[Federal Register Volume 60, Number 35 (Wednesday, February 22, 1995)]
[Proposed Rules]
[Pages 9792-9794]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-4249]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 94-ANE-41]


Airworthiness Directives; General Electric Company CF6 Series 
Turbofan Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD) that is applicable to General Electric Company (GE) CF6-
80A series turbofan engines. This proposal would require an initial and 
repetitive on-wing eddy current inspection or an on-wing spot 
fluorescent penetrant inspection of the compressor rear frame (CRF) 
midflange for cracks, and replacement, if [[Page 9793]] necessary, with 
serviceable parts. This proposal would also require removal from 
service of certain CRF's as a terminating action to the on-wing 
inspection program. This proposal is prompted by a report of a CRF 
separation that resulted in a rejected takeoff. The actions specified 
by the proposed AD are intended to prevent a CRF separation, which 
could result in a rejected takeoff and damage to the aircraft.

DATES: Comments must be received by April 24, 1995.

ADDRESSES: Submit comments in triplicate to the Federal Aviation 
Administration (FAA), New England Region, Office of the Assistant Chief 
Counsel, Attention: Rules Docket No. 94-ANE-41, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from General Electric Aircraft Engines, CF6 Distribution 
Clerk, Room 132, 111 Merchant Street, Cincinnati, OH 45246. This 
information may be examined at the FAA, New England Region, Office of 
the Assistant Chief Counsel, 12 New England Executive Park, Burlington, 
MA.

FOR FURTHER INFORMATION CONTACT: Robert J. Ganley, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (617) 
238-7138; fax (617) 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 in triplicate 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 94-ANE-41.'' 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 Assistant Chief Counsel, 
Attention: Rules Docket No. 94-ANE-41, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    This proposed airworthiness directive (AD) is applicable to General 
Electric Company (GE) CF6-80A series turbofan engines. The Federal 
Aviation Administration (FAA) has received a report of a compressor 
rear frame (CRF) separation on a GE CF6-80A series turbofan engine that 
resulted in a rejected takeoff. The FAA has also received seventeen 
additional reports of CRF's found cracked in service. Investigation 
reveals that axial cracks initiate in the CRF midflange and propagate 
in fatigue due to a high peak mean stress found at the rib radius 
tangency point where the rib rises to form the CRF midflange lug. The 
high peak mean stress is a result of thermal and pressure loading of 
the CRF midflange. The cracks reach critical size, and may result in a 
CRF separation. CRF's with modified midflanges exist which decrease the 
peak mean stress, therefore reducing the chance of a crack initiating. 
This condition, if not corrected, could result in a CRF separation, 
which could result in a rejected takeoff and damage to the aircraft.
    The FAA has reviewed and approved the technical contents of GE CF6-
80A Service Bulletin (SB) No. 72-593, Revision 2, dated March 19, 1992, 
that describes procedures for the initial and repetitive on-wing eddy 
current inspection (ECI) and the on-wing spot fluorescent penetrant 
inspection (FPI).
    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 require an initial and repetitive on-wing ECI or on-
wing spot FPI of the CRF midflange for cracks, and replacement, if 
necessary, with serviceable parts. This proposal would also require 
removal from service of non-modified CRF's as a terminating action to 
the on-wing inspection program. The actions would be required to be 
accomplished in accordance with the service bulletin described 
previously.
    The FAA estimates that 81 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 85 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would cost approximately $20,644 per engine. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $2,085,264.
    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 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 
106(g); and 14 CFR 11.89. [[Page 9794]] 


Sec. 39.13  [Amended]

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

General Electric Company: Docket No. 94-ANE-41.

    Applicability: General Electric Company (GE) CF6-80A series 
turbofan engines installed on, but not limited to, Airbus A310 
series and Boeing 767 series aircraft.
    Compliance: Required as indicated, unless accomplished 
previously.
    To prevent a compressor rear frame (CRF) separation, which could 
result in a rejected takeoff and damage to the aircraft, accomplish 
the following:
    (a) Inspect CRF, Part Numbers (P/N) 9283M77G07, 9283M77G08, 
9283M77G09, 9283M77G11, 9283M77G14, 7283M77G15, 9283M77G16, 
9283M77G17, 9283M77G18, 9283M77G19, 1338M77G01, 1338M77G02, 
1338M77G03, 1338M77G04, 1338M77G05, and 1338M77G06, that have not 
accomplished the midflange rework or replacement in accordance with 
any revision level of GE CF6-80A Service Bulletin (SB) No. 72-600 or 
72-611, prior to the effective date of this AD, as follows:
    (1) Perform an on-wing eddy current inspection (ECI) or an on-
wing spot fluorescent penetrant inspection (FPI) of the CRF 
midflange for cracks in accordance with the Accomplishment 
Instructions and the schedule outlined in Table 1 of GE CF6-80A SB 
No. 72-593, Revision 2, dated March 19, 1992, or within 1,000 cycles 
in service since the last shop level FPI, whichever occurs later, 
after the effective date of this AD.
    (2) Thereafter, reinspect the CRF midflange for cracks in 
accordance with the Accomplishment Instructions and schedule 
outlined in Table 2 of GE CF6-80A SB No. 72-593, Revision 2, dated 
March 19, 1992.
    (3) Remove from service prior to further flight CRF's with 
cracked midflanges that exceed the on-wing serviceable limits 
specified in Table 2 of GE CF6-80A SB No. 72-593, Revision 2, dated 
March 19, 1992, and replace with a serviceable part.
    (b) Remove from service CRF's identified in paragraph (a) of 
this AD at the next piece-part exposure, or by December 31, 1996, 
whichever occurs earlier, and replace with a serviceable part. 
Removal and replacement of CRF's in accordance with this paragraph 
constitutes terminating action to the on-wing inspection 
requirements of paragraph (a) of this AD.
    (c) For the purpose of this AD, a serviceable part is defined as 
a CRF that has accomplished the midflange rework or replacement in 
accordance with any revision level of GE CF6-80A SB No. 72-600 or 
72-611.
    (d) 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. The 
request should be forwarded through an appropriate FAA Principal 
Maintenance Inspector, who may add comments and then send it to the 
Manager, Engine Certification Office.

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

    (e) 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.
    Issued in Burlington, Massachusetts, on February 14, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-4249 Filed 2-21-95; 8:45 am]
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