[Federal Register Volume 59, Number 77 (Thursday, April 21, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 94-7785]
[[Page Unknown]]
[Federal Register: April 21, 1994]
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DEPARTMENT OF TRANSPORTATION
14 CFR Part 39
[Docket No. 91-ANE-45; Amendment 39-8862; AD 94-07-04]
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) CF6-80A series turbofan
engines, that requires an inspection for cracks in the stage 1 high
pressure turbine (HPT) disk rim bolt holes. This amendment is prompted
by a report of an uncontained stage 1 HPT disk failure, which resulted
in an aborted takeoff. The actions specified by this AD are intended to
prevent an uncontained stage 1 HPT disk failure, which could result in
an inflight engine shutdown, aborted takeoff, or damage to the
aircraft.
DATES: Effective May 23, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 23, 1994.
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 01803-5299; telephone (617)
238-7138; fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: A proposal to amend part 39 of the Federal
Aviation Regulations to include an airworthiness directive (AD) that is
applicable to General Electric Company (GE) CF6-80A series turbofan
engines was published as a notice of proposed rulemaking (NPRM) in the
Federal Register on January 9, 1992 (57 FR 857). That action proposed
to require a one-time inspection for cracks in the stage 1 high
pressure turbine (HPT) disk rim bolt holes in accordance with GE
Commercial Engine Service Memorandum (CESM) No. 27, dated September 27,
1991.
Since the issuance of that NPRM, GE issued CF6-80A Service Bulletin
(SB) No. 72-604, Revision 3, dated April 8, 1993, which revised the
inspection program based on additional investigation findings on the
reported disk failure. A Supplemental NPRM was published in the Federal
Register on November 3, 1993 (58 FR 58667), which proposed to require
an inspection for cracks in the stage 1 HPT disk rim bolt holes in
accordance with the revised inspection program described in GE CF6-80A
SB No. 72-604, Revision 3, dated April 8, 1993.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. Due consideration has been given to
the comments received.
One commenter supports the rule as proposed.
One commenter states that previous revision levels of GE CF6-80A SB
No. 72-604, Revision 3, dated April 8, 1993, should be incorporated by
reference. The FAA does not concur. Compliance paragraph (d) of the
proposed rule already addresses inspections performed in accordance
with these previous revision levels.
One commenter states that the AD should not refer to a specific
revision of the GE SB, but instead, use the phrase ``latest revision''
when citing the SB. The FAA does not concur. When incorporating a
manufacturer's SB into an AD, the actual revision level and issue date
of the SB must be specified. The FAA can not review and approve the
technical contents of a document that has not yet been issued. Future
revisions to a SB incorporated into an AD that do not substantively
change the compliance requirements or times, may carry FAA approval as
alternate methods of compliance to allow operators the greatest
flexibility in performing the requirements of an AD.
One commenter states that the inspection thresholds should be based
on cycles since new on the issuance of GE CF6-80A SB No. 72-604,
Revision 2, dated July 2, 1992, rather than the effective date of the
AD to be consistent with their current inspection program. The FAA does
not concur. This recommendation might cause an undue burden to another
operator based on the anticipated publication date of this amendment.
The FAA has determined that the compliance end date of December 31,
1993, noted in compliance paragraph (a)(3) of the NPRM, is inconsistent
with the anticipated publication date of this amendment, and as such
may place undue burden on operators. The NPRM proposed a compliance
period of 60 days to accomplish the required actions based on the
anticipated publication date of the AD at the time the NPRM was
published. Therefore, the compliance end date in compliance paragraph
(a)(3) of this final rule has been revised to 90 days after date of
publication in the Federal Register. This time period is comprised of
the 30 day period after publication and prior to the effective date
plus 60 days.
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 change described
previously. The FAA has determined that this change will neither
increase the economic burden on any operator nor increase the scope of
the AD.
There are approximately 154 GE CF6-80A series engines of the
affected design in the worldwide fleet. The FAA estimates that 48
engines installed on aircraft of U.S. registry will be affected by this
AD, that it will take approximately 232 work hours per engine to
accomplish the required actions, and that the average labor rate is $55
per work hour. Required parts will cost approximately $172,800 per
engine. Based on these figures, and assuming all inspected disks
require replacement, the total cost impact of the AD on U.S. operators
is estimated to be $8,906,880.
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.
Adoption of the Amendment
Accordingly, pursuant to the authority delegated to me by the
Administrator, the Federal Aviation Administration amends 14 CFR part
39 of the Federal Aviation Regulations 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.
Sec. 39.13 [Amended]
2. Section 39.13 is amended by adding the following new
airworthiness directive:
94-07-04 General Electric Company: Amendment 39-8862. Docket 91-ANE-
45.
Applicability: General Electric Company (GE) CF6-80A series
turbofan engines installed on but not limited to, Boeing 767 series
and Airbus A310 series aircraft.
Compliance: Required as indicated, unless accomplished
previously.
To prevent an uncontained stage 1 high pressure turbine (HPT)
disk failure, which could result in an inflight engine shutdown,
rejected takeoff, or damage to the aircraft, accomplish the
following:
(a) Eddy current inspect (ECI) for cracks stage 1 HPT disks,
Part Numbers (P/N) 9234M67G12, 9234M67G13, 9234M67G14, 9234M67G15,
9234M67G16, 9234M67G22, 9234M67G24, 9367M45G01, 9367M45G02,
9367M45G03, and 9367M45G04, regardless of serial number; and stage 1
HPT disks, P/N 9362M58G02, with serial numbers listed in paragraph
1.A. of GE CF6-80A Service Bulletin (SB) No. 72-604, Revision 3,
dated April 8, 1993; in accordance with the accomplishment
instructions of GE CF6-80A SB No. 72-604, Revision 3, dated April 8,
1993, as follows:
(1) For disks that have accumulated less than 3,000 cycles since
new (CSN) on the effective date of this AD, ECI the rim bolt holes
at the next engine shop visit after accumulating 3,000 CSN, but not
to exceed 4,500 CSN.
(2) For disks that have accumulated 3,000 CSN or more, but less
than 4,000 CSN on the effective date of this AD, ECI the rim bolt
holes at the next engine shop visit, but not to exceed 4,500 CSN.
(3) For disks that have accumulated 4,000 CSN or more, but less
than 9,500 CSN on the effective date of this AD, ECI the rim bolt
holes at the next engine shop visit, or prior to July 20, 1994,
whichever occurs earlier.
(4) For disks that have accumulated 9,500 CSN or more on the
effective date of this AD, ECI the rim bolt holes at the next engine
shop visit.
(b) ECI stage 1 HPT disks, P/N 9362M58G02, with serial numbers
not listed in paragraph 1.A. of GE CF6-80A SB No. 72-604, Revision
3, dated April 8, 1993, in accordance with the accomplishment
instructions of GE CF6-80A SB No. 72-604, Revision 3, dated April 8,
1993, at the next exposure of the stage 1 HPT disk at the piece part
level.
(c) Remove from service disks found cracked, and replace with
serviceable parts. Inspect replacement disks in accordance with
paragraph (a) or (b) of this AD, if applicable.
(d) Disks referenced in paragraph (a) or (b) of this AD that
have been inspected in accordance with Commercial Engine Service
Memorandum No. 27, dated September 27, 1991, or any revision level
of GE CF6-80A SB No. 72-604, prior to the effective date of this AD,
and whose CSN at the time of inspection was 3,000 or more, meet the
inspection requirements of paragraph (a) and (b) of this AD.
(e) For the purpose of this AD, an engine shop visit is defined
as the induction of an engine into a shop for maintenance involving
the separation of any major flange.
(f) An alternative method of compliance or adjustment of the
initial 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.
(g) Special flight permits may be issued in accordance with FAR
21.197 and 21.199 to operate the aircraft to a location where the
requirements of this AD can be accomplished.
(h) The inspection, and replacement, if necessary, shall be done
in accordance with the following service bulletin:
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Document No. Pages Revision Date
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GE CF6-80A SB No. 72-604 1 3 Apr. 8, 1993.
2 2 July 2, 1992.
3 3 Apr. 8, 1993.
4-12 2 July 2, 1992.
Total Pages: 12.....
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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.
(i) This amendment becomes effective on May 23, 1994.
Issued in Burlington, Massachusetts, on March 23, 1994.
Marc Bouthillier,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 94-7785 Filed 4-20-94; 8:45 am]
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