manufacturer's ESM.

Alternative Methods of Compliance

    (c) 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 Engine Certification Office (ECO). Operators 
shall submit their requests through an appropriate FAA Principal 
Maintenance Inspector (PMI), who may add comments and then send it 
to the ECO.

    Note 2: Information concerning the existence of approved 
alternative methods of compliance with this airworthiness directive, 
if any, may be obtained from the ECO.

Ferry Flights

    (d) Special flight permits may be issued in accordance with 
Sec. Sec. 21.197 and 21.199 of the Federal Aviation Regulations (14 
CFR 21.197 and 21.199) to operate the airplane to a location where 
the requirements of this AD can be accomplished.

Continuous Airworthiness Maintenance Program

    (e) FAA-certificated air carriers that have an approved 
continuous airworthiness maintenance program in accordance with the 
record keeping requirement of Sec. 121.369(c) of the Federal 
Aviation Regulations (14 CFR 121.369(c)) must maintain records of 
the mandatory inspections that result from revising the 
Airworthiness Limitations Section of the applicable ESM and the air 
carrier's continuous airworthiness program. Alternately, 
certificated air carriers may establish an approved system of record 
retention that provides a method for preservation and retrieval of 
the maintenance records that include the inspections resulting from 
this AD, and include the policy and procedures for implementing this 
alternate method in the air carrier's maintenance manual required by 
Sec. 121.369(c) of the Federal Aviation Regulations (14 CFR 
121.369(c)); however, the alternate system must be accepted by the 
appropriate PMI and require the maintenance records be maintained 
either indefinitely or until the work is repeated. Records of the 
piece-part inspections are not required under Sec. 121.380(a)(2)(vi) 
of the Federal Aviation Regulations (14 CFR 121.380(a)(2)(vi)). All 
other operators must maintain the records of mandatory inspections 
required by the applicable regulations governing their operations.

    Note 3: The requirements of this AD have been met when the ESM 
changes are made and air carriers have modified their continuous 
airworthiness maintenance plans to reflect the requirements in the 
applicable ESM.

Effective Date

    (f) This amendment becomes effective on December 11, 2000.

    Issued in Burlington, Massachusetts, on June 5, 2000.
Diane S. Romanosky,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-14788 Filed 6-12-00; 8:45 am]
BILLING CODE 4910-13-U