Airworthiness Directives; General Electric Company GE90 Series Turbofan Engines

[Federal Register Volume 64, Number 70 (Tuesday, April 13, 1999)]
[Rules and Regulations]
[Pages 17961-17962]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8859]



[[Page 17961]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-39-AD; Amendment 39-11123; AD 99-08-17]
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 adopts a new airworthiness directive (AD), that 
requires revisions to the manufacturer's Life Limits Section of the 
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. This amendment will also require an air carrier's approved 
continuous airworthiness maintenance program to incorporate these 
inspection procedures. This amendment is prompted by a Federal Aviation 
Administration (FAA) study of in-service events involving uncontained 
failures of critical rotating engine parts which indicated the need for 
improved inspections. The improved inspections are needed to identify 
those critical rotating parts with conditions, that if allowed to 
continue in service, could result in uncontained failures. 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 May 13, 1999.

ADDRESSES: The information contained in this AD may be examined at the 
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) to include an airworthiness 
directive (AD) that is applicable to General Electric Company (GE) GE90 
series turbofan engines was published in the Federal Register on July, 
28, 1998 (63 FR 40210). That action proposed to require, within the 
next 30 days after the effective date of this AD, revisions to Life 
Limits section of the manufacturer's Instructions for Continued 
Airworthiness (ICA) for GE GE90 series turbofan engines, and, for air 
carriers, the approved continuous airworthiness maintenance program. 
The manufacturer of GE90 series turbofan engines has provided the FAA 
with a detailed proposal that identifies critical life-limited rotating 
engine parts with the potential to hazard the airplane in the event of 
failure, along with instructions for enhanced, focused inspection 
methods. These enhanced inspections will be conducted at piece-part 
opportunity, as defined in this AD, rather than specific inspection 
intervals.
    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.
    Two commenters ask that the FAA clarify the record keeping aspects 
of the mandatory inspections resulting from the required changes to the 
Original Equipment Manufacturer's manual and operator's continuous 
airworthiness maintenance program. These commenters state that the AD 
should be revised to clearly specify which types of maintenance records 
must be retained (i.e., inspection results, defect reporting 
requirements, date of performed maintenance, signature of the person 
performing the maintenance). These commenters believe that these 
revisions are necessary in order to avoid potential differences in 
interpretation between the air carriers and the FAA. The FAA concurs in 
part. Generally, record keeping requirements are addressed in other 
regulations and this AD does not change those requirements. In order to 
allow flexibility from operator to operator, the FAA does not agree 
that the AD itself specify the precise nature of the records that will 
result from the required changes to the manufacturer's manual and 
operator's maintenance program. The FAA has, however, revised Paragraph 
(e) of this AD to clarify record keeping aspects of the new mandatory 
inspections.
    Since the engines affected by this AD are operated only by major 
air carriers, and there are no US operators, this AD will not create 
any 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.
    The regulations adopted herein will 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 final 
rule does not have sufficient federalism implications to warrant the 
preparation of a Federalism Assessment.
    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 adding the following new 
airworthiness directive:

99-08-17  General Electric Company: Amendment 39-11123. Docket 98-
ANE-39-AD.

    Applicability: General Electric Company (GE) GE90-76B/-77B/-85B/
-90B/-92B series turbofan engines, installed on but not limited to 
Boeing 777 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

[[Page 17962]]

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:
    (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:

----------------------------------------------------------------------------------------------------------------
                                                                                      Inspect per engine manual
                Part nomenclature                           Part No (P/N)                      chapter
----------------------------------------------------------------------------------------------------------------
HPCR Stage 7 Disk...............................  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 72-31-07-250-
                                                                                     052, or 72-31-07-250-053).
HPT Rotor Interstage Seal.......................  All.............................  72-53-03-200-001-001
                                                                                     Fluorescent Penetrant
                                                                                     Inspection (subtask 72-53-
                                                                                     03-230-053).
----------------------------------------------------------------------------------------------------------------

    (2) For the purposes of these mandatory inspections, piece-part 
opportunity means:
    (i) The part is considered completely disassembled when done in 
accordance with the disassembly instructions in the engine 
manufacturer's maintenance 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 Life Limits Section of 
the manufacturer's ICA.
    (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 Manager, Engine Certification Office. 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector (PMI), who may add comments and then 
send it to the Manager, Engine Certification Office.

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

    (d) Special flight permits may be issued in accordance with 
Secs. 21.197 and 21.199 of the Federal Aviation Regulations (14 CFR 
21.197 and 21.199) to operate the aircraft to a location where the 
requirements of this AD can be accomplished.
    (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 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 May 13, 1999.

    Issued in Burlington, Massachusetts, on April 2, 1999.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 99-8859 Filed 4-12-99; 8:45 am]
BILLING CODE 4910-13-P

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