TM 55-1520-240-T
CHAPTER 8
INSTRUMENT SYSTEM TROUBLESHOOTING
CHAPTER OVERVIEW
Chapter 8 contains procedures for Instrument System troubleshooting. Each system and failure symptom is listed below. Included in this chapter are locations and views of all electrical
connectors, receptacles, relays, and ground connections for the Instrument System.
Refer to TM 55-1520-240-23 for required maintenance procedures.
SYSTEM
PARA
PITOT STATIC SYSTEM
8-1
GAS PRODUCER TACHOMETER SYSTEM
8-2
ENGINE OIL PRESSURE INDICATING SYSTEM
8-3
ENGINE OIL TEMPERATURE INDICATING SYSTEM
8-4
PTIT SYSTEM
8-5
TORQUE INDICATING SYSTEM
8-6
HYDRAULIC PRESSURE INDICATING SYSTEM
8-7
HYDRAULIC OIL TEMPERATURE INDICATING SYS-
TEM
8-8
SYSTEM
PARA
TRANSMISSION OIL PRESSURE INDICATING AND
WARNING SYSTEM
8-9
TRANSMISSION OIL TEMPERATURE INDICATING
AND WARNING SYSTEM
8-10
FUEL QUANTITY INDICATING SYSTEM
8-11
CRUISE GUIDE INDICATING SYSTEM
8-12
TURN AND SLIP INDICATORS
8-13
MAINTENANCE PANEL POWER DISTRIBUTION
8-14
ROTOR TACHOMETER
8-15
ENGINE FUEL FLOW INDICATING SYSTEM
8-16
FAILURE SYMPTOM LIST
PITOT STATIC SYSTEM
SYMPTOM
TASK
AIMS ALT CIRCUIT BREAKER WILL NOT STAY
CLOSED
8-1.4
NO HEAT FELT ON LEFT OR RIGHT PITOT TUBE,
PITOT SWITCH AT ON
8-1.4
NO HEAT FELT ON LOWER RIGHT OR LOWER LEFT
SIDESLIP PORTS
8-1.4
NO. 1 GAS PRODUCER TACHOMETER READS 0 PER-
CENT RPM WHEN NO. 1 ENGINE IS MOTORED
8-2.3
NO. 2 GAS PRODUCER TACHOMETER READS 0 PER-
CENT RPM WHEN NO. 2 ENGINE IS MOTORED
8-2.3
SYMPTOM
TASK
NO HEAT FELT ON UPPER RIGHT OR UPPER LEFT
SIDESLIP PORTS
8-1.4
NO. 1 OR NO. 2 PITOT SYSTEM LEAKS
8-1.4
NO. 1 OR NO. 2 SIDESLIP SYSTEM LEAKS
8-1.4
PILOT OR COPILOT ALTIMETER VIBRATOR DOES
NOT OPERATE
8-1.4
GAS PRODUCER TACHOMETER SYSTEM
NO. 1 ENGINE GAS PRODUCER TACHOMETER
READING FLUCTUATES OR IS ERRATIC
8-2.3
NO. 2 ENGINE GAS PRODUCER TACHOMETER
READING FLUCTUATES OR IS ERRATIC
8-2.3
SYMPTOM
TASK
PITOT HEAT CIRCUIT BREAKER WILL NOT STAY
CLOSED
8-1.4
PITOT STATIC SYSTEM LEAKS
8-1.4
YAW PORT HEAT CIRCUIT BREAKER WILL NOT
STAY CLOSED
8-1.4
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Change 7 8-2.1
