The PUSHER INTR switch installed on the co-pilot’s control wheel stops the operation of the stick pusher servo.
The electrical clutch remains engaged and makes movement of the control column heavy.
2.6
AOA Transmitter
The left and right AOA transmitters detect the angle of the aircraft pitch attitude in relation to the airflow and give
aircraft pitch-angle signals to the stick pusher computer. They are on the leading edge of the wings at rib 16. The
AOA transmitter and its mounting plate are electrically heated, refer to AMM 12-B-30-30-00-00A-040A-A. On the
rear of the AOA transmitter is an electrical connector.
The stick pusher computer supplies the AOA transmitter with a reference voltage of 6 VAC, 2500 Hz. The AOA
transmitter supplies the stick pusher computer with sine and cosine signals which are relative to the position of the
vane on the transmitter. The vane is attached by a spindle to the side of the transmitter. As the vane turns to stay
aligned with the airflow it causes the sine and cosine output signals to change.
2.7
Torque Transducer
The torque transducer detects the pressure of the oil in the torquemeter chamber and sends the signals to the stick
pusher computer. The oil pressure is in proportion to the engine torque. The torque transducer is installed on the
engine on the top of the reduction gearbox casing. It gets an excitation supply from the stick pusher computer.
2.8
PUSHER Test Switch
The PUSHER test switch is used to do a test of the stall warning and pusher functions of the system. The system
goes into PUSHER ICE MODE operation when the PUSHER test switch is pressed. It can be used in flight or on
the ground. The in-flight and on-ground tests operate differently.
The PUSHER TEST push switch is on the TEST section of the Overhead Control Panel refer to AMM 12-B-31-10-
00-00A-040A-A.
2.9
Power Control Lever (PCL) Switch
The PCL switch is a two position switch which gives a ground signal to the stick pusher computer when the PCL is
set to IDLE. The switch is installed in the center console. When the PCL is set to IDLE the stick pusher computer
disables the monitoring of the engine torque and engine running signals. This prevents incorrect operation of the
amber PUSHER message on the CAS display.
3
Operation - Stick Pusher System
Refer to Fig. 1 .
3.1
On Ground
When the electrical system is energized, the left and right WOW relays energize and connect a ground to channel 1
and channel 2 of the stick pusher computer. This disables the stick shaker actuator, the stick pusher servo and the
stall warning tone during normal operation. They are enabled for the system test.
3.2
In Flight
The stick shaker and aural stall warning tone circuits are enabled immediately after take-off. The stick pusher circuit
is enabled five seconds after take-off.
PC-12/47E AMM Doc No 02300, ISSUE 01 REVISION 26 MSN 545, 1001-1719,
1721-1999
12-B-AM-00-00-00-I
UNCLASSIFIED
Effectivity: All
12-B-22-20-00-00A-040A-A
UNCLASSIFIED
2021-12-04 Page 5
