[Federal Register Volume 59, Number 1 (Monday, January 3, 1994)]
[Unknown Section]
[Page 0]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 93-31908]
Federal Register / Vol. 59, No. 1 / Monday, January 3, 1994 /
[[Page Unknown]]
[Federal Register: January 3, 1994]
VOL. 59, NO. 1
Monday, January 3, 1994
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 92-ANE-08; Amendment 39-8781; AD 93-25-17]
Airworthiness Directives; General Electric CT7 Series Turboprop
and Turboshaft 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 (GE) CT7 series turboprop and turboshaft
engines. This proposal would require the removal from service of
certain gas generator turbine (GGT) rotor assembly parts that were
plasma-sprayed during manufacture. This amendment is prompted by
material testing that indicates that the plasma-spray process reduces
the low cycle fatigue (LCF) capability of the material. The actions
specified by this AD are intended to prevent fatigue cracks that can
result in uncontained engine failure.
DATES: Effective February 2, 1994.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register, as
of February 2, 1994.
ADDRESSES: The service information referenced in this AD may be
obtained from General Electric Aircraft Engines, 1000 Western Avenue,
Lynn, Massachusetts 01910. This information may be examined at the FAA,
New England Region, Office of the Assistant Chief Counsel, Attn: Rules
Docket No. 92-ANE-08, 12 New England Executive Park, Burlington,
Massachusetts 01803-5299; or at the Office of the Federal Register, 800
North Capitol Street, NW., suite 700, Washington, DC 20001.
FOR FURTHER INFORMATION CONTACT: Barbara G. Caufield, Aerospace
Engineer, Engine Certification Branch, ANE-141, Engine Certification
Office, FAA, New England Region, Engine and Propeller Directorate,
Aircraft Certification Service, 12 New England Executive Park,
Burlington, Massachusetts 01803-5299; telephone (617) 238-7146; 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 CT7 series turboprop and turboshaft
engines was published in the Federal Register on November 13, 1992 (57
FR 53862). That action proposed to require the removal from service of
certain gas generator turbine (GGT) rotor assembly parts that were
plasma-sprayed during manufacture, and replacement with serviceable
parts. The actions would be required to be accomplished in accordance
with GE CT7 Turboprop Service Bulletin (SB) A72-252, dated August 31,
1990; and GE CT7 Turboshaft SB A72-17 and SB A72-18, both dated
September 10, 1990.
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 observes that the economic analysis in the proposed
AD is based on 23 engines being affected by the AD, when, in fact,
there are only 11 engines containing a combination of 23 parts. The FAA
concurs. The wording of the economic analysis for the final rule has
been changed 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.
The FAA estimates that 11 engines (containing 23 affected parts)
installed on aircraft of U.S. registry will be affected by this AD,
that it will take approximately 7 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 $8,255 per engine. Based
on these figures, the total cost impact of the AD on U.S. operators is
estimated to be $95,040. The manufacturer has advised the FAA that a
pro-rata credit allowance will be granted for labor and parts required
to accomplish these removals and replacements at a GE authorized
service or overhaul facility. Based on this information, the FAA has
determined that the total cost impact of the AD on U.S. operators would
be approximately $5,940 ($540 per engine).
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:
93-25-17. General Electric: Amendment 39-8781. Docket No. 93-ANE-08.
Applicability: General Electric (GE) Models CT7-5A2, -7A, and -
9C Turboprop Engines; and Models CT7-2A, and -6 Turboshaft Engines,
incorporating gas generator turbine (GGT) disks and cooling plates,
as listed by Part Number (P/N) and Serial Number (S/N) in GE CT7
Turboprop Service Bulletin (SB) A72-252, dated August 31, 1990; GE
CT7 Turobshaft SB A72-17, and GE CT7 Turboshaft SB A72-18, both
dated September 10, 1990, installed on, but not limited to, Saab
340A, Casa CN235-10, Bell 214ST, and European Helicopter Industries
EH101.
Compliance: Required as indicated, unless accomplished
previously.
To prevent fatigue cracks that can result in uncontained engine
failure, accomplish the following:
(a) Remove from service the affected GE Model(s) CT7-5A2, -7A,
and -9C engines GGT rotor stage 1 and 2 disks, and stage 2 forward
and aft cooling plates, prior to exceeding the ``Max total allowable
cycles''; as listed in GE CT7 Turboprop SB A72-252, dated August 31,
1990, and replace with serviceable parts.
(b) Remove from service the affected GE Model(s) CT7-6 engine
GGT rotor stage 1 disk and stage 2 forward cooling plate prior to
exceeding the ``Max total allowable cycles''; as listed in GE CT7
Turboprop SB A72-17, dated September 10, 1990, and replace with
serviceable parts.
(c) Remove from service the affected GE Model(s) CT7-2A engine
GGT rotor stage 2 disk and stage 2 forward cooling plate prior to
exceeding the ``Max total allowable cycles''; as listed in GE CT7
Turboshaft SB A72-8, dated September 10, 1990, and replace with
serviceable parts.
(d) 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.
(e) Special flight permits may be issued, in accordance with FAR
21.197 and 21.199, to operate the airplane to a location where the
requirements of this AD can be accomplished.
(f) The removals and replacements of the affected rotor stage
disks and cooling plates shall be done in accordance with the
following service bulletins:
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Document No. Page No. Issue Date
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GE CT7 Turboprop 1-13............ Original........ Aug 31, 1990
SB A72-252.
Total pages: 13
GE CT7 Turboshaft 1-4............. Original........ Sep 10, 1990
SB A72-17.
Total pages: 4
GE CT7 Turboshaft 1-4............. Original........ Sep 10, 1990
SB A72-18.
Total pages: 4
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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, 1000 Western Avenue, Lynn, Massachusetts 01910. Copies may
be inspected at the FAA, New England Region, Office of the Assistant
Chief Counsel, Attn: Rules Docket No. 92-ANE-08, 12 New England
Executive Park, Burlington, Massachusetts; or at the Office of the
Federal Register, 800 North Capitol Street NW., suite 700,
Washington, DC.
(g) This amendment becomes effective on February 2, 1994.
Issued in Burlington, Massachusetts, on December 21, 1993.
Jay J. Pardee,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 93-31908 Filed 12-30-93; 8:45 am]
BILLING CODE 4910-13-P
