AD 95-08-14

This amendment adopts a new airworthiness directive (AD) that is applicable to AlliedSignal, Inc. (formerly Textron Lycoming) LTS101 series turboshaft engines. This action requires a one-time replacement of magnetic speed pickups in the engine electronic overspeed protection system, or inspection, and replacement, if necessary, of pickups with incorrect polarity. This amendment is prompted by reports of a manufacturing error that resulted in improper sensor polarity of magnetic speed pickups. The actions specified in this AD are intended to prevent the engine electronic overspeed protection system from failing to function as designed, which can result in the inability to arrest an uncontrolled power turbine (PT) rotor overspeed and damage to the aircraft.

Final rule; request for comments.

95-08-14 AlliedSignal, Inc.: Amendment 39-9203. Docket 94-ANE-58.
Applicability: AlliedSignal, Inc. (formerly Textron Lycoming) Models LTS101-650B1, -750B1, -650C3/3A, and -750C1 turboshaft engines incorporating engine electronic overspeed protection system installed in production prior to the effective date of this airworthiness directive (AD), or retrofitted in accordance with Textron Lycoming Service Bulletin (SB) No. LTS101B-73-10-0127, Revision 2, dated August 14, 1992, or previous revisions; or SB No. LTS101C-73-10-0129, Revision 3, dated August 14, 1992, or previous revisions. These engines are installed on but not limited to Messerschmitt-Bolkow-Blohm BK117 series and Bell Helicopter Textron 222 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, orrepaired 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 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 the engine electronic overspeed protection system from failing to function as designed, which can result in the inability to arrest an uncontrolled power turbine (PT) rotor overspeed and damage to the aircraft, accomplish the following:
(a) Within 150 hours time in service afterthe effective date of this AD, accomplish either paragraph (a)(1) or paragraph (a)(2) of this AD.
(1) Replace magnetic speed pickups, P/N 4-301-356-01, in the engine electronic overspeed protection system, with a serviceable part in accordance with AlliedSignal Engines SB No. LTS101-73-10-0169, dated December 12, 1994.
(2) Inspect magnetic speed pickups, P/N 4-301-356-01, in the engine electronic overspeed protection system, for polarity in accordance with AlliedSignal Engines SB No. LTS101- 73-10-0169, dated December 12, 1994, and prior to further flight, remove magnetic speed pickups with incorrect polarity, and replace with a serviceable part, in accordance with AlliedSignal Engines SB No. LTS101-73-10-0169, dated December 12, 1994.
(b) Prior to installation, inspect all uninstalled magnetic speed pickups, P/N 4-301-356-01, for polarity, and replace pickups with incorrect polarity with a serviceable part, in accordance with AlliedSignal Engines SB No. LTS101-73-10-0169, dated December 12, 1994.
(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 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 inspection, and replacement, of the magnetic speed pickups shall be done in accordance with the following AlliedSignal Engines service document:

Document No.
Pages
Date
SB No. LTS101- 73-10-0169
1-3
December 12, 1994
Total pages: 3.

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; telephone (203) 385-1470, fax (203) 385-2256. 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 9, 1995.

The Federal Aviation Administration (FAA) has received reports of a manufacturing error that resulted in improper sensor polarity of magnetic speed pickups on certain AlliedSignal, Inc. (formerly Textron Lycoming) Models LTS101-650B1, -750B1, -650C3/3A, and -750C1 turboshaft engines. These engines incorporate an engine electronic overspeed protection system installed in production or retrofitted in accordance with Textron Lycoming Service Bulletin (SB) No. LTS101B-73-10-0127, Revision 2, dated August 14, 1992, or previous revisions; or SB No. LTS101C-73-10-0129, Revision 3, dated August 14, 1992, or previous revisions. The engine electronic overspeed protection system utilizes signals from two magnetic pickups to sense and arrest power turbine (PT) rotor overspeed. The improper sensor polarity induced by the manufacturing error can result in a malfunctioning engine electronic overspeed protection system although the system self-test indicates normal operation. This condition, if not corrected, could result in the engine electronic overspeed protection system failing to function as designed, which can result in the inability to arrest an uncontrolled PT rotor overspeed and damage to the aircraft.
The FAA has reviewed and approved the technical contents of AlliedSignal Engines SB No. LTS101-73-10-0169, dated December 12, 1994, that describes procedures for a one-time replacement of magnetic speed pickups in the engine electronic overspeed protection system, or inspection, and replacement, if necessary, of pickups with incorrect polarity.
Since an unsafe condition has been identified that is likely to exist or develop on other AlliedSignal, Inc. LTS101 series engines of the same type design, this airworthiness directive (AD) is being issued to prevent the engine electronic overspeed protection system from failing to function as designed. This AD requires a one-time replacement of magnetic speed pickups in the engine electronic overspeed protection system, or inspection, and replacement, if necessary, of pickups with incorrect polarity. The actions are required to be accomplished in accordance with the service bulletin described previously.
Since a situation exists that requires the immediate adoption of this regulation, it is found that notice and opportunity for prior public comment hereon are impracticable, and that good cause exists for making this amendment effective in less than 30 days. Comments Invited
Although this action is in the form of a final rule that involves requirements affecting flight safety and, thus, was not preceded by notice and an opportunity for public comment, comments are invited on this rule. Interested persons are invited to comment on this 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 under the caption "ADDRESSES." All communications received on or before the closing date for comments will be considered, and this rule may be amended in light of the comments received. Factual information that supports the commenter's ideas and suggestions is extremely helpful in evaluating the effectiveness of the AD action and determining whether additional rulemaking action would be needed.
Comments are specifically invited on the overall regulatory, economic, environmental, and energy aspects of the rule that might suggest a need to modify the 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 that summarizes each FAA-public contact concerned with the substance of this AD 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 94-ANE-58." The postcard will be date stamped and returned to the commenter.
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.
The FAA has determined that this regulation is an emergency regulation that must be issued immediately to correct an unsafe condition in aircraft, and is not a "significant regulatory action" under Executive Order 12866. It has been determined further that this action involves an emergency regulation under DOT Regulatory Policies and Procedures (44 FR 11034, February 26, 1979). If it is determined that this emergency regulation otherwise wouldbe significant under DOT Regulatory Policies and Procedures, a final regulatory evaluation will be prepared and placed in the Rules Docket. A copy of it, if filed, 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. App. 1354(a), 1421 and 1423; 49 U.S.C. 106(g); and 14 CFR 11.89. 39.13 - [AMENDED]
2. Section 39.13 is amended by adding the following new airworthiness directive: