Airworthiness Directives; General Electric Company CF6-6, -45, - 50, -80A, and -80C2 Series Turbofan Engines

[Federal Register Volume 63, Number 208 (Wednesday, October 28, 1998)]
[Rules and Regulations]
[Pages 57583-57585]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 98-28535]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-52-AD; Amendment 39-10853; AD 98-22-06]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-6, -45, -
50, -80A, and -80C2 Series Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule; request for comments.

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SUMMARY: This amendment adopts a new airworthiness directive (AD) that 
is applicable to General Electric Company CF6-6, -45, -50, -80A, and -
80C2 series turbofan engines. This action requires, prior to further 
flight, an ultrasonic immersion inspection for cracks in stage 1 fan 
disks, and, if necessary, replacement with serviceable parts. This 
amendment is prompted by reports of cracked fan disks found during 
routine shop inspections on fan disks manufactured between late 1984/
early 1985. The actions specified in this AD are intended to prevent 
fan disk failure due to cracks, which could result in an uncontained 
engine failure and damage to the aircraft.

DATES: Effective November 23, 1998.
    The incorporation by reference of certain publications listed in 
the regulations is approved by the Director of the Federal Register as 
of November 23, 1998.
    Comments for inclusion in the Rules Docket must be received on or 
before December 28, 1998.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Regional 
Counsel, Attention: Rules Docket No. 98-ANE-52-AD, 12 New England 
Executive Park,

[[Page 57584]]

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.
    The service information referenced in this AD may be obtained from 
General Electric Company via Lockheed Martin Technology Services, 10525 
Chester Road, Suite C, Cincinnati, OH 45215; telephone (513) 672-8400, 
fax (513) 672-8422. This information may be examined at the FAA, New 
England Region, Office of the Regional Counsel, 12 New England 
Executive Park, Burlington, MA; or at the Office of the Federal 
Register, 800 North Capitol Street, NW., suite 700, Washington, DC.

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: The Federal Aviation Administration (FAA) 
has received reports of three stage 1 fan disks installed on General 
Electric Company (GE) CF6 series turbofan engines found cracked during 
routine shop inspections. The investigation revealed that these fan 
disks contained titanium impurities including hard alpha or other high 
density inclusions that can be introduced during the manufacturing 
process. Fatigue cracks can originate in the area of inclusions and 
propagate in service to disk failure. These fan disks were manufactured 
from ``older material,'' defined as triple melt titanium alloys made 
prior to late 1984/early 1985, when significant titanium melting, 
forging, and inspection process improvements were introduced. 
Approximately 90 fan disks manufactured from the older material remain 
unaccounted for at this time and may be introduced into service or be 
in service. Previous recommendations for immersion ultrasonic 
inspection by the manufacturer to the operators (via service bulletins, 
wires, etc.) have failed to identify the location or status of these 
disks. This condition, if not corrected, could result in fan disk 
failure due to cracks, which could result in an uncontained engine 
failure and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of the 
following GE Alert Service Bulletins (ASBs), that describe procedures 
for ultrasonic immersion inspection for cracks: CF6-6 ASB 72-A996, 
Revision 4, dated June 9, 1998, CF6-50 ASB 72-A988, Revision 6, dated 
August 25, 1998, CF6-80A ASB 72-A565, Revision 5, dated June 9, 1998, 
and CF6-80C2 ASB 72-A478, Revision 4, dated June 9, 1998.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other engines of the same type design, this AD is 
being issued to prevent fan disk failure. This AD requires, prior to 
further flight, an ultrasonic immersion inspection for cracks in stage 
1 fan disks, and, if necessary, replacement with serviceable parts. The 
actions are required to be accomplished in accordance with the ASBs 
described previously.
    Since a situation exists that requires the immediate adoption of 
this regulation, it is found that notice and opportunity for prior 
public comment hereon are impracticable, and that good cause exists for 
making this amendment effective in less than 30 days.

Comments Invited

    Although this action is in the form of a final rule that involves 
requirements affecting flight safety and, thus, was not preceded by 
notice and an opportunity for public comment, comments are invited on 
this rule. Interested persons are invited to comment on this rule by 
submitting such written data, views, or arguments as they may desire. 
Communications should identify the Rules Docket number and be submitted 
in triplicate to the address specified under the caption ADDRESSES. All 
communications received on or before the closing date for comments will 
be considered, and this rule may be amended in light of the comments 
received. Factual information that supports the commenter's ideas and 
suggestions is extremely helpful in evaluating the effectiveness of the 
AD action and determining whether additional rulemaking action would be 
needed.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the rule that might 
suggest a need to modify the 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 that 
summarizes each FAA-public contact concerned with the substance of this 
AD 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-52-AD.'' The postcard will be date stamped and 
returned to the commenter.
    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.
    The FAA has determined that this regulation is an emergency 
regulation that must be issued immediately to correct an unsafe 
condition in aircraft, and is not a ``significant regulatory action'' 
under Executive Order 12866. It has been determined further that this 
action involves an emergency regulation under DOT Regulatory Policies 
and Procedures (44 FR 11034, February 26, 1979). If it is determined 
that this emergency regulation otherwise would be significant under DOT 
Regulatory Policies and Procedures, a final regulatory evaluation will 
be prepared and placed in the Rules Docket. A copy of it, if filed, 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, Incorporation by 
reference, 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:

98-22-06  General Electric Company: Amendment 39-10853. Docket 98-
ANE-52-AD.

    Applicability: General Electric Company (GE) CF6-6, -45, -50, -
80A, and -80C2 series turbofan engines, with stage 1 fan disks 
installed, identified by serial numbers (S/Ns) in the following GE 
Alert Service Bulletins (ASBs): CF6-6 ASB 72-A996, Revision 4, dated 
June 9, 1998; CF6-50 ASB 72-A988, Revision 6, dated August 25, 1998; 
CF6-80A ASB 72-A565, Revision 5, dated June 9, 1998; and CF6-80C2 
ASB 72-A478, Revision 4, dated June 9, 1998. These engines are

[[Page 57585]]

installed on but not limited to Boeing 747 and 767, Airbus A300 and 
A310, McDonnell Douglas DC-10 and McDonnell Douglas MD-11 series 
aircraft.

    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 (b) 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 fan disk failure due to cracks, which could result in 
an uncontained engine failure and damage to the aircraft , 
accomplish the following:
    (a) Prior to further flight, perform an ultrasonic immersion 
inspection for cracks of affected stage 1 fan disks, and, if 
necessary, replace with serviceable parts, as follows:
    (1) For GE CF6-6 series engines, in accordance with GE CF6-6 ASB 
72-A996, Revision 4, dated June 9, 1998.
    (2) For GE CF6-45 and -50 series engines, in accordance with GE 
CF6-50 ASB 72-A988, Revision 6, dated August 25, 1998.
    (3) For GE CF6-80A series engines, in accordance with CF6-80A 
ASB 72-A565, Revision 5, dated June 9, 1998.
    (4) For GE CF6-80C2 series engines, in accordance with CF6-80C2 
ASB 72-A478, Revision 4, dated June 9, 1998.
    (5) Remove from service cracked fan disks and replace with 
serviceable parts.
    (b) 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, 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.

    (c) 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 aircraft to a location where 
the requirements of this AD can be accomplished.
    (d) The actions required by this AD shall be done in accordance 
with the following GE ASBs:

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                Document No.                    Pages       Revision                      Date
----------------------------------------------------------------------------------------------------------------
CF6-6 ASB 72-A996..........................         1-13            4  June 9, 1998.
Total pages: 13
CF6-50 ASB 72-A988.........................         1-13            6  August 25, 1998.
Total pages: 13
CF6-80A ASB 72-A565........................         1-13            5  June 9, 1998.
Total pages: 13
CF6-80C2 ASB 72-A478.......................         1-13            4  June 9, 1998.
Total pages: 13.
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This incorporation by reference was approved by the Director of the 
Federal Register in accordance with 5 U.S.C. 552(a) and 1 CFR part 
51. Copies may be obtained from General Electric Company via 
Lockheed Martin Technology Services, 10525 Chester Road, Suite C, 
Cincinnati, OH 45215; telephone (513) 672-8400, fax (513) 672-8422. 
Copies may be inspected at the FAA, New England Region, Office of 
the Regional Counsel, 12 New England Executive Park, Burlington, MA; 
or at the Office of the Federal Register, 800 North Capitol Street, 
NW., suite 700, Washington, DC.
    (e) This amendment becomes effective on November 23, 1998.

    Issued in Burlington, Massachusetts, on October 19, 1998.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification 
Service.
[FR Doc. 98-28535 Filed 10-27-98; 8:45 am]
BILLING CODE 4910-13-U

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