AD 2001-10-07

[Federal Register Volume 66, Number 97 (Friday, May 18, 2001)]
[Rules and Regulations]
[Pages 27592-27597]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 01-12374]


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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 2001-NE-05-AD; Amendment 39-12233; AD 2001-10-07]
RIN 2120-AA64


Airworthiness Directives; General Electric Co. CF6-80C2 Turbofan 
Engines

AGENCY: Federal Aviation Administration, DOT.

ACTION: Final rule.

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SUMMARY: This amendment adopts a new airworthiness directive (AD), that 
is applicable to General Electric Co. (GE) CF6-80C2 turbofan engines 
with certain stage 1 high pressure turbine (HPT) rotor disks installed. 
This amendment requires initial and repetitive inspections of certain 
HPT rotor disks for cracks in the bottom of the dovetail slot. This 
amendment 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 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: Effective date June 18, 2001. The incorporation by reference of 
certain publications listed in the regulations is approved by the 
Director of the Federal Register as of June 18, 2001.

ADDRESSES: 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, 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: 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: A proposal to amend part 39 of the Federal 
Aviation Regulations (14 CFR part 39) to include an AD that is 
applicable to General Electric Co. (GE) CF6-80C2 turbofan engines with 
certain stage 1 HPT rotor disks installed was published in the Federal 
Register on March 12, 2001 (66 FR 14348). That action 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.

Comments

    Interested persons have been afforded an opportunity to participate 
in the making of this amendment. Due consideration has been given to 
the comments received.

Include Alert Service Bulletin Revision 1

    One commenter states that Table 1 should reference GE Alert Service 
Bulletin (ASB) CF6-80C2 72-A1024, Revision 1, dated November 3, 2000, 
as well as the original ASB issue.
    The FAA agrees. The inspection requirements in ASB Revision 1 are 
the equivalent of the inspection requirements of original issue ASB 
CF6-80C2 72-A1024, dated October 13, 2000. Reference to ASB CF6-80C2 
72-

[[Page 27593]]

A1024, Revision 1 has been added to the final rule.

Change Economic Impact To Reflect Labor Cost for Engines That Are Not 
Due for HPT Piece-Part Exposure

    Three commenters request that the economic impact include labor 
costs for engines in the shop, that would otherwise not require HPT 
piece-part exposure. The commenters state that not all engine shop 
visits (ESV's) (scheduled or unscheduled) require complete disassembly 
of the HPT rotor. One commenter states that their inventory has 77 HPT 
rotor stage 1 disks that will require the inspection proposed in the 
rule over the next year, and an additional 22 units that will require 
24 hours of labor to complete piece-part exposure of the HPT rotor that 
would otherwise have remained assembled during the shop visit. Another 
commenter estimated it would cost an additional $22,000 per year to 
complete the additional disassembly required to perform the 
inspections.
    The FAA agrees. After considering the information presented by 
commenters, the FAA revised the subject work hours in the labor cost 
impact information. The FAA estimates that approximately 75% of all 
engines introduced into a shop each year will have the HPT at piece-
part level. The remaining 25% would require additional work scope to 
obtain HPT rotor piece-part exposure. The economic impact is revised to 
include this additional cost.

Change Economic Impact To Reflect Parts and Labor Costs Per Year, Due 
to ``Check & Repair'' Engines

    One commenter requests that the economic impact include parts and 
labor costs per year, for ``Check & Repair'' engines that would be 
upgraded to heavy work scopes due to the ``Next Shop Visit'' provision 
of the proposed rule. The commenter states that engines, termed as 
``Check & Repair'' engines, which is on-average eight engines per year, 
would have to be upgraded to heavy work scopes due to the ``Next Shop 
Visit'' provision of the proposed rule. The commenter states that this 
is an additional $2,000,000 in parts and labor costs per year. The 
commenter does not provide a breakdown of the total cost, but suggests 
that the additional exemptions requested to the definition of ESV would 
minimize the exposure to ``Check & Repair'' increased work scope.
    The FAA partially agrees. The FAA's interpretation of a ``Check and 
Repair'' engine is one that is introduced into a shop to address a 
known problem, with a limited work scope. The commenter did not provide 
the breakdown in the stated cost for these engines. The FAA has already 
included two exemptions to the definition of ESV in the notice of 
proposed rulemaking (NPRM) to lessen the economic impact of these 
maintenance actions. Any additional exemptions would result in an 
unacceptable level of safety. Therefore, the FAA made no changes to the 
rule with respect to this request. However, the economic impact has 
been revised to include the cost of the additional work scope required 
by approximately 25% of the engines affected by this AD, that would not 
have completed HPT rotor piece-part disassembly otherwise, during their 
ESV.

Change Economic Impact To Include Disk Replacement Cost

    One commenter states that the economic impact in the NPRM did not 
include the $283,480 cost of a replacement disk when a disk is found 
unserviceable.
    The FAA disagrees. The economic impact section of the NPRM did, in 
fact, include the cost of a replacement disk, assuming an annual 
projected rate of disks found unserviceable during the inspection 
program.

Clarify Inspection Requirements for Disks With Zero Cycles-Since-New 
(CSN), at Time of Inspection Using GE ASB CF6-80C2 72-A1024

    One commenter requests that the inspection requirements for disks 
with zero CSN at the time of inspection and using ASB CF6-80C2 72-
A1024, be clarified. The commenter states the NPRM is unclear, but did 
not supply any supporting data.
    The FAA partially agrees. ASB CF6-80C2 72-A1024 was issued as an 
interim step for engines undergoing HPT overhaul during the development 
of, and prior to, the implementation of the eddy current inspection 
(ECI), as introduced in ASB CF6-80C2 72-A1026. Since ASB CF6-80C2 72-
A1024 was issued for shop use during HPT overhaul, the FAA expects 
there are no disks with zero CSN that were inspected per ASB CF6-80C2 
72-A1024. The FAA does not consider it necessary to identify disks with 
zero CSN, in particular with respect to inspection in accordance with 
ASB CF6-80C2 72-A1024. However, to help clarify disk inspection 
requirements, the FAA has changed the inspection requirement of Table 
1, row three, to exclude inspection of disks with zero CSN. 
Furthermore, the intent of the inspections in both ASB CF6-80C2 72-
A1024 and ASB CF6-80C2 72-A1026 is to detect cracks in the bottoms of 
the dovetail slots that have grown during engine service. The 
propagation occurs during accumulation of disk cycles. Potential cracks 
have not propagated in unused disks, therefore, inspections of unused 
disks do not mitigate the risk.

Clarify Inspection Requirements for Disks With Less Than 1,500 CSN

    One commenter states that the NPRM is unclear, and requests 
clarification of the required inspection for a disk that has less than 
1,500 CSN on the effective date of this AD, and is at piece-part 
condition after the effective date of this AD. The commenter speculates 
that the average Mean Time Between Shop Visit on the CF6-80C2 engine is 
less than approximately 3,500 CSN, and in some instances the Mean Time 
Between Shop Visit is less than 1,000 cycles.
    The FAA disagrees that clarification is required. If an HPT stage 1 
disk is at piece-part condition, this qualifies as an ESV according to 
the NPRM. Therefore, the disk satisfies the requirements for Table 1, 
paragraph 1, and must be inspected. The initial inspection of all disks 
is required to occur at the next ESV. Also, paragraph (c) of this AD 
clearly states that after the effective date of this AD, stage 1 HPT 
rotor disks with greater than zero CSN must not be installed until 
inspected. If the disk has 1,500 or fewer CSN on the effective date of 
this AD, this initial inspection must occur at the next ESV, but before 
the disk usage exceeds 5,000 CSN, regardless of whether or not another 
shop visit is anticipated before the disk reaches 5,000 CSN. The 
proposed compliance times of the rule considered ESV rates, while 
maintaining an acceptable level of safety. In determining the 
calculated risk levels, the engine shop visit cyclic distribution data 
was used in the statistical model.

Add Contact Information for Reporting Requirements

    Two commenters request that contact information such as telephone 
number, fax number, address, and e-mail address of the Engine 
Certification Manager be added to the Reporting Requirements Section of 
the final rule. The FAA agrees. The contact information is added to the 
final rule.

Change ``Next Engine Shop Visit'' to ``Any Engine Shop Visit''

    One commenter requests that the initial inspection be required at 
any shop visit, not to exceed 3,500 cycles-in-service for used disks, 
and not to exceed 5,000 CSN for new disks. No substantiating data was 
included with this comment. The reason for the

[[Page 27594]]

request was stated as airline operator convenience.
    The FAA disagrees. In determining the calculated risk levels, the 
ESV cyclic distribution data was used in the statistical model. From a 
calculated risk standpoint, specifying only cycles is not the same as 
specifying next shop visit not to exceed a certain number of cycles. 
The initial inspection intervals of next shop visit are based on the 
risk assessment of the entire fleet. The change requested by the 
commenter would result in an extension of the inspection intervals. 
Extensions to the inspection intervals would increase risks to an 
unacceptable level of safety.

Incorporate Additional Exemptions to Engine Shop Visit

    Four commenters request that paragraph (d)(2) of the Compliance 
section in the NPRM be changed to add other maintenance actions as 
exemptions to an ESV, to include the following, individually and in 
combination:
    Introduction of an engine into a shop solely for:
    <bullet> Removal or replacement of the stage 1 fan disk.
    <bullet> Replacement of the Turbine Rear Frame.
    <bullet> Replacement of the Accessory and/or Transfer Gearboxes.
    <bullet> Replacement of the fan forward case.
    One of the four commenters suggests that these proposed exemptions 
are to address quick turn-time maintenance actions, and that these 
quick turn-time maintenance actions would otherwise not require HPT 
rotor piece-part disassembly. Therefore, the commenter suggests that 
significant additional cost would result if the visits for these 
maintenance actions were not exempt. In addition, this commenter states 
that their experience shows the number of engines that fall into the 
proposed categories are limited, and therefore, the proposed exemptions 
for ESV's will have no significant detriment to the level of safety 
over the program. All four commenters recommend that the addition of 
these exemptions will be consistent with AD 99-24-15 (CF6 High Pressure 
Compressor (HPC) stage 3-9 Spool Inspection). One of the four 
commenters states that these ESV exemptions will minimize the 
operator's exposure during ``Check & Repair'' work scope shop visits.
    The FAA disagrees that additional ESV exemptions are appropriate 
for this rule, based on the severity of the potential unsafe condition. 
As one commenter cited, the FAA finds that the frequency of these 
proposed shop visit exemptions is very low. While the four commenters 
request consistency with the existing AD 99-24-15 (HPC stage 3-9 spool 
inspection), the FAA notes that the most recent HPC stage 3-9 spool 
inspection, AD 2000-16-12, contains no exemptions from the definition 
of shop visit. The NPRM allowed two exemptions to the definition of an 
ESV, while maintaining the necessary level of safety. The FAA made no 
changes to the rule. In addition, operators can submit a request for an 
alternate method of compliance or adjustment of the compliance time 
that provides an acceptable level of safety. The NPRM definition 
paragraph (d) is now paragraph (e) in this rule.

Incorporate an Additional Exemption in the Definition of Engine Shop 
Visit

    One commenter requests an additional exemption in the definition of 
ESV to include a maintenance action that will result in removal of the 
compressor stator lower case, without need to separate any other major 
flanges. The commenter has a single engine scheduled for removal for 
the HPC 3-9 spool inspection. During the shop visit, removal of the 
compressor stator lower case may arise to replace bushings. The 
commenter developed an approved method to remove the lower case after 
reinstalling the top case while the engine is in a horizontal position, 
without separating any major flanges.
    The FAA disagrees. This was the only request of this kind. As the 
rule is intended to cover the entire fleet, the FAA does not want to 
revise the AD based on one engine. For unique situations, operators can 
submit a request for an alternative method of compliance or adjustment 
of the compliance time that provides an acceptable level of safety. 
Therefore, the FAA made no changes to the rule.

Add a Row to Table 1 for Disks Already Inspected Per GE ASB CF6-80C2 
72-A1026

    One commenter requests that a row be added to Table 1 for disks 
already inspected in accordance with GE ASB CF6-80C2 72-A1026 before 
the effective date of this AD. The added row would state a compliance 
time of ``any number of CSN if the disk has been inspected using ASB 
CF6-80C2 72-A1026, dated January 17, 2001, before the effective date of 
this AD'', with an initial inspection that is ``not applicable'', and a 
repetitive inspection that is ``at each piece-part exposure''. The 
commenter provides no substantiating data.
    The FAA partially agrees. The FAA has been informed that 
approximately 20 disks from US operators have been inspected in 
accordance with ASB CF6-80C2 72-A1026, dated January 17, 2001, since 
that ASB's issuance. These disks have significant cycles-since-new, and 
do not require another inspection until next piece-part exposure. 
Therefore, Table 1 remains as-written and a paragraph has been added to 
the compliance section stating that, for a stage 1 HPT rotor disk that 
has been inspected 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, before the effective date of this AD, 
and had greater than zero cycles-since-new (CSN) at the time of 
inspection, inspect the disk at each piece-part exposure, and replace 
as necessary. In addition, operators can submit a request for an 
alternative method of compliance or adjustment of the compliance time 
that provides an acceptable level of safety.

Option To Perform Initial Inspection for Zero Cycle Disks

    One commenter requests an option to perform ASB CF6-80C2 72-A1026, 
dated January 17, 2001, for zero cycle disks prior to installation. The 
commenter does not provide technical justification. The commenter 
states that since GE does not offer an HPT stage 1 disk that is not 
affected by the proposed AD, all first-run engines and engines in which 
zero cycle disks are or will be installed, will be limited to 5,000 
CSN. Because the inspections cannot be performed on-wing or at engine-
level, the proposed rule will cause forced-engine removals and 
disassembly of the HPT for short range applications.
    The FAA disagrees. The intent of the inspection is to detect cracks 
in the bottoms of the dovetail slots that have grown during engine 
cyclic service. The propagation occurs during accumulation of disk 
cycles. Potential cracks have not propagated in unused disks, 
therefore, inspections of unused disks do not mitigate the risk. The 
greater the number of cycles accumulated, the greater the risk for 
fatigue-induced failure. Therefore, short haul operators or operators 
with fleets that accumulate a large number of cycles per year are more 
significantly at risk of disk failure.

Change Initial Inspection Threshold, Paragraph 1, of Table 1, for Disks 
With 1,500 or Fewer CSN

    One commenter requests a change in Table 1, paragraph (1), for 
disks with 1,500 or fewer CSN on the effective date of the AD, to 
change the initial inspection threshold from ``not to exceed 5,000 
CSN'' to ``not to exceed 5,000 CSN or 10,000 hours time-since-

[[Page 27595]]

new, whichever comes later.'' The commenter provided no technical 
substantiation. The commenter states that since all HPT stage 1 disks 
are affected by the proposed AD, and the inspections cannot be 
performed on-wing or at engine level, short range applications will 
cause forced-engine removals.
    The FAA disagrees. Specifying hours-since-new does not address the 
cyclic nature of the crack propagation. The intent of the inspection is 
to detect cracks in the bottoms of the dovetail slots that have 
propagated during engine cyclic service. Because the propagation is 
related to low-cycle fatigue, the propagation occurs during 
accumulation of disk cycles. The greater the number of cycles 
accumulated, the greater the risk for fatigue-induced failure. 
Therefore, short haul operators or operators with fleets that 
accumulate a large number of cycles per year are more significantly at 
risk of disk failure. Inspections according to the compliance times in 
this rule will maintain an acceptable level of safety. Therefore, the 
FAA made no changes to the rule.

Review Initial Eddy Current Inspection Data

    Two commenters request that the ``Next Shop Visit'' accomplishment 
schedule be reviewed by the FAA, GE, and the airlines, after 
substantial data has been collected from the initial eddy current 
inspections. The commenters note that each data point referenced in the 
discussion of the proposed rule refers to crack initiation due to 
handling damage. The commenters believe a timely review of the expanded 
data set resulting from the inspection program is necessary to confirm 
the proposed schedule ensures safety without placing an unwarranted 
burden on the operators.
    The FAA partially agrees. The FAA considers this rule to be an 
interim action. A timely review of the expanded data set resulting from 
the inspection program is appropriate. Additional inspection results 
will be considered to ensure that the actions and schedule provide an 
acceptable level of safety. While the rule requires that inspection 
rejects be reported to the FAA, it is recommended that operators comply 
with GE's request for all inspection results be sent to GE, regardless 
of pass or failure of the inspection. All data, including successes and 
failures, will be analyzed to evaluate the safety level, and risk of a 
future event. The subject of handling damage will be discussed in the 
next response.

Initial Inspection Exemption for New Disks Installed in Engines Since 
New

    Two commenters request that the hard time limits for initial 
inspections in Table 1, items 1 and 2, should not apply to new disks 
which have been installed in engines since new. The commenters reason 
that because new disks have not been repaired or handled, this should 
preclude the disks from incurring the damage referenced in the proposed 
rule.
    The FAA disagrees. It is possible to incur damage during any 
handling of the disk, such as during part manufacture, engine assembly, 
engine disassembly, and during engine overhaul. Recent data on a disk 
previously rejected by an overhaul shop for a fluorescent-penetrant 
inspection indication at a slot end broaching burr that had not been 
completely removed at manufacturing, was destructively evaluated. This 
burr was associated with a crack, which extended into the slot aft 
corner. The crack had not propagated from fatigue. While this disk did 
not have cracking in the slot bottom corner, this finding suggests that 
it is possible for a disk to have a manufactured burr-related crack as 
a potential root cause for this series of events. Based on this data, 
the FAA made no changes to the rule.

Change to Definition of Piece-Part Exposure

    The FAA has also changed the definition of piece-part exposure in 
paragraph (e) of the final rule. The proposal provided that a piece-
part exposure would be achieved by a complete disassembly performed in 
accordance with the engine manufacturer's manual. It is possible that 
some operators may disassemble the HPT rotor disk using their own 
manual. Therefore, to make clear that a complete disassembly performed 
in accordance with an FAA-approved manual other than the manual 
published by the engine manufacturer, would constitute a piece-part 
exposure of the HPT rotor disk, the FAA has added the phrase ``or other 
FAA-approved'' to paragraph (e)(1)(i) of the final rule.
    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.

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 will be affected by this AD. The FAA 
estimates that it will take approximately three work hours per engine 
to accomplish the required actions, and the average labor rate is $60 
per work hour. Required parts will 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. Also, based on information 
provided by NPRM commenters to the FAA, approximately 48 (25%) of the 
shop visits will require additional work scope because they would not 
otherwise have required HPT rotor piece-part disassembly. The FAA 
estimates it will take approximately 50 work hours per engine to 
accomplish the required additional work scope actions, and the average 
labor rate is $60 per work hour. Based on these figures, the total 
additional work scope labor cost will be approximately $144,000. Based 
on all of these figures, the total cost impact of the proposed AD on 
U.S. operators is estimated to be $745,340 per year.

Regulatory Impact

    This final rule 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 final rule. 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 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 final evaluation has 
been prepared for this action and it 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.

[[Page 27596]]

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 a new airworthiness directive 
to read as follows:

2001-10-07  General Electric Co.: Amendment 39-12233. Docket No. 
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 (g) 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

    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) For stage 1 HPT rotor disks that have been inspected prior 
to the effective date of this AD, 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 had 
greater than zero cycles-since-new (CSN) at the time of inspection, 
inspect the disk at each piece-part exposure, and replace as 
necessary.
    (b) For stage 1 HPT rotor disks not previously inspected, 
inspect the disk 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, and Table 1 of this AD, and replace if necessary, 
as follows:

    Table 1.--Compliance Times for Stage 1 HPT Rotor Disk Inspections
------------------------------------------------------------------------
 Stage 1 HPT Rotor Disk Cycles-
since-new (CSN) on the effective  Initial inspection      Repetitive
         date of this AD                                  inspections
------------------------------------------------------------------------
(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.
(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.
 ASB CF6-80C2 72-A1024, Revision   effective date of
 1, dated November 3, 2000, or     this AD.
 original ASB issue, dated
 October 13, 2000, before the
 effective date of this AD, and,
 if the disk had greater than
 zero CSN at the time of
 inspection.
------------------------------------------------------------------------

    (c) 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.
    (d) Thereafter, inspect the disk at each piece-part exposure, 
and replace if necessary.

Definitions

    (e) 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, or other FAA-approved 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

    (f) Report the results of inspections on all disks that equal or 
exceed the reject criteria of GE ASB CF6-80C2 72-A1026, dated 
January 17, 2001, within 5 calendar days of the inspection, to the 
Manager, Engine Certification Office, FAA, Engine and Propeller 
Directorate, 12 New England Executive Park, Burlington, MA 01803-
5299; telephone: (781) 238-7140; fax: (781) 238-7199. Reporting 
requirements have been approved by the Office of Management and 
Budget and assigned OMB control number 2120-0056. The following 
information must be included in the report:
    (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

    (g) 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

[[Page 27597]]

compliance with this airworthiness directive, if any, may be 
obtained from the ECO.

Special Flight Permits

    (h) 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.

Incorporation by Reference

    (i) The inspections must be done in accordance with GE ASB CF6-
80C2 72-A1026, dated January 17, 2001. 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, Ohio 
45215, telephone: (513) 672-8400, fax: (513) 672-8422. Copies 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.

Effective Date of This AD

    (j) This amendment becomes effective on June 18, 2001.

    Issued in Burlington, Massachusetts, on May 10, 2001.
Francis A. Favara,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 01-12374 Filed 5-17-01; 8:45 am]
BILLING CODE 4910-13-U