[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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