[Federal Register Volume 64, Number 70 (Tuesday, April 13, 1999)]
[Rules and Regulations]
[Pages 17958-17960]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 99-8860]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-41-AD; Amendment 39-11124; AD 99-08-18]
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 adopts a new airworthiness directive (AD), that 
requires revisions to the Time Limits Section of the manufacturer's 
Instructions for Continued Airworthiness (ICA) for General Electric 
Company (GE) CF6-6, CF6-45, and CF6-50 series turbofan engines to 
include required enhanced inspection of selected critical life-limited 
parts at each piece-part exposure. This amendment also requires 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

[[Page 17959]]

result in uncontained failures. 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: Effective May 13, 1999.

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) to include an airworthiness 
directive (AD) that is applicable to GE CF6-6, CF6-45, and CF6-50 
series turbofan engines was published in the Federal Register on July 
28, 1998 (63 FR 40213). That action proposed to require revisions to 
the Time Limits Section of the manufacturer's ICA for GE CF6-6, CF6-45, 
and CF6-50 series turbofan engines to include required enhanced 
inspection of selected critical life-limited parts at each piece-part 
exposure. That action also proposed to require 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.
    Five commenters note that some of the tasks/sub-tasks referenced in 
the proposed rule call out inspections beyond those identified as part 
of the enhanced inspection initiative (i.e. visual and dimensional 
inspection in addition to the intended inspections). The commenters 
recommend that the final rule be revised to reflect only those tasks or 
sub-tasks that contain the inspections that are intended to be mandated 
by the AD. The FAA concurs. The requested change is consistent with the 
enhanced inspection initiative. The manual temporary revisions have 
been revised to reflect only those tasks or sub tasks where the 
inspections to be mandated are located and the AD will reflect these 
changes.
    One commenter notes that the work hours stated in the preamble for 
the HPTR stage 1 and 2 disk inspections are less than their estimates 
and recommends that the final rule be revised to note 18 hours for the 
mandated inspections instead of 8 hours. The FAA does not agree. The 
work hour estimate that includes 3 hours for eddy current inspection 
and 5 hours for FPI for each HPTR disk, for a total of 16 hours for the 
2 HPTR disks, is believed to be accurate for a disk of average 
cleanliness, being inspected under typical shop conditions.
    No other comments were received on the economic analysis contained 
in the proposed rule. Based on that analysis, the FAA has determined 
that the annual per engine cost of $438 does not create a significant 
economic impact on small entities.
    Several 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. One commenter believes 
that paragraph (e) of the proposed AD is unclear and suggests that it 
be revised by eliminating the word ``or'' from the first sentence and 
beginning a second sentence with ``In lieu of the record. * * *'' Two 
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. 
And, one commenter states that the AD should clarify that there is no 
need for a special form to comply with the AD record keeping 
requirements. 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.
    One commenter requested that the FAA link the conduct of mandatory 
inspections with the subject part's removal from an engine either on-
wing or removed and in an overhaul shop. The FAA does not concur. 
Mandatory inspections are based on a single trigger, which is a part 
being completely disassembled using the engine shop manual instructions 
(piece-part opportunity), and are not dependent on an engine's state of 
installation. This AD mandates that the definition of piece-part 
opportunity appear in the mandatory section of each affected engine 
shop manual. This AD further mandates that an operator's continuous 
airworthiness maintenance program be modified to capture those engine 
shop manual changes.
    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 previously 
described.
    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.

[[Page 17960]]

Sec. 39.13  [Amended]

    2. Section 39.13 is amended by adding the following new 
airworthiness directive:

99-08-18  General Electric Company: Amendment 39-11124. Docket 98-
ANE-41-AD.

    Applicability: General Electric Company (GE) CF6-6, CF6-45, and 
CF6-50 series turbofan engines, installed on but not limited to 
Airbus 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:
    (a) Within the next 30 days after the effective date of this AD, 
revise the manufacturer's Time 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:

----------------------------------------------------------------------------------------------------------------
       Part nomenclature                Part No. (P/N)              Inspect per engine shop manual chapter
----------------------------------------------------------------------------------------------------------------
For CF6-6 Engines:
    Fan Rotor Disk, Stage 1....  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.
    High Pressure Turbine        All........................  72-53-03  Paragraph 1. Fluorescent-Penetrant
     Rotor, Stage 1 Disk.                                      Inspect, and 72-53-03 Paragraph 4. Eddy Current
                                                               Inspection of the HPTR Disk Rim Boltholes.
    High Pressure Turbine        All........................  72-53-04  Paragraph 1. Fluorescent-Penetrant
     Rotor, Stage 2 Disk.                                      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.
For CF6-45, CF6-50 Engines:
    Fan Rotor Disk, Stage 1....  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.
    High Pressure Turbine        All........................  Task 72-53-03-230-001-059 Fluorescent-Penetrant
     Rotor, Stage 1 Disk.                                      Inspect Disk, and Task 72-53-03-250-052 Eddy
                                                               Current Inspection of the HPTR Stage 1 Rim
                                                               Boltholes.
    High Pressure Turbine        All........................   Task 72-53-04-230-001-057 Fluorescent-Penetrant
     Rotor, Stage 2 Disk.                                      Inspect Disk, and Task 72-53-04-250-053 Eddy
                                                               Current Inspection of the HPTR Stage 2 Rim and/or
                                                               Inner 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 
engine manufacturer's Engine Shop 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 the Time 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 Engine 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 airplane 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 Time Limits section of the ICA and the air carrier's 
continuous airworthiness program. Alternately, certificated air 
carriers may establish an alternate 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 May 13, 1999.

    Issued in Burlington, Massachusetts, on April 2, 1999.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 99-8860 Filed 4-12-99; 8:45 am]
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