[Federal Register Volume 64, Number 194 (Thursday, October 7, 1999)]
[Proposed Rules]
[Pages 54591-54594]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-26211]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-39-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Company GE90 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 General Electric Company 
(GE) GE90 series turbofan engines, that currently requires revisions to 
the Life 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 critical life-limited parts for 
enhanced inspection. 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

[[Page 54592]]

Docket No. 98-ANE-39-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: 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:

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 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-39-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-39-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On April 2, 1999, the Federal Aviation Administration (FAA) issued 
airworthiness directive (AD) 99-08-17, Amendment 39-11123 (64 FR 17961, 
April 13, 1999), to require revisions to the Life Limits 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, GE has developed additional focused 
inspection procedures. This proposal would add additional parts that 
would require enhanced inspection at each piece-part exposure.

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 99-08-17 to add additional critical 
life-limited parts for enhanced inspection at each piece-part 
opportunity.

Economic Analysis

    The FAA estimates that 26 engines installed on airplanes of US 
registry would be affected by this proposed AD, and that the average 
labor rate is $60 per work hour. The FAA estimates that the fan disk 
bore eddy current inspection (ECI) would take 4 work hours. The total 
cost of the new fan disk bore inspections per engine would be 
approximately $240. The FAA estimates that approximately 7 parts would 
be exposed to the piece-part level per year; therefore, the total cost 
for the added bore ECI inspections is estimated to be $1,680 per year.
    The FAA estimates that the fan disk dovetail slot ultrasonic 
inspection (US) would take 6 work hours. The total cost of the new fan 
disk dovetail inspections per engine would be approximately $360. The 
FAA estimates that approximately 7 parts would be exposed to the piece-
part level per year; therefore, the total cost for the added dovetail 
slot US inspections is estimated to be $2,520 per year.
    The FAA estimates that the high pressure compressor (HPC) disk bore 
ECI would take 3 work hours. The total cost of the new HPC inspections 
per engine would be approximately $180. The FAA estimates that 
approximately 13 parts would be exposed to the piece-part level per 
year; therefore, the total cost for the added bore ECI inspections is 
estimated to be $2,340 per year.
    The FAA estimates that the high pressure turbine (HPT) component 
bore ECI would take 3 hours. The total cost of the new HPT inspections 
per engine would be approximately $180. The FAA estimates that 
approximately 48 parts would be exposed to the piece-part level per 
year; therefore, the total cost for the added bore ECI inspections is 
estimated to be $8,640 per year.
    The FAA estimates that the HPC component dovetail slot ECI 
inspection would take 3 work hours. The total cost of the new HPC 
component dovetail inspections per engine would be approximately $180. 
The FAA estimates that approximately 25 parts would be exposed to the 
piece-part level per year; therefore, the total cost for the added 
dovetail slot ECI inspections is estimated to be $4,500 per year.
    The FAA estimates that the HPC component bolthole ECI inspection 
would take 2 work hours. The total cost of the new HPC bolthole 
inspections per engine would be approximately $120. The FAA estimates 
that approximately 21 parts would be exposed to the piece-part level 
per year; therefore, the total cost for the added bolthole ECI 
inspections is estimated to be $2,520 per year.
    Six fluorescent penetrant inspections (FPI) that would be added by 
this proposed AD already exist in the engine manual and therefore there 
is no additional cost associated with these inspections.
    The total for all of the additional inspections is estimated to be 
$22,200 per year.

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

[[Page 54593]]

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

General Electric Company: 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 Life Limits 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:

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                                                                                     Inspect per engine manual
                     Part nomenclature                          Part No. (P/N)                chapter
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For GE90 Engines:
    HPCR, Disk, Stage 7...................................  All..................  72-31-07-200-001-001
                                                                                    Fluorescent Penetrant
                                                                                    Inspection (subtask 72-31-07-
                                                                                    230-051), and 72-31-07-200-
                                                                                    001-001 Eddy Current
                                                                                    Inspection (subtask 72-31-07-
                                                                                    250-051 or 72-31-07-230-052
                                                                                    or 72-31-07-230-053.
    HPTR, Interstage Seal.................................  All..................  72-53-03-200-001-001
                                                                                    Fluorescent Penetrant
                                                                                    Inspection (subtask 72-53-03-
                                                                                    230-053), 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 (subtask 72-21-03-
                                                                                    230-051), and 72-21-03-200-
                                                                                    001-001 Eddy Current, 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 (subtask 72-53-02-
                                                                                    160-051), 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 (subtask 72-53-04-
                                                                                    230-052), 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 (subtask 72-31-05-
                                                                                    230-051), 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 (subtask 72-31-06-
                                                                                    230-051), and 72-31-06-200-
                                                                                    001-001 Eddy Current
                                                                                    Inspection of the S2
                                                                                    Dovetail Slots.
    HPCR Seal, Compressor Discharge Pressure..............  All..................  72-31-09-200-001-001
                                                                                    Fluorescent Penetrant
                                                                                    Inspection (subtask 72-31-09-
                                                                                    230-051), and 72-31-09-200-
                                                                                    001-001 Eddy Current
                                                                                    Inspection of the Boltholes.
----------------------------------------------------------------------------------------------------------------

    (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 Life 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 (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 Life Limits 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

[[Page 54594]]

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.

    Issued in Burlington, Massachusetts, on September 30, 1999.
David A. Downey,
Assistant Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 99-26211 Filed 10-6-99; 8:45 am]
BILLING CODE 4910-13-P