[Federal Register Volume 61, Number 36 (Thursday, February 22, 1996)]
[Rules and Regulations]
[Pages 6766-6768]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 96-2589]
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DEPARTMENT OF TRANSPORTATION
Federal Aviation Administration
14 CFR Part 39
[Docket No. 95-ANE-08; Amendment 39-9459; AD 95-26-01]
Airworthiness Directives; AlliedSignal, Inc. (formerly Textron
Lycoming) Models LTS101-650B1, -750B1, -650C, and -750C 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 AlliedSignal, Inc. (formerly Textron Lycoming) Models
LTS101-650B1, -750B1, -650C, and -750C turboshaft engines, that
requires installation of an improved power turbine (PT) rotor and
electronic PT rotor overspeed controller as a terminating action to the
currently required inspections of AD 88-14-01. This amendment is
prompted by reports of additional bearing failures since publication of
AD 88-14-01, including one additional uncontained PT disk failure. The
actions specified by this AD are intended to prevent PT overspeed and
uncontained engine failure.
DATES: Effective April 22, 1996.
The incorporation by reference of certain publications listed in
the regulations is approved by the Director of the Federal Register as
of April 22, 1996.
ADDRESSES: The service information referenced in this AD may be
obtained from AlliedSignal Inc., 550 Main Street, Stratford, CT 06497.
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: Eugene Triozzi, Aerospace Engineer,
Engine Certification Office, FAA, Engine and Propeller Directorate, 12
New England Executive Park, Burlington, MA 01803-5299; telephone (617)
238-7148, fax (617) 238-7199.
SUPPLEMENTARY INFORMATION: On May 26, 1988, the Federal Aviation
Administration (FAA) issued airworthiness directive (AD) 88-14-01,
Amendment 39-5952 (53 FR 25317, July 6, 1988), to require initial and
repetitive inspections of the engine lubrication and bearing systems on
AlliedSignal, Inc. (formerly Textron Lycoming) LTS101 series turboshaft
engines. That action was prompted by reports of four uncontained power
turbine (PT) disk failures. Subsequent investigation revealed that the
PT disk failures were caused by bearing failures resulting in PT shaft
disengagement from the gear train drive, unloading the PT and causing
rotor overspeed. Two other PT disk failures involved No. 4 bearing
failure, followed by power pinion gear teeth failure, thereby unloading
the PT and causing PT rotor overspeed. This condition, if not
corrected, could result in PT overspeed and uncontained engine failure.
Since the issuance of that AD, the FAA has received reports of
additional bearing failures with resultant loss of PT rotor location,
including one additional uncontained PT disk failure. In order to
minimize the possibility of an uncontained engine failure, the
manufacturer has developed an improved PT rotor with retention
capability and an improved electronic PT rotor overspeed controller.
These improvements are only available for AlliedSignal, Inc. Models
LTS101-650B1, -750B1, -650C, and -750C turboshaft engines, installed on
Bell Helicopter Textron 222 series and Messerschmitt-Bolkow-Blohm (MBB)
BK117 series helicopters.
A proposal to amend part 39 of the Federal Aviation Regulations (14
CFR part 39) to include an AD that is applicable to AlliedSignal, Inc.
(formerly Textron Lycoming) Models LTS101-650B1, -750B1, -650C, and -
750C turboshaft engines was published in the Federal Register on May
19, 1995 (60 FR 26846). That action proposed to require installation of
an improved PT rotor with retention capability and an electronic PT
rotor overspeed controller at the next shop visit when the PT rotor is
removed after the effective date of this AD, but prior to December 31,
1997, as a terminating action to the currently required inspections of
AD 88-14-01.
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 states that the requirement to incorporate an
electronic PT overspeed controller should be deleted from the AD, as
the additional economic impact is not justified from the basis of
increased safety, or the basis of reliability in adverse operating
conditions. The FAA does not concur. The FAA has determined that the
electronic PT overspeed controller will increase flight safety by
providing overspeed protection in the event of a No. 4 bearing failure.
As stated in the NPRM, the current PT rotor overspeed controller, in
two cases of No. 4 bearing failure, has allowed PT rotor overspeed and
uncontained PT disk failures. The FAA has also determined that the
electronic PT overspeed protection system provides an acceptable level
of reliability in adverse environmental operating conditions consistent
with that required for engine digital electronic controls.
One commenter states that the pneumatic portion of the PT retention
system should be enabled in lieu of
[[Page 6767]]
installation of the electronic PT overspeed controller, as this would
be a more cost effective improvement. The FAA does not concur. The
pneumatic portion of the PT retention system would not provide
overspeed protection in the event of a No. 4 bearing failure. Available
data shows that the pneumatic portion of the PT retention system
provides automatic shutdown only in the event of loss of PT rotor axial
location.
One commenter states that the requirements of AD 88-14-01 should be
continued with no terminating actions, thereby continuing preventive
maintenance benefits. The FAA does not concur. The FAA has approved
incorporation of applicable ongoing maintenance requirements currently
in AD 88-14-01 into the applicable AlliedSignal, Inc. LTS101 engine
maintenance manual requirements. The FAA considers that incorporation
of these requirements into the maintenance manuals will provide
desirable preventive maintenance actions for the AlliedSignal, Inc.
LTS101 engine, while the design modifications proposed would alleviate
the additional record-keeping burden imposed by AD 88-14-01.
One commenter states that the compliance timetable for
incorporation of electronic PT rotor overspeed controller should be
revised to allow installation at a scheduled aircraft inspection rather
than at the next PT rotor removal. This change is requested because
incorporation of electronic PT rotor overspeed controller at the next
PT rotor removal may not be logistically supportable due to the
increased rate of PT rotor removals resulting from another field
management plan. The FAA concurs. Adoption of the revised timetable
will minimize the possible logistic impact of the original compliance
timetable while still providing the equivalent level of safety proposed
by the NPRM.
One commenter states that the proposed AD should apply only for
engines that do not incorporate the insertable blade PT rotor. The FAA
concurs in part. The PT rotor with retention capability, to be required
by the proposed rule, is the same as the insertable blade PT rotor.
Therefore, the PT rotor installation required by the proposed rule
would be previously accomplished for engines with the insertable blade
PT rotor. However, as addressed in a previous comment, the FAA has
determined that installation of the electronic PT overspeed controller
is required for all engines regardless of the P/N PT rotor installed,
in order to provide overspeed protection in the event of a No. 4
bearing failure.
One commenter states that the economic impact of the proposed rule
should be revised to reflect installation of aircraft electronics
necessary for operation of the electronic overspeed system. The FAA
concurs, and has adjusted the economic impact to reflect the associated
increase in the cost impact.
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 changes described
previously. The FAA has determined that these changes will not increase
the scope of the AD.
There are approximately 950 engines of the affected design in the
worldwide fleet. The FAA estimates that 95 engines installed on
aircraft of U.S. registry will be affected by the requirement to
install the PT rotor with improved retention, that it will take
approximately 10 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 $44,400 per engine. Based on these
figures, the cost impact of the AD on U.S. operators is estimated to be
$4,275,000 for installation of the PT rotor with improved retention.
In addition, the FAA estimates that 576 engines installed on
aircraft of U.S. registry will be affected by the requirement to
install the electronic PT rotor overspeed controller, that it will take
approximately 3 work hours per engine to accomplish the required
action, and that the average labor rate is $60 per work hour. Required
parts cost for the electronic PT rotor overspeed controller
installation is $5,825. Based on these figures, the cost impact of
installing the electronic PT rotor overspeed controller would be
$3,458,880.
There are approximately 288 aircraft of U.S. registry that would be
affected by the requirement to install aircraft electronics necessary
for the functioning of the electronic PT rotor overspeed controller. It
would take approximately 80 work hours per aircraft to accomplish the
proposed actions, and the average labor rate is $60 per work hour.
Required parts for the aircraft installation would be approximately
$4,531. Based on these figures, the cost impact of installing the
aircraft electronics for the electronic PT rotor overspeed controller
would be $2,287,328. Therefore, the revised total cost impact of all
the actions of the proposed AD on U.S. operators is estimated to be
$10,421,208.
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:
95-26-01 AlliedSignal, Inc.: Amendment 39-9459 Docket 95-ANE-08.
Applicability: AlliedSignal, Inc. (formerly Textron Lycoming)
Model LTS101-650B1, -750B1, -650C, and -750C turboshaft engines
installed on Bell Helicopter Textron 222 series and Messerschmitt-
Bolkow-Blohm (MBB) BK117 series helicopters.
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
[[Page 6768]]
owner/operator must use the authority provided in paragraph (d) 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 power turbine (PT) overspeed and uncontained engine
failure, accomplish the following:
(a) Install the improved PT rotor with retention capability at
the next shop visit when the PT rotor is removed after the effective
date of this AD, but prior to December 31, 1997, in accordance with
the following Textron Lycoming Service Bulletins (SB):
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Engine model SB No. Rev. Date
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LTS101-650B1................... LTS101B-72-50-0122 4 June 17, 1991.
LTS101-750B1 or -650B1......... LTS101B-72-50-0116 6 August 14, 1992.
LTS101-650C and -750C Series... LTS101C-72-50-0119 2 June 17, 1991.
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(b) Install the improved electronic PT rotor overspeed
controller concurrently with the PT rotor installation required by
paragraph (a) of this AD, or at the next airframe 600 hour
inspection point after the effective date of this AD, whichever
occurs later, in accordance with the following Textron Lycoming SB:
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Engine model SB No. Rev. Date
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LTS101-650B1................... LTS101B-73-10-0127 2 August 14, 1992.
LTS101-750B1................... LTS101B-73-10-0127 2 August 14, 1992.
LTS101-650C and -750C Series... LTS101C-73-10-0129 3 August 14, 1992.
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(c) Installation of the improved PT rotor with retention
capability and the improved electronic PT rotor overspeed controller
in accordance with paragraphs (a) and (b) of this AD constitutes
terminating action to the inspection requirements of AD 88-14-01.
(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 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
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.
(f) The actions required by this AD shall be done in accordance
with the following service bulletins:
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Document No. Pages Revision Date
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LTS101B-72-50-0122......................... 1-11 4 June 17, 1991.
Total pages:......................... 11
LTS101B-72-50-0116......................... 1-10 6 August 14, 1992.
Total pages:......................... 10
LTS101C-72-50-0119......................... 1-11 2 June 17, 1991.
Total pages:......................... 11
LTS101B-73-10-0127......................... 1-13 2 August 14, 1992.
Total pages:......................... 13
LTS101C-73-10-0129......................... 1-14 3 August 14, 1992.
Total pages:......................... 14
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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 AlliedSignal Inc., 550 Main
Street, Stratford, CT 06497. 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 April 22, 1996.
Issued in Burlington, Massachusetts, on January 24, 1996.
Jay J. Pardee,
Manager, Engine and Propeller Directorate, Aircraft Certification
Service.
[FR Doc. 96-2589 Filed 2-21-96; 8:45 am]
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