TM 55-1520-240-T
CHAPTER 4
POWERPLANT SYSTEM TROUBLESHOOTING
CHAPTER OVERVIEW
Chapter 4 contains procedures for Powerplant 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 Powerplant System.
Refer to TM 55-1520-240-23 for required maintenance procedures.
SYSTEM
PARA
ENGINE PERFORMANCE CHECK (WITHOUT 74 )
4-1
ENGINE ANTI-ICING SYSTEM (WITHOUT 74 )
4-2
ENGINE LOW OIL LEVEL WARNING SYSTEM (WITHOUT 74 )
4-3
ENGINE START AND IGNITION SYSTEM (WITHOUT 74 )
4-4
GAS PRODUCER CONTROL SYSTEM (N1) (WITHOUT 74 )
4-5
POWER TURBINE CONTROL SYSTEM (N2) (WITHOUT 74 )
4-6
ENGINE ACCESSORY GEARBOX CHIP DETECTORS
(WITHOUT 74 )
4-7
SYSTEM
PARA
ENGINE PERFORMANCE CHECK (WITH 74 )
4-8
ENGINE LOW OIL LEVEL WARNING SYSTEM (WITH 74 )
4-9
ENGINE START AND IGNITION SYSTEM (WITH 74 )
4-10
GAS PRODUCER CONTROL SYSTEM (N1) (WITH 74 )
4-11
FULL AUTHORITY DIGITAL ELECTRONIC CONTROL (FADEC)
(WITH 74 )
4-12
ENGINE ACCESSORY GEARBOX CHIP DETECTORS (WITH
74 )
4-13
FAILURE SYMPTOM LIST
ENGINE PERFORMANCE CHECK (WITHOUT 74 )
SYMPTOM
TASK
DUAL ENGINE BEEP TRIM INCORRECT, ROTOR RPM BE-
TWEEN 94-96 PERCENT WITH ECL AT FLIGHT
4-1.1
NO. 1 ENGINE HIGH PTIT READING DURING START OR HOT
START
4-1.1
NO. 1 ENGINE GROUND IDLE SPEED BELOW 60 TO 63 PER-
CENT RPM
4-1.1
NO. 1 OR NO. 2 ENGINE HIGH PTIT
4-1.1
SYMPTOM
TASK
ENG NO. 1 OR NO. 2 ANTI-ICE CIRCUIT BREAKER WILL NOT
STAY CLOSED
4-2.4
SYMPTOM
TASK
NO. 1 OR NO. 2 ENGINE N2 OVERSPEED OCCURS WHEN
ECL IS MOVED FROM GROUND IDLE TO FLIGHT
4-1.1
NO. 1 OR NO. 2 ENGINE OIL TEMP HIGH
4-1.1
NO. 1 OR NO. 2 ENGINE ROUGH OR SURGING ACCELERA-
TION FROM GROUND IDLE TO FLIGHT
4-1.1
ENGINE ANTI-ICE SYSTEM (WITHOUT 74 )
SYMPTOM
TASK
NO. 1 ENGINE ANTI-ICING VALVE DOES NOT OPERATE
(CLICK NOT HEARD)
4-2.4
ENGINE LOW OIL LEVEL WARNING (WITHOUT 74 )
SYMPTOM
TASK
NO. 1 OR NO. 2 ENGINE LOW OIL CAUTION LIGHTS DO NOT
COME ON
4-3.3
SYMPTOM
TASK
NO. 2 ENGINE GROUND IDLE SPEED BELOW 60 TO 63 PER-
CENT RPM
4-1.1
ROTOR RPM CHANGES MORE THAN +0 OR -2 PERCENT
OR ENGINE TORQUE SPLIT EXCEEDS 6 PERCENT DURING
HOVER
4-1.1
SYMPTOM
TASK
NO. 2 ENGINE ANTI-ICING VALVE DOES NOT OPERATE
(CLICK NOT HEARD)
4-2.4
Change 17 4-2.1
