AD 2000-11-12

[Federal Register Volume 65, Number 114 (Tuesday, June 13, 2000)]
[Rules and Regulations]
[Pages 37009-37011]
From the Federal Register Online via the Government Publishing Office [<a href="http://www.gpo.gov">www.gpo.gov</a>]
[FR Doc No: 00-14017]



[[Page 37009]]

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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 98-ANE-32-AD; Amendment 39-11760; AD 2000-11-12]
RIN 2120-AA64


Airworthiness Directives; General Electric Company CF6-45/50 
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 
is applicable to General Electric Company CF6-45/50 series turbofan 
engines. This AD requires initial and repetitive inspections for cracks 
in the stage 14 high pressure compressor (HPC) disk lock slots, and 
removal from service of certain disks, at the first piece-part level or 
HPC rotor disassembly level exposure, after 6,000 cycles since new 
(CSN). This amendment is prompted by reports of stage 14 HPC disk lock 
slot cracks discovered during shop fluorescent penetrant inspections. 
The actions specified by this AD are intended to prevent stage 14 HPC 
disk failure, which could result in an uncontained engine failure and 
damage to the aircraft.

DATES: Effective date August 14, 2000.
    The incorporation by reference of certain publications listed in 
the rule is approved by the Director of the Federal Register as of 
August 14, 2000.

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 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: William S. Ricci, Aerospace Engineer, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 12 
New England Executive Park, Burlington, MA 01803-5299; telephone (781) 
238-7742, 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 General Electric Company CF6-45/50 
series turbofan engines was published in the Federal Register on 
October 26, 1999 (64 FR 57606). That action proposed to require initial 
and repetitive inspections for cracks in the stage 14 high pressure 
compressor (HPC) disk lock slots, and removal from service of certain 
disks, at the first piece-part level or HPC rotor disassembly level 
exposure, after 6,000 cycles since new (CSN).

Comments Received

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

Cost Impact

    Two comments suggest that the financial impact is not 
representative of the replacement cost of the disk since the disk is no 
longer in production or stocked and the replacement cost of the stage 
11-14 spool shaft is more than $250,000. The FAA does not agree. Over 
the course of the inspection program, the availabilty of HPC rear 
shafts, and not the availability of stage 14 disks, is expected to be 
the limiting factor, requiring the installation of the stage 11-14 
spool shaft. In addition, the estimate of economic impact was based on 
the lost life of the stage 14 disk only.

Reporting Period

    One comment suggests that the time limit for reporting the results 
of inspections that equal or exceed the reject criteria be increased 
from within five days of the inspection to within ten days of the 
inspection. The FAA does not agree. Based on the potential criticality 
of a reject finding, five days is considered reasonable and is 
consistent with reporting requirements in ADs dealing with other 
critical rotating parts. Carriers can make arrangements with inspection 
facilities to report reject findings directly to the FAA if reporting 
to the carrier first would cause a delay in reporting to the FAA. 
Reports can be made to the FAA by fax on weekends and holidays. The FAA 
has included the telephone and fax numbers for the ECO in paragraph (h) 
of the Compliance Section.

Consistent Wording

    One comment asks that the FAA use consistent wording with regard to 
the term ``rotor module level exposure.'' The FAA agrees. The term 
``rotor module level exposure'' has been changed to ``rotor disassembly 
level exposure'' in the Summary and in paragraphs (f) and (i) (1) of 
the Compliance Section.

Replacement of the Fan Forward Case

    One comment requests that the FAA add a provision for the 
definition of an engine shop visit to paragraph (i) for ``Introduction 
of an engine into a shop solely for replacement of the fan forward 
case.'' The FAA agrees. To be consistent with AD 99-24-15, the 3-9 
spool AD, paragraph (i)(3)(iv), ``Introduction of an engine into a shop 
solely for replacement of the fan forward case,'' has been inserted 
into the compliance section of this AD and the paragraph previously 
numbered (I) (3) (iv) has been renumbered (i)(3)(v).

Effective Date

    One comment notes that the effective date should be changed so that 
it is consistent with the schedule provided by the service bulletin. 
The FAA does not agree. The rulemaking process is a formal legal course 
of action that does not include provisions for coordinating effective 
dates with manufacturers' service bulletins.

Support of the AD as Written

    Three comments support the AD as written.

Conclusion

    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 Analysis

    There are approximately 1,538 engines of the affected design in the 
worldwide fleet. The FAA estimates that 460 engines installed on 
aircraft of U.S. registry would be affected by this proposed AD, that 
it would take approximately 22 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 $3,600 per engine. Based on 
these figures, the total cost impact of the proposed AD on U.S. 
operators is estimated to be $2,263,200.

Regulatory Impact

    This rule does not have federalism implications, as defined in 
Executive Order 13132, because it does 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

[[Page 37010]]

FAA has not consulted with state authorities prior to publication of 
this 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 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 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, 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:

2000-11-12  General Electric Company: Amendment 39-11760. Docket 98-
ANE-32-AD.

    Applicability: General Electric Company (GE) Model CF6-45/50 
series turbofan engines, installed on but not limited to Airbus 
Industrie A300 series, Boeing Company 747 series, and McDonnell 
Douglas Corporation 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 (j) 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 a stage 14 high pressure compressor (HPC) disk 
failure, which could result in uncontained engine failure and damage 
to the aircraft, accomplish the following:

Inspections

    (a) Perform initial inspections of HPC stage 14 disks, part 
numbers (P/N's) 9080M34P03, 9080M34P04, 9080M34P05 and 9349M91P04, 
with serial number (SN) prefixes GWN, MPO, RRY, and SNL, and disk 
SN's SNE00001 through SNE00017, and disk SN's SNE01101 through 
SNE01110, in accordance with paragraphs 2.A. through 2.B. of GE CF6-
50 ASB No. 72-A1144, dated March 19, 1998, or ASB No. 72-A1144, 
Revision 1, dated May 13, 1999, and the following schedule:
    (1) Inspect disks with 6,500 cycles since new (CSN) or less on 
the effective date of this AD before accumulating 9,800 CSN.
    (2) Inspect disks with more than 6,500 CSN on the effective date 
of this AD no later than the next engine shop visit (ESV) after the 
effective date of this AD or before accumulating an additional 3,300 
cycles-in-service (CIS) after the effective date of this AD, 
whichever occurs first.
    (b) Perform repetitive inspections of HPC stage 14 disks, P/N's 
9080M34P03, 9080M34P04, 9080M34P05 and 9349M91P04, with SN prefixes 
GWN, MPO, RRY, and SNL, and disk SN's SNE00001 through SNE00017, and 
disk SN's SNE01101 through SNE01110, in accordance with paragraphs 
2.A. through 2.B. of GE CF6-50 ASB No. 72-A1144, dated March 19, 
1998, or ASB No. 72-A1144, Revision 1, dated May 13, 1999, and the 
following schedule:
    (1) For disks with less than 9,800 CSN at the time of the last 
inspection, perform repetitive inspections no later than 9,800 CSN 
or before accumulating 3,300 cycles since last inspection (CSLI), 
whichever occurs later.
    (2) For disks with 9,800 CSN or greater at the time of the last 
inspection, perform repetitive inspections no later than 3,300 CSLI.
    (c) Perform initial inspections of HPC stage 14 disks, P/N's 
9080M34P03, 9080M34P04, 9080M34P05 and 9349M91P04 with SN prefixes 
SNG and SNE, except disk SN's SNE00001 through SNE00017 and SNE01101 
through SNE01110, in accordance with paragraphs 2.A. through 2.B. of 
GE CF6-50 ASB No. 72-A1144, dated March 19, 1998, or ASB No. 72-
A1144, Revision 1, dated May 13, 1999, and the following schedule:
    (1) Inspect disks with 4,200 CSN or less on the effective date 
of this AD before accumulating 7,500 CSN.
    (2) Inspect disks with more than 4,200 CSN but less than 9,000 
CSN on the effective date of this AD at the next ESV after the 
effective date of this AD, before accumulating an additional 3,300 
CIS after the effective date of this AD, or before accumulating 
11,000 CSN, whichever occurs first.
    (3) Inspect disks with 9,000 CSN or greater on the effective 
date of this AD, at the next ESV after the effective date of this 
AD, or before accumulating an additional 2,000 CIS after the 
effective date of this AD, whichever occurs first.
    (d) Perform repetitive inspections of HPC stage 14 disks, P/N's 
9080M34P03, 9080M34P04, 9080M34P05 and 9349M91P04 with SN prefixes 
SNG and SNE, except disk SN's SNE00001 through SNE00017 and SNE01101 
through SNE01110, in accordance with paragraphs 2.A. through 2.B. of 
GE CF6-50 ASB No. 72-A1144, dated March 19, 1998, or ASB No. 72-
A1144, Revision 1, dated May 13, 1999, and the following schedule:
    (1) For disks with less than 7,500 CSN at the time of the last 
inspection, perform repetitive inspections no later than 7,500 CSN 
or before accumulating 3,300 CSLI, whichever occurs later.
    (2) For disks with 7,500 CSN or greater at the time of the last 
inspection, perform repetitive inspections no later than 3300 CSLI.

Removal From Service

    (e) Remove from service prior to further flight stage 14 HPC 
disks that equal or exceed the reject criteria established by GE 
CF6-50 ASB 72-A1144, dated March 19, 1998, or ASB No. 72-A1144, 
Revision 1, dated May 13, 1999.
    (f) Remove from service, HPC stage 14 disks, P/N's 9080M34P03, 
9080M34P04, 9080M34P05 and 9349M91P04 with SN prefixes SNG and SNE, 
except disk SN's SNE00001 through SNE00017 and SNE01101 through 
SNE01110, with greater than 6,000 CSN after the effective date of 
this AD, at the next piece-part level exposure or at the next HPC 
rotor disassembly level exposure after the effective date of this 
AD.

Terminating Action

    (g) Replacement of the stage 14 HPC disk, P/N's 9080M34P03, 
9080M34P04, 9080M34P05, 9349M91P04, with a stage 11-14 spool shaft 
is terminating action for the inspection requirements of this AD.

Reporting Requirements

    (h) Report the results of inspections that equal or exceed the 
reject criteria within five days of the inspection to: Manager, 
Engine Certification Office, FAA, Engine and Propeller Directorate, 
12 New England Executive Park, Burlington, MA 01803-5299, telephone, 
(781) 238-7141, fax, (781) 238-7199. The following information must 
be included in the report:

(1) HPC Stage 14 rotor disk P/N,
(2) HPC Stage 14 rotor disk SN,
(3) HPC Stage 14 rotor disk CSN,
(4) HPC Stage 14 rotor disk CSLI, and
(5) Date and location of inspection.

Reporting requirements have been approved by the Office of 
Management and Budget (OMB) and assigned OMB control number 2120-
0056.

Definitions

    (i) For the purpose of this AD, the following definitions apply:
    (1) HPC Rotor disassembly occurs if any of the HPC Rotor bolted 
flange joints are separated, such as the Stage 2 joint to accomplish 
the Stage 3-9 Spool inspection.

[[Page 37011]]

    (2) Piece-part exposure is defined as disassembly and removal of 
the stage 14 disk from the HPC rotor structure, regardless of any 
blades, locking lugs, bolts or balance weights assembled to the 
disk.
    (3) An engine shop visit is defined as the introduction of an 
engine into a shop when a major engine flange is separated. The 
following maintenance actions are not considered engine shop visits 
for the purpose of this AD:
    (i) Introduction of an engine into a shop solely for removal or 
replacement of the Stage 1 Fan Disk;
    (ii) Introduction of an engine into a shop solely for 
replacement of the Turbine Rear Frame;
    (iii) Introduction of an engine into a shop solely for 
replacement of the Accessory Gearbox or Transfer Gearboxes;
    (iv) Introduction of an engine into a shop solely for 
replacement of the Fan Forward Case.
    (v) Introduction of an engine into a shop for any combination of 
exceptions specified in paragraphs (i)(3)(i) through (i)(3)(iv);

Alternative Methods of Compliance

    (j) 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 request 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.

Incorporation by Reference

    (k) The inspections shall be done in accordance with paragraphs 
2.A. through 2.B. of GE CF6-50 ASB No. 72-A1144, dated March 19, 
1998, or ASB No. 72-A1144, Revision 1, dated May 13, 1999, 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 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.

Special Flight Permit

    (l) 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.

Effective Date of This AD

    (m) This amendment becomes effective on August 14, 2000.

    Issued in Burlington, Massachusetts, on May 25, 2000.
Thomas A. Boudreau,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 00-14017 Filed 6-12-00; 8:45 am]
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