Alternate Stability Augmentation System (ASAS)

Note: The alternate stability augmentation system is not supported in this software version.

On the real aircraft, the alternate stability augmentation system (ASAS) [10-11, fig. 5-2] provides damping inputs to the aerodynamic flight control system about the pitch and roll axes in case of failure of the roll axis of the SAS. Major components of the system are the pitch and roll gyros, electronic case assembly, left and right transfer relays, and left and right serve position transducers, in addition to the servo cylinders and bell cranks which are common to both the SAS and the ASAS.

When the ASAS is armed, failure of the roll channel in the SAS will automatically energize the ASAS. Change-over to the ASAS does not affect the yaw channel of the SAS, which continues to function in the normal manner. The ASAS is completely separate from the SAS and comprises a working circuit only, bypassing all SAS controls and indicators which are then inoperative (except for those in the yaw channel). To completely bypass the SAS electrical circuitry, a servo position transducer, separate from those on the SAS servo cylinders is on the left and right SAS bell cranks to transmit servo cylinder position feedback to the ASAS gyros and electronic case assembly. The ASAS is powered from the No. 2 primary AC bus and the primary DC bus.

In this section:

Alternate Stability Augmentation System Controls and Indicators