Commonwealth legislation

AD/LTS/11 - Engine Electronic Overspeed Protection System

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Commonwealth

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legislative instrument

Plain English Summary

3/10 complexity

This airworthiness directive requires owners/operators of certain AlliedSignal (Lycoming) LTS101 turboshaft engines (those produced before 9 May 1995 or retrofitted per specified service bulletins) to inspect or replace the magnetic speed pickup PN 4-301-356-01 to confirm correct polarity, and to inspect unused pickups before installation. The action responds to a manufacturing error that can reverse sensor polarity and cause the engine electronic overspeed protection to fail; deadlines for replacement/inspection are set in the AD.

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AD/LTS/11 - Engine Electronic Overspeed Protection System

COMMONWEALTH OF AUSTRALIA (Civil Aviation Regulations 1998), PART 39 - 106 CIVIL AVIATION SAFETY AUTHORITY

SCHEDULE OF AIRWORTHINESS DIRECTIVES

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AlliedSignal (Lycoming) Turbine Engines - LTS 101 Series

AD/LTS/11 Engine Electronic Overspeed Protection System 8/95

Applicability: AlliedSignal (formerly Textron Lycoming) model LTS101-650B1, -750B1, - 650C3/3A and -750C1 engines incorporating engine electronic overspeed protection systems installed during production prior to 9 May 1995, or retrofitted in accordance with either of the following Textron Lycoming Service Bulletins (SB) or their previous revisions:

LTS101B-73-10-0127 Revision 2 dated 14 August 1992, and

LTS101C-73-10-0129 Revision 3 dated 14 August 1992.

Note: These engines are known to be installed on but not limited to Messerschmitt- Bolkow-Blohm BK117 series and Bell Helicopter Textron 222 series helicopters.

Requirement: 1. Either replace the magnetic speed pickup, part number (PN) 4-301-356-01 in the engine electronic overspeed protection system with a serviceable speed pickup, in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994, or inspect the magnetic speed pickup to determine the correct polarity in accordance with the same SB.

2. If, as a result of the Requirement 1 inspection, the magnetic speed pickup is determined to have the incorrect polarity, replace the pickup with a serviceable speed pickup in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994.

3. Inspect uninstalled magnetic speed pickups PN 4-301-356-01 in accordance with AlliedSignal Engines SB LTS101-73-10-0169 dated 12 December 1994.

Note: FAA AD 95-08-14 Amdt 39-9203 refers.

Compliance: 1. If not previously accomplished, then within 100 hours time in service from 9 June 1995.

2. Before further flight.

3. Prior to installation on an engine.

Background: AlliedSignal has advised that a manufacturing error has resulted in improper sensor polarity of magnetic speed pickups, this could cause the engine electronic overspeed protection system to fail to function as designed. Compliance with this Directive is designed to ensure that the overspeed system operates correctly.

Source text

Sourced from the Federal Register of Legislation (legislation.gov.au), CC BY 4.0.

1 AD/LTS/11 - Engine Electronic Overspeed Protection System