DOC AIRBUS | AMM A320FRUDDER TRIM ACTUATION - DESCRIPTION AND OPERATION
** ON A/C NOT FOR ALL
** ON A/C NOT FOR ALL
1. General
The rudder trim control is electrically signalled. An electric actuator installed in the tail area drives a trim screwjack via a rotary shaft and universal joints.
The actuator is manually controlled via the FACs (Ref. ATA 22) from the control panel located on the center pedestal, at a constant speed.
A reset function initiated when you press a RESET pushbutton switch on the control panel permits to null the rudder trim position through the FACs.
The rudder trim position is shown on the control panel.
The FACs also control the trim actuator in AP mode.
** ON A/C NOT FOR ALL The rudder trim control is electrically signalled. An electric actuator installed in the tail area drives a trim screwjack via a rotary shaft and universal joints.
Trim (Rudder)The actuator is manually controlled via the FACs (Ref. ATA 22) from the control panel located on the center pedestal, at a constant speed.
A reset function initiated when you press a RESET pushbutton switch on the control panel permits to null the rudder trim position through the FACs.
The rudder trim position is shown on the control panel.
The FACs also control the trim actuator in AP mode.
NOTE: The maximum admissible rudder trim limits indicated on the control panel when the aircraft is stabilized in heading with the AP engaged are RH 1 DEG and LH 2.3 DEG.
2. Component Location
** ON A/C NOT FOR ALL | FIN | FUNCTIONAL DESIGNATION | PANEL | ZONE | ACCESS DOOR | ATA REF |
|---|---|---|---|---|---|
| ** ON A/C ALL | |||||
| 10CC | ACTUATOR-RUDDER TRIM | 325AL | 325 | 27-22-51 | |
| 9CC | CTL SW-RUDDER TRIM | 110VU | 210 | 22-62-11 | |
3. Component Description
(1) The actuator has two 3-phase asynchronous motors installed on the same shaft (but they are electrically independent and controlled by independent plug-in electronic assemblies).
The motors are permanently coupled to a reduction gear which drives the output shafts via a torque limiter.
The motors are permanently coupled to a reduction gear which drives the output shafts via a torque limiter.
(2) Non-locking rotary stops limit the actuator stroke.
(3) The main output shaft is internally duplicated by a second shaft which permits a duplicate recopy (this duplication prevents the loss of the four transducers if there is a single rupture).
(4) The output shaft drives four inductive transducer units :
- the main output shaft drives the feedback transducer unit of one channel and the monitoring transducer unit of the other channel through a reduction gear
- the internal output shaft drives the other two transducer units in the same manner.
(5) An externally-visible index on the last actuating gear of one of the transducer units shows the zero position of the output shaft.
(6) A tapered rigging pin is used to set the output shaft at mid angular travel (zero trim position and zero reference for setting of transducers).
There is no damage if a motor is energized with the pin in position.
There is no damage if a motor is energized with the pin in position.
(7) The actuator is sealed and has a desiccant patch, the color of which is externally visible.
(8) Electronic assembly :
- a monitoring output makes the test of the electronic circuitry possible
- a monitoring power supply permits the automatic test of the electronic assembly at each FAC.
B. Maintenance
The component below is a line-replaceable unit (LRU) :
The component below is a line-replaceable unit (LRU) :
- electronic assembly
4. Control and Indicating
A. Control Panel
The RUD TRIM control panel includes :
The RUD TRIM control panel includes :
- a RUD TRIM control switch
- a RESET pushbutton switch
- a RUD TRIM indicator
(1) RUD TRIM control switch
This is a 3-position rotary switch spring-loaded to the neutral (center) position.
The direction of rudder trim travel depends on the direction of the switch rotation.
This is a 3-position rotary switch spring-loaded to the neutral (center) position.
The direction of rudder trim travel depends on the direction of the switch rotation.
(2) RESET pushbutton switch
This pushbutton switch permits to automatically reset the rudder trim to zero.
After a RESET selection through push action on the pushbutton switch, this switch returns to its initial position.
This pushbutton switch permits to automatically reset the rudder trim to zero.
After a RESET selection through push action on the pushbutton switch, this switch returns to its initial position.
(3) RUD TRIM indicator
A digital indicator (1/10 resolution) shows the rudder trim travel together with the direction (L or R).
A digital indicator (1/10 resolution) shows the rudder trim travel together with the direction (L or R).