[Federal Register Volume 60, Number 83 (Monday, May 1, 1995)]
[Proposed Rules]
[Pages 21053-21054]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-10594]



 ========================================================================
 Proposed Rules
                                                 Federal Register
 ________________________________________________________________________
 
 This section of the FEDERAL REGISTER contains notices to the public of 
 the proposed issuance of rules and regulations. The purpose of these 
 notices is to give interested persons an opportunity to participate in 
 the rule making prior to the adoption of the final rules.
 
 ========================================================================
 

  Federal Register / Vol. 60, No. 83 / Monday, May 1, 1995 / Proposed 
Rules  
[[Page 21053]]

DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 95-ANE-21]


Airworthiness Directives; AlliedSignal Engines LTS101 Series 
Turboshaft Engines Installed on Eurocopter France Model AS-350D and SA-
366G1 Helicopters

AGENCY: Federal Aviation Administration, DOT.

ACTION: Notice of proposed rulemaking (NPRM).

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SUMMARY: This document proposes the adoption of a new airworthiness 
directive (AD), applicable to AlliedSignal Engines (formerly Textron 
Lycoming) LTS101 series turboshaft engines installed on Eurocopter 
France (formerly Aerospatiale) Model AS-350D and SA-366G1 helicopters. 
This proposal would require incorporation of design modifications to 
the power turbine (PT) rotor. This proposal is prompted by reports of 
PT disk failures after No. 3 bearing failures. The actions specified by 
the proposed AD are intended to prevent an uncontained engine failure 
due to a PT disk failure.

DATES: Comments must be received by June 30, 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. 95-ANE-21, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8:00 a.m. and 4:30 p.m., Monday through Friday, 
except Federal holidays.
    The service information referenced in the proposed rule may be 
obtained from AlliedSignal Engines, 550 Main Street, Stratford, CT 
06497. This information may be examined at the FAA, New England Region, 
Office of the Assistant Chief Counsel, 12 New England Executive Park, 
Burlington, MA.

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:

Comments Invited

    Interested persons are invited to participate in the making of the 
proposed 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 above. All 
communications received on or before the closing date for comments, 
specified above, will be considered before taking action on the 
proposed rule. The proposals contained in this notice may be changed in 
light of the comments received.
    Comments are specifically invited on the overall regulatory, 
economic, environmental, and energy aspects of the proposed 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 summarizing each FAA-public contact concerned with 
the substance of this proposal 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 95-ANE-21.'' The postcard will be date stamped and 
returned to the commenter.

Availability of NPRMs

    Any person may obtain a copy of this NPRM by submitting a request 
to the FAA, New England Region, Office of the Assistant Chief Counsel, 
Attention: Rules Docket No. 95-ANE-21, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received reports of 
three uncontained power turbine (PT) disk failures on AlliedSignal 
Engines (formerly Textron Lycoming) LTS101 series turboshaft engines. 
These PT disk failures were caused by No. 3 bearing failures, resulting 
in loss of rotor axial location, aft movement of the PT rotor, and PT 
shaft disengagement from the gear train drive, subsequently unloading 
the PT and causing rotor overspeed. The disengagement further rendered 
the gear train drive overspeed control inoperative; therefore, the PT 
overspeed progressed until disk failure. This condition, if not 
corrected, could result in an uncontained engine failure due to a PT 
disk failure.
    On October 28, 1994, AlliedSignal Inc. purchased the turbine engine 
product line of Textron Lycoming.
    The FAA has reviewed and approved the technical contents of Textron 
Lycoming Service Bulletin (SB) No. LTS101A-72-50-0134, Revision 1, 
dated June 17, 1991, and SB No. LTS101B-72-50-0128, Revision 1, dated 
June 17, 1991, that describe procedures for incorporation of design 
modifications to the PT to enhance rotor retention in the event of No. 
3 bearing failure.
    At the present time, this proposed airworthiness directive (AD) 
would require only the PT rotor retention modifications for 
AlliedSignal Engines Model LTS101-600A2, -600A3, and -750B2 engines. 
AlliedSignal Engines and several airframe manufacturers have developed 
electronic overspeed system (EOS) modifications for other models of the 
AlliedSignal Engines LTS101 series turboshaft engines. These other 
modifications address additional disk failures precipitated by No. 4 
bearing failure, which in two cases led to power pinion gear failure 
and PT shaft disengagement from the power train without loss of rotor 
axial location, overspeed, and loss of PT overspeed protection. In 
separate rulemaking, the FAA will require these EOS modifications for 
these other models. Airworthiness directive 88-14-01, applicable to all 
Textron Lycoming LTS101 engines, requires repetitive inspections and 
monitoring of the lubrication system to prevent PT rotor disk failures 
due to failure of either No. 3 or No. 4 bearings. Performing the PT 
rotor and EOS modifications on these other models would constitute 
terminating action for the inspections and monitoring required by AD 
88-14- [[Page 21054]] 01. The FAA has requested that AlliedSignal 
Engines and Eurocopter France develop EOS modifications for the 
AlliedSignal Engines LTS101 models addressed in this proposed AD. When 
these modifications are available, the FAA will require these 
modifications in future rulemaking that would constitute terminating 
action to the inspection and monitoring requirements of AD 88-14-01.
    Since an unsafe condition has been identified that is likely to 
exist or develop on other products of this same type design, the 
proposed AD would require incorporation of a modified PT rotor 
retention system at the next shop visit after the effective date of 
this AD, but not later than April 30, 1996. The FAA has determined that 
by that date affected engines would have at least one scheduled shop 
visit to incorporate modifications. The actions would be required to be 
accomplished in accordance with the service bulletins described 
previously.
    The FAA estimates that 20 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 10 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. Required 
parts would cost approximately $44,400 engine. Based on these figures, 
the total cost impact of the proposed AD on U.S. operators is estimated 
to be $900,000.
    The regulations proposed herein would 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 
proposal would not have sufficient federalism implications to warrant 
the preparation of a Federalism Assessment.
    For the reasons discussed above, I certify that this proposed 
regulation (1) Is not a ``major rule'' under Executive Order 12291; (2) 
is not a ``significant rule'' under the DOT Regulatory Policies and 
Procedures (44 FR 11034, February 26, 1979); and (3) if promulgated, 
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 copy of the draft regulatory evaluation 
prepared for this action is contained in the Rules Docket. A copy of it 
may be obtained by contacting the Rules Docket at the location provided 
under the caption ADDRESSES.

List of Subjects in 14 CFR Part 39

    Air transportation, Aircraft, Aviation safety, Safety.

The Proposed Amendment

    Accordingly, pursuant to the authority delegated to me by the 
Administrator, the Federal Aviation Administration proposes to amend 
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 adding the following new 
airworthiness directive:

AlliedSignal Engines: Docket No. 95-ANE-21.

    Applicability: AlliedSignal Engines (formerly Textron Lycoming) 
Models LTS101-600A2 and -600A3 turboshaft engines installed on 
Eurocopter France (formerly Aerospatiale) Model AS-350D helicopters; 
and LTS101-750B2 turboshaft engines installed on Eurocopter France 
Model SA-366G1 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 
owner/operator must use the authority provided in paragraph (b) 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 an uncontained engine failure due to power turbine 
(PT) disk failure, accomplish the following:
    (a) Incorporate improved PT rotor retention system modifications 
in accordance with Textron Lycoming Service Bulletin (SB) No. 
LTS101A-72-50-0134, Revision 1, dated June 17, 1991, or SB No. 
LTS101B-72-50-0128, Revision 1, dated June 17, 1991, as applicable, 
at the next shop visit after the effective date of this 
airworthiness directive (AD) when the PT rotor is removed, but not 
later than April 30, 1996.
    (b) 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.

    (c) 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.

    Issued in Burlington, Massachusetts, on April 17, 1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-10594 Filed 4-28-95; 8:45 am]
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