[Federal Register Volume 65, Number 79 (Monday, April 24, 2000)]
[Rules and Regulations]
[Pages 21636-21638]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10158]



[[Page 21636]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-41-AD; Amendment 39-11697; AD 2000-08-11]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-6, CF6-45, 
and CF6-50 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 General Electric Company (GE) CF6-6, CF6-45, and 
CF6-50 series turbofan engines, that requires revisions to the Time 
Limits Section of the manufacturer's Instructions for Continued 
Airworthiness (ICA) to include required enhanced inspection of selected 
critical life-limited parts at each piece-part exposure. This action 
would add additional eddy current inspections (ECI) for the high 
pressure turbine rotor (HPTR) Stage 1 and 2 disks. This action 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 October 23, 2000.

ADDRESSES: The information referenced in this AD may be examined at the 
Federal Aviation Administration (FAA), New England Region, Office of 
the Regional Counsel, 12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Karen Curtis, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7192, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding AD 99-08-18, 
Amendment 39-11124 (64 FR 17958, April 13, 1999) which is applicable to 
General Electric Company (GE) CF6-6, CF6-45, and CF6-50 series turbofan 
engines was published in the Federal Register on October 7, 1999 (64 FR 
54587). That action proposed to require disk bore eddy current 
inspections (ECI) for the high pressure turbine rotor (HPTR) Stage 1 
and 2 disks.

New Inspection Procedures

    Since the issuance of that AD, additional focused inspection 
procedures for other critical life-limited rotating engine parts have 
been developed by GE. This AD will require modification of the 
airworthiness limitations section in the manufacturers manual and an 
air carrier's approved continuous airworthiness maintenance program to 
incorporate these inspection procedures.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Objection to the Term ``Unsafe Condition'' in the Preamble of the 
NPRM

    Two commenters object 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 commenters asks that the term 
``unsafe condition'' be deleted and replaced with the justification 
language from the original NPRM. The FAA does not agree. The commenter 
does not disagree with the proposed rule itself but rather with the 
term ``unsafe condition'' that is 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 
rotating components that could most likely result in a hazard to the 
airplane in the event of a 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. There was no intent to 
imply any defect in the actual engine hardware, but simply to state 
that the maintenance manuals, that 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 required for the FAA to issue an AD, future 
NPRM's adding parts to the program will also include that finding.

Requests To Add an Explanation to the Preamble of This AD, of When 
the Inspections Are Not Required

    Several commenters request that the FAA change the preamble that 
was published in the NPRM to state when the enhanced inspections are 
not required. The commenters note that the preamble to this NPRM does 
not contain an explanation as to when the enhanced disk inspections are 
not required and express concern that the inspection program has been 
changed from the current AD. The FAA does not agree. The inspection 
program established by the current AD has not been changed. The NPRM 
adds additional parts to the list of parts that must be inspected, and 
does not change how air carriers must manage the inspection program. 
Future AD's may be issued to introduce additional intervention 
strategies in order to further reduce uncontained engine failures.These 
may include AD's to add new parts to the list of parts to be inspected. 
The inspection program established by the current AD will remain 
unchanged unless specifically changed in a future proposal.

Request to Change All References From ``Time Limits Section'' to 
``Airworthiness Limitations Section''

    One commenter, the engine manufacturer, asks that we change 
references to the ``Time Limits Section'' to read instead the 
``revision to the Airworthiness Limitations Section.'' The commenter 
feels that it is more accurate to refer to the Airworthiness Limitation 
Section since this section, Chapter 5, now contains two subsets; 05-11 
for Time Limits and 05-21 for the mandatory inspections. The FAA does 
not agree. The manufacturer's current engine manual does not include 
the heading ``Airworthiness Limitations'' for Chapter 05-00-00 for 
these engine models, and the AD directs that changes be made to the 
current manual. Should the manufacturer revise the section headings in 
the manual, any future AD's could then reference the revised section 
headings.

Request for Clarification of When FAA Approval or AMOC Is Required

    One commenter requests clarification be added to this AD on when 
equivalent substitutes for tools, equipment, or procedures used for 
performing the mandatory enhanced inspections require FAA approval or 
an approved alternate method of compliance (AMOC).

[[Page 21637]]

    The FAA does not agree that further clarification is necessary in 
the AD. When allowed for in an AD, an AMOC provides a method by which 
an operator may secure FAA approval for complying with the requirements 
of that AD in a manner or at a time other than specified by the AD. 
This AD, and other similar AD's issued as part of the so-called Disk 
Inspection Initiative of the Safer Skies Program, are intended to 
address the need to include mandatory detail inspections in the FAA 
approved portion of the engine maintenance manual. This portion of the 
engine maintenance manual is sometimes referred to as the Airworthiness 
Limitations Sections (ALS) of the Instructions for Continued 
Airworthiness. The FAA does not intend that this AD specify the exact 
method or tools with which to conduct the inspection. Rather, the AD 
requires only that the ALS be revised to include a mandatory 
opportunistic inspection. The FAA also does not intend that this AD 
change the manner in which operators seek approval to use tools or 
methods of inspections other than those provided for in the engine 
manufacturer's manual. Operators, particularly air carriers, should 
follow the procedures already in place to secure FAA review and 
approval to use such substitutes, if needed, and to document that 
approval if necessary. Therefore, the AMOC paragraph in the AD will 
remain as proposed.

Request To Extend the Comment Period

    One commenter requests 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 FAA believes that the nature and scope of 
the added inspections will not be significantly different from existing 
inspections. In addition, the effective date of this AD has been 
extended to 180 days after publication to allow time for the specific 
procedures to be published. Operators may submit comments on the 
specific procedures once they are published and the FAA will consider 
extending the effective date further or additional rulemaking, as 
necessary. The FAA does not believe, however, that this final rule need 
be delayed pending the publication of the inspection procedures.

Request To Allow a Later Effective Date

    Several commenters request that the effective date of the AD be set 
to allow sufficient time for publication of the procedures, equipment 
procurement and training necessary to perform the mandatory inspection. 
The FAA agrees. The effective date for the Final rule has been extended 
to 180 days after publication to allow sufficient time for the 
publication of the inspection procedures and for operators to prepare.

Request to Remove ``of This Chapter'' From Paragraph (e) of the 
Compliance Section

    One commenter requests that the FAA remove the statement ``of this 
chapter'' from the first sentence of paragraph (e) of this AD. The 
commenter feels that removing the statement will improve the clarity of 
the paragraph. The FAA agrees. The statement ``of this chapter'' has 
been removed from the first sentence of paragraph (e).

Economic Analysis

    No comments were received on the economic analysis contained in the 
proposed rules. The FAA has determined that the annual cost of 
complying with this AD does not create a significant economic impact on 
small entities.

Adoption of the Proposed Rule

    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 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.

Regulatory Impact

    This final 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 final 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 39-11124 (64 FR 
17958, April 13, 1999), and by adding a new airworthiness directive, 
Amendment 39-11697, to read as follows:

AD 2000-08-11  General Electric Company: Amendment 39-11697. Docket 
No. 98-ANE-41-AD. Supersedes AD 99-08-18, Amendment 39-11124.

Applicable Engines

    General Electric Company (GE) CF6-6, CF6-45, and CF6-50 series 
turbofan engines, installed on but not limited to Airbus Industrie 
A300 series, Boeing 747 series, and McDonnell Douglas DC-10 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 manufacturer's Time Limitations Section of the 
Instructions for Continued Airworthiness

[[Page 21638]]

(ICA), 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 instructions provided in the 
applicable manual provisions:

------------------------------------------------------------------------
                                                     Inspect per engine
       Part nomenclature         Part No.  (P/N)    shop manual chapter
------------------------------------------------------------------------
For CF6-6 Engines:
    Disk, Fan Rotor Stage One.  All..............  72-21-03 Paragraph
                                                    2.F. or Paragraph
                                                    2.A.B. Fluorescent-
                                                    Penetrant Inspect,
                                                    and 72-21-03
                                                    Paragraph 3 or 3.A.
                                                    Eddy Current
                                                    Inspection.
    Disk, HPT Rotor Stage One.  All..............  72-53-03 Paragraph 1.
                                                    Fluorescent-
                                                    Penetrant Inspect,
                                                    and 72-53-03
                                                    Paragraph 4. Eddy
                                                    Current Inspection
                                                    of the HPTR Disk Rim
                                                    Boltholes and 72-53-
                                                    03 Paragraph 5. Disk
                                                    Bore Area Eddy
                                                    Current Inspection.
    Disk, HPT Rotor Stage Two.  All..............  72-53-04 Paragraph 1.
                                                    Fluorescent-
                                                    Penetrant Inspect,
                                                    and Paragraph 4.
                                                    Eddy Current
                                                    Inspection of the
                                                    Stage 2 HPTR Disk
                                                    Rim Boltholes and 72-
                                                    53-04 Paragraph 5.
                                                    Eddy Current
                                                    Inspection of the
                                                    Stage 2 Disk Inner
                                                    Boltholes and 72-53-
                                                    04 Paragraph 6. Disk
                                                    Bore Area Eddy
                                                    Current Inspection
For CF6-45, CF6-50 Engines:
    Disk, Fan Rotor Stage One.  All..............  Task 72-21-03-230-051
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and Task
                                                    72-21-03-250-002-052
                                                    Manual Eddy Current
                                                    Inspection or 72-21-
                                                    03-250-003-053
                                                    Automated Eddy
                                                    Current Inspection.
    Disk, HPT Rotor Stage One.  All..............  Task 72-53-03-230-001-
                                                    059 Fluorescent-
                                                    Penetrant Inspect
                                                    Disk, and Task 72-53-
                                                    03-250-052 Eddy
                                                    Current Inspection
                                                    of the HPTR Stage 1
                                                    Rim Boltholes, and
                                                    Task 72-53-03-250-
                                                    060, Disk Bore Area
                                                    Eddy Current
                                                    Inspection.
    Disk, HPT Rotor Stage Two.  All..............  Task 72-53-04-230-001-
                                                    057 Fluorescent-
                                                    Penetrant Inspect
                                                    Disk, and Task 72-53-
                                                    04-250-053 Eddy
                                                    Current Inspection
                                                    of the HPTR Stage 2
                                                    Rim and/or Inner
                                                    Boltholes, and Task
                                                    72-53-04-250-060,
                                                    Disk Bore Area Eddy
                                                    Current Inspection.
------------------------------------------------------------------------

    (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 ICA.

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, 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)) must maintain records of 
the mandatory inspections that result from revising the Time Limits 
Section of the ICA 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 
engine shop manual changes are made and air carriers have modified 
their continuous airworthiness maintenance plans to reflect the 
requirements in the engine shop manuals.

    (f) This amendment becomes effective on October 23, 2000.

    Issued in Burlington, Massachusetts, on April 14, 2000.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 00-10158 Filed 4-21-00; 8:45 am]
BILLING CODE 4910-13-U