[Federal Register Volume 60, Number 70 (Wednesday, April 12, 1995)]
[Rules and Regulations]
[Pages 18540-18542]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-8712]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-ANE-37; Amendment 39-9192; AD 95-08-03]
Airworthiness Directives; General Electric Company CF6 Series
Turbofan Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule.
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SUMMARY: This amendment adopts a new airworthiness directive (AD),
applicable to General Electric Company (GE) CF6-45/-50 series turbofan
engines, that requires reduction of the low cycle fatigue (LCF)
retirement lives for certain high pressure turbine rotor (HPTR) stage 2
disks, and would provide a drawdown schedule for those affected parts
with reduced LCF retirement lives. This amendment is prompted by the
results of a refined life analysis performed by the manufacturer which
revealed minimum calculated LCF lives significantly lower than
published LCF retirement lives. The actions specified by this AD are
intended to prevent a LCF failure of the HPTR stage 2 disk, which could
result in an uncontained engine failure and damage to the aircraft.
DATES: Effective June 12, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of June 12, 1995.
ADDRESSES: The service information referenced in this AD 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 Federal Aviation Administration
(FAA), New England Region, Office of the Assistant Chief 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: Robert J. Ganley, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA [[Page 18541]] 01803-5299;
telephone (617) 238-7138; fax (617) 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 (GE) CF6-
45/-50 series turbofan engines was published in the Federal Register on
December 20, 1994 (59 FR 65513). That action proposed to require a
reduction of the published low cycle fatigue (LCF) retirement lives for
certain high pressure turbine rotor stage 2 disks, and would provide a
drawdown schedule for those affected disks with reduced LCF retirement
lives. If the Federal Aviation Administration (FAA) approved rework is
accomplished, the LCF retirement life may be increased to 8,750 or
9,700 cycles, depending on the cycles since new of the disk when the
rework is performed. The actions would be performed in accordance with
GE CF6-50 Service Bulletin No. 72-1069, dated September 12, 1994.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
Two commenters support the rule as proposed.
Since publication of the NPRM, the FAA has increased its estimate
of the average labor cost to $60 per work hour, and has revised the
economic analysis of this final rule accordingly.
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 as proposed with the changes
described previously. The FAA has determined that these changes will
not increase the scope of the AD.
The FAA estimates that 280 engines installed on aircraft of U.S.
registry will be affected by this AD, that it will take approximately
194 work hours per engine to accomplish the required actions, and that
the average labor rate is $60 per work hour. Required parts will cost
approximately $16,383 per engine. Based on these figures, the total
cost impact of the AD on U.S. operators is estimated to be $7,846,440.
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.
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 it 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.
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. App. 1354(a), 1421 and 1423; 49 U.S.C.
106(g); and 14 CFR 11.89.
39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
95-08-03 General Electric Company: Amendment 39-9192. Docket 94-
ANE-37.
Applicability: General Electric Company (GE) CF6-45/50 series
turbofan engines installed on but not limited to Airbus A300 series,
Boeing 747 series, and McDonnell Douglas DC-10 series aircraft.
Note: 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 use the authority provided in paragraph (e) to
request approval from the FAA. This approval may address either no
action, if the current configuration eliminates the unsafe
condition, or different actions necessary to address the unsafe
condition described in this AD. Such a request should include an
assessment of the effect of the changed configuration on the unsafe
condition addressed by this AD. In no case does the presence of any
modification, alteration, or repair remove any engine from the
applicability of this AD.
Compliance: Required as indicated, unless accomplished
previously.
To prevent a low cycle fatigue (LCF) failure of the high
pressure turbine rotor (HPTR) stage 2 disk, which could result in an
uncontained engine failure and damage to the aircraft, accomplish
the following:
(a) Remove from service HPTR stage 2 disks Part Numbers (P/N)
1474M49P04, 1474M49P05, 1474M49P06, 9045M35P15, 9045M35P17, and
9045M35P18, in accordance with the following:
(1) For disks that have accumulated less than 3,500 cycles since
new (CSN) on the effective date of this airworthiness directive
(AD), remove disk from service prior to accumulating 7,080 CSN.
(2) For disks that have accumulated 3,500 CSN or more, but less
than 7,080 CSN on the effective date of this AD, remove disk from
service prior to accumulating 7,080 CSN, or prior to accumulating
3,100 cycles in service (CIS) after the effective date of this AD,
whichever occurs later, but not to exceed 9,700 CSN.
(3) For disks which have accumulated 7,080 CSN or more on the
effective date of this AD, remove disk from service at the next
piece-part exposure, but not to exceed 9,700 CSN.
(b) Remove from service HPTR stage 2 disks P/N 9264M58P01,
9264M58P02, and 9264M58P03 prior to accumulating 7,080 CSN.
(c) This AD establishes the following new LCF retirement lives
which will be published in Chapter 5 of the CF6-50 Engine Task
Numbered Shop Manual, GEK 50481: 7,080 cycles for HPTR stage 2 disk
P/N 1474M49P04, 1474M49P05, 1474M49P06, 9045M35P15, 9045M35P17,
9045M35P18, 9264M58P01, 9264M58P02, and 9264M58P03.
(d) GE CF6-50 Service Bulletin (SB) No. 72-1069, dated September
12, 1994, describes an FAA-approved rework procedure for the
affected disks. Accomplishment of this rework increases the FAA-
approved LCF retirement life to 8,750 or 9,700 cycles, depending on
the CSN of the disk when the rework is performed.
(e) 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.
(f) 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.
(g) The actions required by this AD shall be done in accordance
with the following service bulletin:
[[Page 18542]]
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Document No. Pages Date
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GE CF6-50 SB No. 72-1069................ 1-18 Sept. 12, 1994.
Total Pages: 18
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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 Aircraft Engines, CF6
Distribution Clerk, Room 132, 111 Merchant Street, Cincinnati, OH
45246. Copies may be inspected at the FAA, New England Region, Office
of the Assistant Chief 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.
(g) This amendment becomes effective on June 12, 1995.
Issued in Burlington, Massachusetts, on March 31, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 95-8712 Filed 4-11-95; 8:45 am]
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