AD 96-12-27

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

Final rule.

96-12-27 AlliedSignal Inc.: Amendment 39-9668. Docket 93-ANE-64.
Applicability: AlliedSignal Inc. (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 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 (b) 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 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 with4,501 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.
(d) The actions required by this AD shall be done in accordance with the following SB:

Document No.
Pages
Revision
Date
Textron Lycoming SB No. LT 101-72-50-0150
1-6
Original
September 1, 1993
Total Pages: 6.

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, 111 South 34th Street, Phoenix, AZ 85072; telephone (602) 365-2493, fax (602) 365-2210. 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.
(e) This amendment becomes effective on August 19, 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) LTS 101 series turboshaft and LTP 101 series turboprop engines was published in the Federal Register on May 15, 1995 (60 FR 25869). That action proposed to require a one-time inspection of the disk tenon area of the gas generator turbine disk in accordance with Textron Lycoming Service Bulletin (SB) No. LT 101-72-50-0150, dated September 1, 1993.
Interested persons have been afforded an opportunity to participate in the making of this amendment. No comments were received on the proposal or the FAA's determination of the cost to the public. The FAA has determined that air safety and the public interest require the adoption of the rule as proposed.
The FAA estimates that 618 engines installed on aircraft of U.S. registry will be affected by this AD, that it willtake approximately 6.5 work hours per engine to accomplish the required actions, and that the average labor rate is $60 per work hour. AlliedSignal Inc. 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 AD on U.S. operators is estimated to be $229,896.
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 USC 106(g), 40113, 44701. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following newairworthiness directive: