[Federal Register Volume 62, Number 188 (Monday, September 29, 1997)]
[Rules and Regulations]
[Pages 50862-50865]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 97-25581]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 97-ANE-15; Amendment 39-10137; AD 97-19-17]
RIN 2120-AA64
Airworthiness Directives; General Electric Company CT58 Series
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 Company CT58 series turboshaft engines,
that requires removal from service of certain compressor rear shafts,
initial and repetitive inspections of specific critical rotating parts,
and replacement if found cracked, until those parts are removed from
service and replaced with improved design parts. This amendment is
prompted by a stage 2 turbine wheel
[[Page 50863]]
incident in 1993 which resulted in an increased awareness of small
features on critical rotating parts which could affect part life. The
actions specified by this AD are intended to prevent fatigue cracking
on specific critical rotating parts, which could result in failure of
the part, causing an uncontained engine failure and damage to the
aircraft.
DATES: Effective November 28, 1997.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of November 28, 1997.
ADDRESSES: The service information referenced in this AD may be
obtained from General Electric Aircraft Engines, Technical
Publications, 1000 Western Avenue, Lynn, MA 01910; telephone (781) 594-
5102, fax (781) 594-2717. 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: Diane Cook, Aerospace Engineer, Engine
Certification Office, FAA, Engine and Propeller Directorate, 12 New
England Executive Park, Burlington, MA 01803-5299; telephone (781) 238-
7133, 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 (GE) CT58
series turboshaft engines was published in the Federal Register on
April 3, 1997 (62 FR 15861). That action proposed to require removal
from service of certain compressor rear shafts, initial and repetitive
inspections of specific critical rotating parts, and replacement if
found cracked, until those parts are removed from service and replaced
with improved design parts.
Interested persons have been afforded an opportunity to participate
in the making of this amendment. No comments were received on the
proposal or the FAA's determination of the cost to the public.
Since publication of the Notice of Proposed Rulemaking (NPRM), GE
has issued Revision 2 to GE Aircraft Engines Service Bulletin (SB) No.
(CT58) 72-181, CEB-284, dated July 15, 1997, which adds serial numbers
(S/Ns) of certain affected Stage 1 and Stage 2 turbine wheels that
require inspections. Revision 1 to GE Aircraft Engines SB No. (CT58)
72-181, CEB-284, dated November 29, 1995, is no longer current and is
not an acceptable Alternative Method of Compliance (AMOC) for this AD.
In addition, GE has issued Revision 8 to GE Aircraft Engines SB No.
(CT58) A72-162, CEB-258, dated June 16, 1997, that makes editorial
changes to the SB. Revisions 5 through 7 of this SB are considered
acceptable AMOCs for this AD.
Also, the FAA has revised the economic analysis to better reflect
the lower number of affected engines, since not all Stage 1 and Stage 2
turbine wheels now require inspections, only those listed by S/Ns in GE
Aircraft Engines SB No. (CT58) 72-181, CEB-284, dated July 15, 1997.
After careful review of the available data, 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.
There are approximately 400 engines of the affected design in the
worldwide fleet. The FAA estimates that 126 engines installed on
aircraft of U.S. registry will be affected by this AD, that it will
take approximately zero additional work hours per engine to accomplish
the required actions. Required parts will cost approximately $2,730 per
engine, based on the estimated current part cost, as the manufacturer
will prorate the cost to the operator downward by a factor equal to the
quotient of the difference between the original life limit (4,000 hours
time in service) and the total cycles of life consumed at time of
removal, divided by the original life limit. Based on these figures,
the total cost impact of the AD on U.S. operators is estimated to be
$56,650.
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 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:
97-19-17 General Electric Company: Amendment 39-10137. Docket 97-
ANE-15.
Applicability: General Electric Company (GE) Models CT58-100-2,
-110-1/-2, -140-1/-2, and T58-GE-3/-5/-10/-100 turboshaft engines,
installed on but not limited to Boeing Vertol 107 series, and
Sikorsky S61 and S62 series aircraft.
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 (f) 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 fatigue cracking on specific critical rotating parts,
which could result in failure of the part, causing an uncontained
engine failure and damage to the aircraft, accomplish the following:
(a) Determine hours time in service (TIS) and cycles in service
(CIS) in accordance with the improved methodology described in GE
Aircraft Engines Service Bulletin (SB) No.
[[Page 50864]]
(CT58) A72-162, CEB-258, Revision 8, dated June 16, 1997.
(b) For engines that have engaged in repeated heavy lift (RHL)
operations, as defined in paragraph (e) of this
AD, accomplish the following:
(1) For compressor rear shafts, Part Numbers (P/N's) 4000T29P01/
P03, 5016T95P01/P04, and 5013T86P03, accomplish the following:
(i) For compressor rear shafts, with either 2,975 or more hours
TIS, or 9,550 or more CIS, on the effective date of this AD, remove
compressor rear shafts and replace with a serviceable compressor
rear shaft at the next light overhaul or next exposure of compressor
rear shafts after the effective date of this AD, whichever occurs
first.
(ii) For all other compressor rear shafts, remove compressor
rear shafts and replace with a serviceable compressor rear shaft,
prior to accumulating 3,000 hours TIS, or 9,600 CIS, whichever
occurs first.
(iii) For all compressor rear shafts, remove from service and
replace with a serviceable, redesigned compressor rear shaft, P/N
5016T95P06, not later than December 31, 1997.
(2) Initially inspect the ten rotating parts specified in
paragraph (d) of this AD for cracks at the times specified in sub-
paragraphs (i) and (ii) of this paragraph, and, thereafter, inspect
at each light overhaul or major overhaul until the parts are retired
from service. Perform the inspections in accordance with the
procedures described in GE Aircraft Engines SB No. (CT58) 72-181,
CEB-284, Revision 2, dated July 15, 1997. Prior to further flight,
replace parts found cracked during these inspections with
serviceable parts.
(i) For parts with greater than the baseline time in service
(TIS) on the effective date of this AD, inspect at the earliest
occurrence of the following after the effective date of this AD: the
next light overhaul, the next major overhaul, or the next exposure
of the affected parts.
(ii) For parts with less than or equal to the baseline TIS on
the effective date of this AD, inspect within 1,000 hours TIS from
the listed baseline TIS.
(c) For engines that have never engaged in RHL operations,
accomplish the following:
(1) For compressor rear shafts, P/N's 4000T29P01/P03,
5016T95P01/P04, and 5013T86P03, remove compressor rear shafts and
replace with a serviceable compressor rear shaft, prior to
accumulating 9,600 CIS, or 9,000 hours TIS, whichever occurs first.
Prior to December 31, 1999, replace compressor rear shafts with a
serviceable, redesigned compressor rear shaft, P/N 5016T95P06.
(2) Initially inspect the ten rotating parts specified in
paragraph (d) of this AD for cracks at the times specified in sub-
paragraphs (i) and (ii) of this paragraph, and, thereafter, at each
light overhaul or major overhaul until the parts are retired from
service. Perform the inspections in accordance with the procedures
described in GE Aircraft Engines SB No. (CT58) 72-181, CEB-284,
Revision 2, dated July 15, 1997. Prior to further flight, replace
parts found cracked during these inspections with serviceable parts.
(i) For parts with greater than the baseline TIS on the
effective date of this AD, inspect at the earliest occurrence of the
following after the effective date of this AD: the next light
overhaul, the next major overhaul, or the next exposure.
(ii) For parts with less than or equal to the baseline TIS on
the effective date of this AD, inspect within 2,000 hours TIS from
the listed baseline hours.
(d) For the purpose of performing the inspections required by
paragraphs (b)(2) and (c)(2) of this AD, the following baseline TIS
are established:
(1) For compressor rotor spool assemblies, P/N's 6010T57G04 and
6010T57G08, whether or not used in RHL operations, baseline is 2,000
hours TIS.
(2) For turbine front shafts, P/N's 5003T35P01 and 573D358P002,
whether or not utilized in RHL operation, baseline is 1,000 hours
TIS.
(3) For turbine coupling shafts, P/N's 4001T26P01 and
278D987P002, if utilized in RHL operation, baseline is 1,000 hours
TIS; if never utilized in RHL operations, baseline is 2,000 hours
TIS.
(4) For turbine rear shafts, P/N's 4005T29P01 and 37D400244P101,
whether or not utilized in RHL operation, baseline is 2,000 hours
TIS.
(5) For Stage 1 front cooling plates, P/N's 37C300055P101,
whether or not utilized in RHL operation, baseline is 1,000 hours
TIS.
(6) For Stage 1 aft cooling plates, P/N's 3002T25P01 and
645C334P002, whether or not utilized in RHL operation, baseline is
1,000 hours TIS.
(7) For Stage 2 front cooling plates, P/N's 3000T88P02 and
645C332P002, whether or not utilized in RHL operation, baseline is
1,000 hours TIS.
(8) For Stage 2 aft cooling plates, P/N's 3002T27P01 and
645C336P002, whether or not utilized in RHL operation, baseline is
1,000 hours TIS.
(9) For Stage 1 turbine wheels, P/N 4002T17P02 TF3, listed by
Serial Numbers (S/Ns) in paragraph 1.A. (3) of GE Aircraft Engines
SB No. (CT58) 72-181, CEB-284, Revision 2, dated July 15, 1997, if
utilized in RHL operation, baseline is 1,000 hours TIS; if never
utilized in RHL operation, baseline is 2,000 hours TIS.
(10) For Stage 2 turbine wheels, P/N 4002T96P02 TF3, listed by
S/Ns in paragraph 1.A. (3) of GE Aircraft Engines SB No. (CT58) 72-
181, CEB-284, Revision 2, dated July 15, 1997, if utilized in RHL
operation, baseline is 1,000 hours TIS; if never utilized in RHL
operation, baseline is 2,000 hours TIS.
(e) For the purpose of this AD, the following definitions apply:
(1) RHL operation is defined as performing more than 10 lift-
carry-drop cycles per hour TIS without landing, or more than 10
takeoffs and landings per hour TIS.
(2) Light overhaul is defined as scheduled engine maintenance
that allows the engine to continue in service until scheduled major
overhaul time is reached.
(3) Major overhaul is defined as scheduled engine maintenance
including complete engine inspections and tests with repair or
replacement of parts or components as necessary.
(f) 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 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.
(g) 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 inspection requirements of this AD can be accomplished.
(h) The actions required by this AD shall be done in accordance
with the following GE Aircraft Engines SBs:
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Document number Pages Revision Date
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(CT58) 72-181, CEB-284......................... 1-22 2 July 15, 1997.
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Total pages.............................. 22
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(CT58) A72-162, CEB-258........................ 1 7 April 25, 1997.
2,3 8 June 16, 1997.
4,5 5 May 12, 1994.
6 7 April 25, 1997.
7,8 5 May 12, 1994.
9-11, 7 April 25, 1997.
12-16 5 May 12, 1994.
17 7 April 25, 1997.
18-20 5 May 12, 1994.
[[Page 50865]]
21 8 June 16, 1997.
22-24 5 May 12, 1994.
25, 26 7 April 25, 1997.
27 5 May 12, 1994.
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Total pages.............................. 27
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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, Technical Publications, 1000 Western Avenue, Lynn, MA
01910; telephone (781) 594-5102, fax (781) 594-2717. 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 November 28, 1997.
Issued in Burlington, Massachusetts, on September 11, 1997.
Mark C. Fulmer,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 97-25581 Filed 9-26-97; 8:45 am]
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