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