AD 96-06-10

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

Final rule.

96-06-10 AlliedSignal, Inc.: Amendment 39-9547. Docket 95-ANE-21.
Applicability: AlliedSignal, Inc. (formerly Textron Lycoming) Models LTS101-600A-2 and -600A-3 turboshaft engines installed on Eurocopter France (formerly Aerospatiale) Model AS-350D helicopters; and LTS101-750B-2 turboshaft engines installed on Eurocopter France Model SA-366G1 helicopters. NOTE: This airworthiness directive (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 (c) to request approval from the Federal Aviation Administration (FAA). This approval may address either no action, if the current configuration eliminates the unsafe condition, or different actions necessaryto 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 at the next shop visit after the effective date of this airworthiness directive (AD) when the PT rotor is removed, but not later than July 1, 1996:
(a) For LTS101-600A-2 and -600A-3 turboshaft engines installed on Eurocopter France (formerly Aerospatiale) Model AS-350D helicopters, incorporate improved PT rotor retention system modifications in accordance with Section II., Accomplishment Instructions, Paragraphs A. through AT. of AlliedSignal Engines Service Bulletin (SB) No. LTS101A-72-50-0134, Revision 2, dated August 15, 1995, and concurrently replace elbow fitting in fuel control governor orifice cover Py port with tee-fitting assembly, P/N 2543854, in accordance with Section II., Accomplishment Instructions, Paragraphs C. (5) through C. (7) of AlliedSignal Engines SB No. LTS101A-73-20-166, Revision 2, dated August 1, 1995.
(b) For LTS101-750B-2 turboshaft engines installed on Eurocopter France Model SA-366G1 helicopters, incorporate improved PT rotor retention system modifications in accordance with Section II., Accomplishment Instructions, of AlliedSignal Engines SB No. LTS101B-72-50-0128, Revision 2, dated August 15, 1995.
(c) 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.
(d) 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.
(e) The modification of the PT rotor retention system shall be done in accordance with the following AlliedSignal Engines SB's:

Document No.
Pages
Revision
Date
LTS101A- 72-50-0134
1-11
2
August 15, 1995
Total pages: 11.

LTS101B- 72-50-0128
1-11
2
August 15, 1995
Total pages: 11.

LTS101A- 73-20-0166
1-6
2
August 1, 1995
Total pages: 11.

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 Engines, 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.
(f) This amendment becomes effective on May 28, 1996.

A proposal to amend part 39 of the Federal Aviation Regulations (14 CFR part 39) to include an airworthiness directive (AD) that is applicable to AlliedSignal, Inc. (formerly Textron Lycoming) LTS101 series turboshaft engines installed on Eurocopter France (formerly Aerospatiale) Model AS-350D and SA-366G1 helicopters was published in the Federal Register on June 30, 1995 (60 FR 21053). That action proposed to require incorporation of a modified power turbine (PT) rotor retention system at the next shop visit after the effective date of this AD, but not later than April 30, 1996, in accordance with 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.
Interested persons have been afforded an opportunity to participate in the making of this amendment. Due consideration has been given to the one comment received.
The commenter states that the instructions for installation of the PT retention system should be revised to require installation of two parts, inadvertently omitted but necessary to enable the pneumatic portion of the PT retention system. These parts consist of a tee-fitting to replace an existing elbow fitting in the main fuel control, and a pressurization line. The FAA concurs, and has revised the accomplishment instructions of the final rule to refer to later revisions of the applicable SB's, which reflect installation of these additional parts. Consequently, the FAA has extended the compliance timetable for the final rule in order to provide sufficient opportunity for installation of the parts, and to ensure parts availability. The FAA has determined that installation of the additional parts will not have a substantial additional impact on accomplishment of the requirements of this AD.
Since publication of the NPRM, the manufacturer has issued the following revisions to the SB's, which are referenced in thisfinal rule: AlliedSignal Engines SB No. LTS101A-72-50-0134, Revision 2, dated August 15, 1995; AlliedSignal Engines SB No. LTS101B-72-50-0128, Revision 2, dated August 15, 1995; and AlliedSignal Engines SB No. LTS101A-73-20-0166, Revision 2, dated August 1, 1995.
After careful review of the available data, including the comment 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 estimates that 20 engines installed on aircraft of U.S. registry will be affected by the requirement to install the improved power turbine rotor assembly and the power turbine retention system required by this AD, 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 to install the improved power turbine rotor assembly and the power turbine retention system required by this AD on U.S. operators is estimated to be $900,000. The FAA estimates that 60 engines installed on aircraft of U.S. registry have previously installed the improved power turbine rotor assembly and the power turbine retention system, in addition to the 20 engines in the paragraph above. Therefore, a total of 80 engines will be affected by the requirement to enable the pneumatic portion of the PT retention system by installing the tee-fitting and pressurization line. The FAA estimates that it will take approximately 2.5 work hours per engine to accomplish the required action. Required parts will cost approximately $385 per engine. Based on these figures, the total cost impact of installing the tee-fitting and pressurization line required by the AD on U.S. operators is estimated to be $42,800. Therefore, the revised total cost impact of this AD on all U.S. operators is estimated to be $942,800.
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 locationprovided 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 USC 106(g), 40113, 44701. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive: