[Federal Register Volume 60, Number 93 (Monday, May 15, 1995)]
[Proposed Rules]
[Pages 25869-25871]
From the Federal Register Online via the Government Publishing Office [www.gpo.gov]
[FR Doc No: 95-11903]



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DEPARTMENT OF TRANSPORTATION

Federal Aviation Administration

14 CFR Part 39

[Docket No. 93-ANE-64]


Airworthiness Directives; AlliedSignal Engines (Formerly Textron 
Lycoming) LTS 101 Series Turboshaft and LTP 101 Series Turboprop 
Engines

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) that is applicable to AlliedSignal Engines (formerly 
Textron Lycoming) LTS 101 series turboshaft and LTP 101 series 
turboprop engines. This proposal would require removal from service of 
suspect disks for a one-time inspection of the disk tenon area of the 
gas generator turbine disk. This proposal is prompted by a report of a 
gas generator turbine disk tenon failure. The actions specified by the 
proposed AD are intended to prevent total loss of engine power, 
inflight engine shutdown, and possible damage to the aircraft.

DATES: Comments must be received by July 14, 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. 93-ANE-64, 12 New England 
Executive Park, Burlington, MA 01803-5299. Comments may be inspected at 
this location between 8 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 [[Page 25870]] Docket Number 93-ANE-64.'' 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. 93-ANE-64, 12 New England Executive Park, 
Burlington, MA 01803-5299.

Discussion

    The Federal Aviation Administration (FAA) has received a report of 
a gas generator turbine disk tenon failure on an AlliedSignal Engines 
(formerly Textron Lycoming) LTS 101 turboshaft engine. The FAA 
investigation revealed that the disk had sharp-edged grooves in the 
disk blade slots created in the broaching operations that occurred 
during manufacturing. These grooves significantly reduce the cyclic 
life of disk tenons. This condition, if not corrected, could result in 
total loss of engine power, inflight engine shutdown, and possible 
damage to the aircraft.
    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. LT 101-72-50-0150, dated September 
1, 1993, that describes procedures for removal from service of suspect 
disks for a one-time inspection of the disk tenon area of the gas 
generator turbine disk.
    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 removal from service of suspect disks for a 
one-time inspection of the disk tenon area of the gas generator turbine 
disk. The actions would be required to be accomplished in accordance 
with the service bulletin described previously.
    The FAA estimates that 618 engines installed on aircraft of U.S. 
registry would be affected by this proposed AD, that it would take 
approximately 6.5 work hours per engine to accomplish the proposed 
actions, and that the average labor rate is $60 per work hour. 
AlliedSignal Engines has advised that they will supply disks or rotors 
on an exchange basis at no cost to the operator. Based on these 
figures, the total cost impact of the proposed AD on U.S. operators is 
estimated to be $229,896.
    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 ``significant regulatory action'' under 
Executive Order 12866; (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. 93-ANE-64.

    Applicability: AlliedSignal Engines (formerly Textron Lycoming) 
LTS 101 series turboshaft and LTP 101 series turboprop engines 
installed on but not limited to Aerospatiale AS 350 and SA366G, Bell 
222, and Messerschmitt-Bolkow-Blohm (MBB) BK117 helicopters; and 
Piaggio P166-DL3 and Airtractor AT302 airplanes.

    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 total loss of engine power, inflight engine shutdown, 
and possible damage to the aircraft, accomplish the following:
    (a) Remove from service suspect disks and perform a one-time 
inspection of the disk tenon area of the gas generator turbine disk, 
and replace, if necessary, with a serviceable part, in accordance 
with Textron Lycoming Service Bulletin (SB) No. LT 101-72-50-0150, 
dated September 1, 1993, as follows:
    (1) For disks with greater than 5,000 cycles since new (CSN) on 
the effective date of this AD, remove within 235 cycles in service 
(CIS).
    (2) For disks with 4,501 to 5,000 CSN on the effective date of 
this AD, remove within 285 CIS.
    (3) For disks with 4,001 to 4,500 CSN on the effective date of 
this AD, remove within 350 CIS.
    (4) For disks with 3,501 to 4,000 CSN on the effective date of 
this AD, remove within 450 CIS.
    (5) For disks with 3,001 to 3,500 CSN on the effective date of 
this AD, remove within 600 CIS.
    (6) For disks with 2,501 to 3,000 CSN on the effective date of 
this AD, remove within 800 CIS, or prior to accumulating 3,400 CSN, 
whichever occurs later.
    (7) For disks with 2,001 to 2,500 CSN on the effective date of 
this AD, remove within 1,100 CIS, or prior to accumulating 3,400 
CSN, whichever occurs later.
    (8) For disks with less than 2,000 CSN on the effective date of 
this AD, remove prior to accumulating 3,400 CSN.
    (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 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.

    (c) 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.

    [[Page 25871]] Issued in Burlington, Massachusetts, on May 1, 
1995.
James C. Jones,
Acting Manager, Engine and Propeller Directorate, Aircraft 
Certification Service.
[FR Doc. 95-11903 Filed 5-12-95; 8:45 am]
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