[Federal Register Volume 64, Number 194 (Thursday, October 7, 1999)]
[Proposed Rules]
[Pages 54589-54591]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26210]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-38-AD]
RIN 2120-AA64


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: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the supersedure of an existing 
airworthiness directive (AD), applicable to certain CFM International 
(CFMI) CFM56 series turbofan engines, that currently requires revisions 
to the Engine Time Limits section of applicable Engine Shop Manuals 
(ESMs) to include required enhanced inspection of selected critical 
life-limited parts at each piece-part exposure. This action would add 
more CFM56 engine models to the AD's applicability and introduce 
additional inspections. This proposal is prompted by additional focused 
inspection procedures that have been developed by the manufacturer. The 
actions specified by this proposed 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: Comments must be received by December 6, 1999.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 98-ANE-38-AD, 12 New England Executive Park, 
Burlington, MA 01803-5299. Comments may also be sent via the Internet 
using the following address: ``[email protected]''. Comments sent 
via the Internet must contain the docket number in the subject line. 
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 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:

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 to the address

[[Page 54590]]

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 98-ANE-38-AD.'' 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 Regional Counsel, 
Attention: Rules Docket No. 98-ANE-38-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On April 2, 1999, the Federal Aviation Administration (FAA) issued 
airworthiness directive (AD) 99-08-16, Amendment 39-11122 (64 FR 17962, 
April 13, 1999), to require revisions to the Engine Time Limits section 
of the applicable Engine Shop Manuals (ESMs) for CFM International 
(CFMI) CFM56-2, -2A, -2B, -3, -3B, and -3C series turbofan engines to 
include required enhanced inspection of selected critical life-limited 
parts at each piece-part exposure. That AD was prompted by an FAA study 
of in-service events involving uncontained failures of critical 
rotating engine parts that indicated the need for improved inspections. 
That condition, if not corrected, could result in critical life-limited 
rotating engine part failure, which could result in an uncontained 
engine failure and damage to the airplane.

New Inspection Procedures

    Since the issuance of that AD, CFMI has developed additional 
focused inspection procedures. This proposal would add the CFM56-5, -
5B, -5C, and -7B series engines to the AD's applicability. This 
proposal would also extend the currently required fluorescent penetrant 
inspections (FPI) and bore/dovetail eddy current inspections (ECI) to 
fan disks installed on the newly affected models, and extend the 
currently required high pressure turbine (HPT) disk FPI on the newly 
affected models as well. In addition, this AD would add, for all 
affected CFM56 engine models, HPT disk bore ECI. Finally, for all 
affected CFM56 engine models, this AD would add HPT front rotating air 
seal FPI, bore ECI, and bolthole ECI or focused FPI.

Proposed Actions

    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 supersede AD 99-08-16 to add more CFM56 engine models 
to the AD's applicability and introduce additional inspections. The 
inspections would be required at each piece-part opportunity.

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 would be affected by this proposed AD, that 
it would 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 
proposed new inspections on US operators is approximately $2,131,320, 
or $870 per engine.

Regulatory Impact

    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) 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 removing Amendment 39-11122 (64 FR 
17962, April 13, 1999), and by adding a new airworthiness directive, to 
read as follows:

CFM International: 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 E-3, E-6, and KC-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:

[[Page 54591]]

Inspections

    (a) Within the next 30 days after the effective date of this AD, 
revise the Time Limits section (chapter 05-11-00) 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:

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                                                                    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/-B/-3/-3B/-3C.............  High Pressure Turbine            72-52-02  Disk FPI and Disk Bore and
                                         (HPT) Disk (All P/N).                      Bold 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           72-52-03  Disk FPI and Disk Bore and
                                         Seal (All P/N).                            Bolt Hole(s) ECI.
CFM56-5/-5B/-5C/-7B...................  HPT Front rotating Air           72-52-03  Disk FPI and Disk Bore ECI
                                         Seal (All P/N).                            and Disk Bolt Hole(s)
                                                                                    Focused FPI.
CFM56-2...............................  HPT Front Rotating Air           72-52-03  Disk FPI and Disk Bore ECI
                                         Seal (All P/N).                            and Disk Bolt Hole(s) ECI or
                                                                                    focused FPI as applicable.
----------------------------------------------------------------------------------------------------------------

    (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 section 43.16 of the Federal 
Aviation Regulations (14 CFR 43.16), these mandatory inspections 
shall be performed only in accordance with the Time Limits 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 
sections 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)) of this chapter must 
maintain records of the mandatory inspections that result from 
revising the Time Limits 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.

    Issued in Burlington, Massachusetts, on September 30, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-26210 Filed 10-6-99; 8:45 am]
BILLING CODE 4910-13-P