-
In degraded mode indicated by the ELAC: The FAC computes the yaw damper function and generates a simplified law of Dutch roll damping (alternate law). This law, which has a fixed and limited authority plus or minus 5 deg., only uses gains function of the selected positions of the flaps and slats.
(2)
Automatic mode As soon as the AP is engaged, the yaw damper operates in the mode given below:
-Dutch roll damping except in approach phase
-Turn coordination to reduce the sideslip in turn.
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Interconnections between FAC and Yaw Damper Servo-Actuator
Figure 003
1EFF : ALL 1 22-63-00Page 5 1 1 Feb 01/98 1 1 1CES 1 These two orders are inhibited during the landing phase and
accomplished directly in the AP guidance orders.
-Assistance in engine failure recovery from a lateral acceleration signal through a threshold
-Accomplishment of the guidance orders : align and roll out.
B. Structure of Yaw Damper Control-Law
(Ref. Fig. 004)
R **ON A/C 001-049, 051-099, 101-149, 151-199, 201-299, 401-499,
The control law generates a deflection order to control the yaw damper servo-actuator:
-
From the position of the position feedback in synchronization
-
From the ELAC deflection order
-
From an alternate law based on a wash-out yaw-rate term with a gain function of the flap and slat configuration. The whole law is limited to a safety value (plus or minus 5 deg.).
-
From the aileron deflection order on the AP for turn coordination
-
From the landing guidance order on the yaw axis delivered by the AP
-
From a Dutch-roll damping law. This law uses a wash-out yaw-rate term and a phase advance term applied in clean configuration.
-
From a term of assistance in engine failure recovery. This term uses a
lateral acceleration term through a threshold. All these control orders are limited in speed and in amplitude.
**ON A/C 301-399,
The control law generates a deflection order to control the yaw damper servo-actuator:
-
From the position of the position feedback in synchronization
-
From the ELAC deflection order
-
From an alternate law based on a wash-out yaw-rate term with a gain function of the flap and slat configuration. The whole law is limited to a safety value (plus or minus 5 deg.).
-
From the aileron deflection order on the AP for turn coordination
-
From the landing guidance order on the yaw axis delivered by the AP
-
From a Dutch-roll damping law. This law uses a wash-out yaw-rate term and a phase advance term applied in clean configuration.
-
From a term of assistance in engine failure recovery. This term uses a
lateral acceleration term through a threshold. This threshold is zero. All these control orders are limited in speed and in amplitude.
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Yaw Damper Control-Law
Figure 004
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1 1 Feb 01/98
1 1
1CES 1
**ON A/C ALL
C. Operating Logic
The activation of the yaw damper function depends on:
-
The engagement status of the FLT CTL/FAC pushbutton switch
-
The logic of the modes (AP engaged or not, ELAC in normal mode or not, status of the ADIRS etc.)
-
The monitoring specific to the function:
computation comparators and power comparators
-
The global monitoring of the computer.
The correct operation of the mode is checked:
-
For the ELAC: if the normal law is not executed. The ELAC then turns to the standby law on the roll axis.
-
For the AP: if the acquisition of the AP-engaged signal is not correct or if the status of the peripherals does not allow the achievement of the function (dual failure of the ADIRS). The AP disconnects and the system returns to the manual mode without FAC disconnection.
The loss of the yaw damper function is indicated on the display unit of the ECAM system:
-Loss of one channel:
YAW DAMPER 1 or 2 amber warning
-Total loss:
YAW DAMPER 1 + 2 amber warning + chime.
D. Monitoring of Yaw Damper Function (Ref. Fig. 005) The block diagram given below shows the organization of this function and the various types of monitoring which are integrated. These are: 中国航空网 www.aero.cn 航空翻译 www.aviation.cn 本文链接地址：A320飞机维护手册 AMM AUTO FLIGHT 自动飞行2(27)
