[Federal Register Volume 66, Number 48 (Monday, March 12, 2001)]
[Proposed Rules]
[Pages 14348-14350]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 01-5496]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-05-AD]
RIN 2120-AA64


Airworthiness Directives; General Electric Co. CF6-80C2 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-
80C2 turbofan engines with certain stage 1 high pressure turbine (HPT) 
rotor disks installed. This proposal would require initial and 
repetitive inspections of certain HPT rotor disks for cracks in the 
bottom of the dovetail slot. This proposed AD is prompted by a report 
of an uncontained failure of an engine during a high-power ground run 
for maintenance. The actions specified by this proposed AD are intended 
to detect cracks in the bottoms of the dovetail slots that could 
propagate to failure of the disk and cause an uncontained engine 
failure.

DATES: Comments must be received by April 11, 2001.

ADDRESSES: Submit comments to the Federal Aviation Administration 
(FAA), New England Region, Office of the Regional Counsel, Attention: 
Rules Docket No. 2001-NE-05-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.
    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, Ohio 45215, telephone (513) 672-
8400, fax (513) 672-8422. This information may be examined at the 
Federal Aviation Administration (FAA), New England Region, Office of 
the Regional Counsel,

[[Page 14349]]

12 New England Executive Park, Burlington, MA.

FOR FURTHER INFORMATION CONTACT: Ann Mollica, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone: 781-
238-7740, 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 action 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 action must submit a self-addressed, 
stamped postcard on which the following statement is made: ``Comments 
to Docket Number 2001-NE-05-AD.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRM's

    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. 2001-NE-05-AD, 12 New England Executive 
Park, Burlington, MA 01803-5299.

Discussion

    On September 22, 2000, a Boeing 767-2B7(ER), equipped with GE CF6-
80C2B2 model engines, experienced an uncontained failure of the stage 1 
HPT rotor disk during a high-power ground run for maintenance. The 
investigation of the failure has indicated that the stage 1 HPT rotor 
disk separation was the result of a crack that initiated in the aft 
corner radius of the bottom of a dovetail slot. The FFA had received 
two additional reports of stage 1 HPT rotor disks that were found to 
have cracks in the aft corner radius of the bottom of the dovetail 
slots. The cracks were found during shop visits in 1996 and 1999. In 
both cases, the cracks initiated from handling type damage to the aft 
corner radius of the bottoms of the dovetail slots. The actions 
specified by this proposed AD are intended to detect cracks in the 
bottoms of the dovetail slots that could propagate to failure of the 
disk and cause an uncontained engine failure.

Manufacturer's Service Information

    The FAA has reviewed and approved the technical contents of GE 
alert service bulletin (ASB) CF6-80C2 72-A1026, dated January 17, 2001, 
that describes procedures for fluorescent penetrant, visual and eddy 
current inspections of the bottoms of the dovetail slots.

Differences Between the Manufacturer's Service Information and This 
AD

    Although the GE ASB CF6-80C2 72-A1026, dated January 17, 2001, only 
requires a one-time inspection, the FAA has determined that repetitive 
inspections are required to achieve an acceptable level of safety.

Determination of an Unsafe Condition

    Since an unsafe condition has been identified that is likely to 
exist or develop on other GE CF6-80C2 engines of the same type design, 
this AD is being proposed to detect cracks in the bottoms of the 
dovetail slots that could propagate to failure of the disk and cause an 
uncontained engine failure. For stage 1 HPT rotor disks with greater 
than 1,500 cycles-since-new (CSN), this proposed AD would require an 
initial inspection at the next shop visit before accumulating 3,500 
cycles-in-service (CIS) after the effective date of this AD. For disks 
with 1,500 CSN or fewer on the effective date of this AD, this proposed 
AD would require an initial inspection at the next shop visit before 
accumulating 5,000 CSN. This proposed AD would also require repetitive 
inspections at piece-part opportunity, and if cracked, replacement with 
a serviceable disk. The actions would be done in accordance the service 
bulletin described previously.

Economic Impact

    There are approximately 2,954 engines of the affected design in the 
worldwide fleet. The FAA estimates that 637 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD. The 
FAA estimates that it would take approximately 3 work hours per engine 
to accomplish the proposed actions, and the average labor rate is $60 
per work hour. Required parts would cost approximately $283,480 per 
engine. The FAA also estimates that approximately 191 engines per year 
will have shop visits, and that of those 191 engines, approximately two 
disks per year will have to be replaced. Based on these figures, the 
total cost impact of the proposed AD on U.S. operators is estimated to 
be $601,340 per year.

Regulatory Impact

    This proposal does not have federalism implications, as defined in 
Executive Order 13132, because it would not have a substantial direct 
effect 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. Accordingly, 
the FAA has not consulted with state authorities prior to publication 
of this proposal. 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. 106(g), 40113, 44701.


Sec. 39.13  [Amended]

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


[[Page 14350]]


General Electric Co.: Docket 2001-NE-05-AD.
    Applicability: This airworthiness directive (AD) is applicable 
to General Electric Company (GE) CF6-80C2 series turbofan engines 
with stage 1 high pressure turbine (HPT) rotor disks, part numbers 
(P/N's) 1531M84G02, 1531M84G06, 1531M84G08, 1531M84G10, 9392M23G10, 
9392M23G12, 9392M23G21, and 1862M23G01 installed. These engines are 
installed on, but not limited to Airbus Industrie A300 and A310 
series, Boeing 747 and 767 series, and McDonnell Douglas MD-11 
series airplanes.

    Note 1: This 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 (f) of 
this AD. The request should include an assessment of the effect of 
the modification, alternation, 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: Compliance with this AD is required as indicated 
below, unless already done.
    To detect cracks in the bottoms of the dovetail slots that could 
propagate to failure of the disk and cause an uncontained engine 
failure, perform the following inspections:
    (a) Inspect the stage 1 HPT rotor disk in accordance with 3.A(1) 
through 3.C.(10)(i) of the Accomplishment Instructions of GE alert 
service bulletin (ASB) CF6-80C2 72-A1026, dated January 17, 2001, 
and Table 1 of this AD, and replace if necessary, as follows:

       Table 1.--Compliance Times for Stage 1 HPT Disk Inspections
------------------------------------------------------------------------
 Stage 1 HPT rotor disk cycles-
since-new (CSN) on the effective  Initial inspection      Repetitive
         date of this AD                                  inspection
------------------------------------------------------------------------
(1) 1,500 CSN or fewer..........  At the next engine  At each piece-part
                                   shop visit (ESV)    exposure.
                                   after the
                                   effective date of
                                   this AD, but not
                                   to exceed 5,000
                                   CSN.
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(2) More than 1,500 CSN.........  At the next ESV     At each piece-part
                                   after the           exposure.
                                   effective date of
                                   this AD, but not
                                   to exceed 3,500
                                   cycles-in-service
                                   (CIS) after the
                                   effective date of
                                   this AD.
------------------------------------------------------------------------
(3) Any number of CSN if the      At the next ESV     At each piece-part
 disk has been inspected using     after the           exposure.
 CF6-80C2 72-A1024, dated          effective date of
 October 13, 2000, before the      this AD.
 effective date of this AD.
------------------------------------------------------------------------

    (b) After the effective date of this AD, do not install any 
stage 1 HPT rotor disk with greater than zero CSN until it has been 
inspected in accordance with 3.A.(1) through 3.C.(10)(i) of the 
Accomplishment Instructions of GE ASB CF6-80C2 72-A1026, dated 
January 17, 2001.
    (c) Thereafter, inspect the disk at each piece-part exposure, 
and replace if necessary.

Definitions

    (d) The following definitions apply for this AD:
    (1) Piece-part exposure means the stage 1 HPT rotor disk is 
considered completely disassembled as follows:
    (i) When done in accordance with the disassembly instructions in 
the engine manufacturer's Engine Manual, AND
    (ii) the disk has accumulated more than 100 CIS since the last 
piece-part opportunity inspection, if the disk was not damaged or 
related to the cause for its removal from the engine.
    (2) An ESV is defined as the induction of an engine into a shop 
where the separation of a major engine flange will occur after the 
effective date of this AD. The following actions, either separately 
or in combination, are not considered ESV's for the purpose of this 
AD.
    (i) Induction of an engine into a shop solely for removal of the 
upper compressor stator case for airfoil maintenance.
    (ii) Induction of an engine into a shop solely for the module 
level inspection of the high pressure compressor rotor 3-9 spool.

Reporting Requirements

    (e) Report the following information on all disks that equal or 
exceed the reject criteria of GE ASB CF6-80C2 72-A1026, within 5 
calendar days of the inspection, to the Manager, Engine 
Certification Office. Reporting requirements have been approved by 
the Office of Management and Budget and assigned OMB control number 
2120-0056.

(1) Engine model in which the stage 1 HPT rotor disk was installed, 
AND
(2) Disk P/N, AND
(3) Disk serial number, AND
(4) CSN on the disk, AND
(5) Cycles-since-last-inspection, AND
(6) Date and location of the inspection

Alternative Methods of Compliance

    (f) 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 (ECO). 
Operators shall submit their requests through an appropriate FAA 
Principal Maintenance Inspector, who may add comments and then send 
it to the Manager, 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.

Special Flight Permits

    (g) 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.

    Issued in Burlington, Massachusetts, on February 27, 2001.
David A. Downey,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-5496 Filed 3-9-01; 8:45 am]
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