[Federal Register Volume 65, Number 79 (Monday, April 24, 2000)]
[Rules and Regulations]
[Pages 21642-21644]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 00-10157]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-39-AD; Amendment 39-11696; AD 2000-08-10]
RIN 2120-AA64


Airworthiness Directives; General Electric Company GE90 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 General Electric Company GE90 series 
turbofan engines, that currently requires revisions to the 
Airworthiness Limitations Section (ALS) 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 adds additional critical life-limited 
parts for enhanced inspection. This amendment is prompted by additional 
focused inspection procedures for other critical life-limited rotating 
engine parts 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 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) 
238-7134, fax (781) 238-7199.

SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) by superseding (AD) 990817, 
Amendment 3911123 (64 FR 17961), that is applicable to General Electric 
Company GE90 series turbofan engine was published in the Federal 
Register on October 7, 1999 (64 FR 54591). That action proposed to 
require revisions to the Airworthiness Limitations Section of the 
manufacturer's Instructions for Continued Airworthiness (ICA) for 
General Electric Company (GE) GE90 series turbofan engines to include 
required enhanced inspection of selected critical life-limited parts at 
each piece-part exposure.

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 five comments received.

``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 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.

``Life Limits'' vs. ``Airworthiness Limitations'' Sections

    One commenter recommends replacing references to the ``Life 
Limits'' section with references to the ``Airworthiness Limitations'' 
section because Chapter 5 now contains two subsets, 05-11 for Life 
Limits, and 05-21 for the mandatory inspection. The FAA agrees. The 
Final Rule references the ``Airworthiness Limitations'' section instead 
of the ``Life Limits'' section.

Task Numbers and Inspection Descriptions

    One commenter recommends that 2nd level task numbers and inspection 
descriptions be used instead of the subtask numbers to ensure that all 
appropriate preparatory steps (e.g. cleaning) are included in the 
mandatory inspection. The FAA agrees. The Final Rule has been revised 
accordingly to ensure that all appropriate preparatory steps (e.g. 
cleaning) are included in the mandatory inspection.

Effectivity Date

    Two commenters request that the AD's effectivity date 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 effectivity 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.

Removal of ``of This Chapter'' From Paragraph (e) of the Compliance 
Section

    The statement ``of this chapter'' has been removed from the first 
sentence of paragraph (e) to improve the clarity of the paragraph.

[[Page 21643]]

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.
    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 39-11123 (64 FR 
17961, April 13, 1999), and by adding a new airworthiness directive, 
Amendment 39-11696 to read as follows:

AD 2000-08-10  General Electric Company: Amendment 39-11696. Docket 
No. 98-ANE-39-AD. Supersedes AD 99-08-17, Amendment 39-11123.

    Applicability: General Electric Company (GE) GE90-76B/ -77B/ -
85B/ -90B/ -92B series turbofan engines, installed on but not 
limited to Boeing 777 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 Airworthiness Limitations Section of the 
Instructions for Continued Airworthiness (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)       manual chapter
------------------------------------------------------------------------
For GE90 Engines:
    HPCR, Disk, Stage 7.......  All..............  72-31-07-200-001-001
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    31-07-200-001-001
                                                    Eddy Current
                                                    Inspection of the
                                                    Rim Boltholes.
    HPTR, Interstage Seal.....  All..............  72-53-03-200-001-001
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    53-03-200-001-001
                                                    Eddy Current
                                                    Inspection of the
                                                    Bore.
    Fan Disk, Stage 1.........  All..............  72-21-03-200-001-001
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    21-03-200-001-001
                                                    Eddy Current
                                                    Inspection of the
                                                    Bore, and 72-21-03-
                                                    200-001-001
                                                    Ultrasonic
                                                    Inspection of
                                                    Dovetail Slots.
    HPTR Disk, Stage 1........  All..............  72-53-02-200-001-002
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    53-02-200-001-002
                                                    Eddy Current
                                                    Inspection of the
                                                    Bore.
    HPTR Disk, Stage 2........  All..............  72-53-04-200-001-004
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    53-04-200-001-004
                                                    Eddy Current
                                                    Inspection of the
                                                    Bore.
    HPCR Disk, Stage 1........  All..............  72-31-05-200-001-001
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    31-05-200-001-001
                                                    Eddy Current
                                                    Inspection of the
                                                    Bore, and 72-31-05-
                                                    200-001-001 Eddy
                                                    Current Inspection
                                                    of the Dovetail
                                                    Slots.
    HPCR Spool, Stage 2-6.....  All..............  72-31-06-200-001-001
                                                    Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    31-06-200-001-001
                                                    Eddy Current
                                                    Inspection of the S2
                                                    Dovetail Slots.
    HPCR Seal, Compressor       All..............  72-31-09-200-001-001
     Discharge Pressure.                            Fluorescent
                                                    Penetrant
                                                    Inspection, and 72-
                                                    31-09-200-001-001
                                                    Eddy Current
                                                    Inspection of the
                                                    Boltholes.
------------------------------------------------------------------------


[[Page 21644]]

    (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 Airworthiness 
Limitations 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 (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)) must maintain records of 
the mandatory inspections that result from revising the 
Airworthiness Limitations Section of the Instructions for Continuous 
Airworthiness (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 manual changes are made and air carriers have modified their 
continuous airworthiness maintenance plans to reflect the 
requirements in the engine 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. 00-10157 Filed 4-21-00; 8:45 am]
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