[Federal Register Volume 60, Number 90 (Wednesday, May 10, 1995)]
[Rules and Regulations]
[Pages 24762-24765]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11353]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 94-ANE-45; Amendment 39-9221; AD 95-10-04]
Airworthiness Directives; AlliedSignal Inc. (Formerly Textron
Lycoming and Avco Lycoming) Model T5313B and T5317 Series Turboshaft
Engines
AGENCY: Federal Aviation Administration, DOT.
ACTION: Final rule; request for comments.
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SUMMARY: This amendment supersedes an existing airworthiness directive
(AD), applicable to AlliedSignal Inc. (formerly Textron Lycoming and
Avco Lycoming) Model T5313B and T5317 series turboshaft engines, that
currently requires initial and repetitive dye penetrant inspections of
the centrifugal compressor impeller for cracks, and if necessary,
removal from service. This amendment requires the use of a new, more
conservative minor cycle counting factors table, introduces a method
for prorating past centrifugal compressor impeller usage based on the
new cycle counting factors, provides an enhanced centrifugal compressor
impeller inspection procedure, and eliminates flyback criteria based on
crack size. For those centrifugal compressor impellers that exceed
their published life limit, this amendment implements a schedule for
safe removal of time-expired parts. This amendment is prompted by a
report of an uncontained centrifugal compressor impeller failure and
subsequent rotorcraft accident. The actions specified by this AD are
intended to prevent centrifugal compressor impeller failure, which can
result in an uncontained engine failure, inflight engine shutdown, or
damage to the rotorcraft.
DATES: Effective May 25, 1995.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of May 25, 1995.
Comments for inclusion in the Rules Docket must be received on or
before July 10, 1995.
ADDRESSES: Submit comments in triplicate to the Federal Aviation
Administration (FAA), New England Region, Office of the Assistant Chief
Counsel, Attention: Rules Docket No. 94-ANE-45, 12 New England
Executive Park, Burlington, MA 01803-5299.
The service information referenced in this AD may be obtained from
AlliedSignal Inc., 550 Main St., Stratford, CT 06497; telephone (203)
385-5452. This information may be examined at the FAA, New England
Region, Office of the Assistant Chief Counsel, Burlington, MA; or at
the Office of the Federal Register, 800 North Capitol Street, NW.,
suite 700, Washington, DC.
FOR FURTHER INFORMATION CONTACT: Daniel Kerman, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7130, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: On April 14, 1986, the Federal Aviation
Administration (FAA) issued airworthiness directive (AD) 86-09-05,
[[Page 24763]] Amendment 39-5293 (51 FR 16506, May 5, 1986), applicable
to Avco Lycoming Models T5313B and T5317A turboshaft engines, to
require initial and repetitive dye penetrant inspections of the
centrifugal compressor impeller for cracks, and if necessary, removal
from service. That action was prompted by reports of two centrifugal
compressor impellers found cracked at the pressure equalization holes,
and one impeller that had ruptured, causing an uncontained engine
failure. That condition, if not corrected, could result in centrifugal
compressor impeller failure, which can result in an uncontained engine
failure, inflight engine shutdown, or damage to the rotorcraft.
Since the issuance of that AD, the FAA has received a report of an
accident of a rotorcraft performing repetitive heavy lift (RHL)
operations that was caused by an uncontained failure of a centrifugal
compressor impeller installed on an AlliedSignal Inc. Model T5317A
engine. On October 28, 1994, AlliedSignal Inc. purchased the turbine
engine product line from Textron Lycoming. The centrifugal compressor
impeller failure was caused by a low cycle fatigue (LCF) crack that
initiated and propagated to failure in one of two pressure equalization
holes. Following this accident AlliedSignal Inc. has performed
engineering analysis that has determined that the existing impeller
specific cyclic counting factors were insufficient to account for RHL
operations. Updated operator mission profiles and analysis has shown
that minor cycle LCF damage associated with RHL operation is greater
than previously calculated. Previous inspection instructions required
by AD 86-09-05 could result in incomplete inspection of the pressure
equalization holes. Experience has shown that cracks in these holes may
initiate at the interior of the centrifugal compressor impeller.
The FAA has reviewed and approved the technical contents of Textron
Lycoming Service Bulletin (SB) No. T5313B/17-0020, Revision 4, dated
July 5, 1994, that revises the impeller minor cycle counting factors
for cyclic computation, and provides a method for prorating past
centrifugal compressor impeller usage based on the new cycle counting
factors. Also, for those centrifugal compressor impellers that exceed
their published life limit, this SB implements a schedule for safe
removal of time-expired parts. In addition, the FAA has reviewed and
approved the technical contents of Textron Lycoming SB No. T5313B/17
0052, Revision 2, dated December 16, 1993, that describes enhanced
inspection procedures for greater inspection reliability, and removes
flyback criteria based on crack size.
Since an unsafe condition has been identified that is likely to
exist or develop on other engines of this same type design, this AD
supersedes AD 86-09-05 to require the following actions: utilization of
a new, more conservative minor cycle counting factors table,
introduction of a method for prorating past centrifugal compressor
impeller usage based on the new cycle counting factors, an enhanced
centrifugal compressor impeller inspection procedure, and elimination
of flyback criteria based on crack size. For those centrifugal
compressor impellers that exceed their published life limit, this
amendment implements a schedule for safe removal of time-expired parts.
The actions are required to be accomplished in accordance with the
service bulletins described previously.
Since a situation exists that requires the immediate adoption of
this regulation, it is found that notice and opportunity for prior
public comment hereon are impracticable, and that good cause exists for
making this amendment effective in less than 30 days.
Comments Invited
Although this action is in the form of a final rule that involves
requirements affecting flight safety and, thus, was not preceded by
notice and an opportunity for public comment, comments are invited on
this rule. Interested persons are invited to comment on this rule by
submitting such written data, views, or arguments as they may desire.
Communications should identify the Rules Docket number and be submitted
in triplicate to the address specified under the caption ADDRESSES. All
communications received on or before the closing date for comments will
be considered, and this rule may be amended in light of the comments
received. Factual information that supports the commenter's ideas and
suggestions is extremely helpful in evaluating the effectiveness of the
AD action and determining whether additional rulemaking action would be
needed.
Comments are specifically invited on the overall regulatory,
economic, environmental, and energy aspects of the rule that might
suggest a need to modify the rule. All comments submitted will be
available, both before and after the closing date for comments, in the
Rules Docket for examination by interested persons. A report that
summarizes each FAA-public contact concerned with the substance of this
AD will be filed in the Rules Docket.
Commenters wishing the FAA to acknowledge receipt of their comments
submitted in response to this notice must submit a self-addressed,
stamped postcard on which the following statement is made: ``Comments
to Docket Number 94-ANE-45.'' The postcard will be date stamped and
returned to the commenter.
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.
The FAA has determined that this regulation is an emergency
regulation that must be issued immediately to correct an unsafe
condition in aircraft, and is not a ``significant regulatory action''
under Executive Order 12866. It has been determined further that this
action involves an emergency regulation under DOT Regulatory Policies
and Procedures (44 FR 11034, February 26, 1979). If it is determined
that this emergency regulation otherwise would be significant under DOT
Regulatory Policies and Procedures, a final regulatory evaluation will
be prepared and placed in the Rules Docket. A copy of it, if filed, 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. 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 removing Amendment 39-5293 (51 FR
16506, May 5, 1986), and by adding a new airworthiness directive,
[[Page 24764]] Amendment 39-9221, to read as follows:
95-10-04 AlliedSignal Inc.: Amendment 39-9221. Docket 94-ANE-45.
Supersedes AD 86-09-05, Amendment 39-5293.
Applicability: AlliedSignal Inc. (formerly Textron Lycoming and
Avco Lycoming) Model T5313B and T5317 series turboshaft engines,
installed on but not limited to Bell 205 series rotorcraft.
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 centrifugal compressor impeller failure, which can
result in an uncontained engine failure, inflight engine shutdown,
or damage to the rotorcraft, accomplish the following:
(a) Within seven days after the effective date of this
airworthiness directive (AD), conduct a revised centrifugal
compressor impeller operating cycle count (prorate) in accordance
with paragraph 2.E. of Textron Lycoming Service Bulletin (SB) No.
T5313B/17-0020, Revision 4, dated July 5, 1994.
(b) Following the revised operating cycle count required by
paragraph (a) of this AD, remove from service centrifugal compressor
impellers installed on rotorcraft that exceed their life limit on
the effective date of this AD, within 50 hours time in service
(TIS), or 25 operating cycles, whichever occurs first, and replace
with a serviceable part that does not exceed the life limit.
(c) Following the revised operating cycle count required by
paragraph (a) of this AD, reinstallation of uninstalled centrifugal
compressor impellers that exceed their life limit is prohibited.
(d) Inspect centrifugal compressor impellers, Part Numbers (P/N)
1-100-078-07 and 1-100-078-08, in accordance with the Accomplishment
Instructions of Textron Lycoming SB No. T5313B/17-0052, Revision 2,
dated December 16, 1993, as follows:
(1) For those centrifugal compressor impellers installed on
AlliedSignal Inc. Model T5313B engines, accomplish the following:
(i) For centrifugal compressor impellers with equal to or
greater than 4,600 cycles in service (CIS) on the effective date of
this AD, initially inspect within 200 CIS after the effective date
of this AD.
(ii) For those centrifugal compressor impellers with less than
4,600 CIS on the effective date of this AD, initially inspect no
later than 4,800 CIS.
(2) For those centrifugal compressor impellers installed on
AlliedSignal Inc. T5317 series engines, accomplish the following:
(i) For those centrifugal compressor impellers with equal to or
greater than 3,500 CIS on the effective date of this AD, initially
inspect within 200 CIS after the effective date of this AD.
(ii) For those centrifugal compressor impellers with less than
3,500 CIS on the effective date of this AD, initially inspect no
later than 3,700 CIS.
(3) Centrifugal compressor impellers found cracked in accordance
with the Accomplishment Instructions of Textron Lycoming SB No.
T5313B/17-0052, Revision 2, dated December 16, 1993, must be removed
from service and replaced with a serviceable part that does not
exceed the life limit.
(4) If no cracks are detected, perform repetitive inspections of
the centrifugal compressor impellers at intervals not to exceed 500
CIS since last inspection in accordance with the Accomplishment
Instructions of Textron Lycoming SB No. T5313B/17-0052, Revision 2,
dated December 16, 1993.
(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
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.
(g) The actions required by this AD shall be done in accordance
with the following Textron Lycoming service bulletins:
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Document No. Pages Revision Date
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No. T5313B/17-0052....................................... 1-8 2 December 16, 1993.
Total pages: 8.
No. T5313B/17-0020....................................... 1-14 4 July 5, 1994.
Total pages: 14.
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[[Page 24765]] 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 AlliedSignal
Inc., 550 Main St., Stratford, CT 06497; telephone (203) 385-5452.
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.
(h) This amendment becomes effective on May 25, 1995.
Issued in Burlington, Massachusetts, on May 1, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft
Certification Service.
[FR Doc. 95-11353 Filed 5-9-95; 8:45 am]
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