Stability and Control Augmentation System (SCAS) — The SCAS is a three-axis, limited authority rate reference augmentation system. The SCAS cancels undesired motion of the helicopter during flight. This is accomplished by inducing an electrical input into the flight control system to augment the pilot mechanical input.
The SCAS control panel contains a POWER switch for applying dc (essential bus) and ac power to the system. The circuits are protected by the SCAS POWER dc and SCAS PWR ac circuit breakers. The panel also contains three channel engage switches which energize electric solenoid valves controlling hydraulic pressure to the system. The panel has three amber colored NO-GO lights, one associated with each PITCH, ROLL and YAW channel engage switch. These lights are illuminated during the warm-up to indicate the presence of current in each associated channel actuator. Should an engagement be attempted during this warm-up period, the actuator may make an abrupt input to the flight controls at the moment of engagement. When engagement is made, the NO-GO lights are locked out of the circuit and do not operate as malfunction indicators. Disengaging a channel, however, restores the associated light to operation. The NO-GO lights have a built-in press-to-test feature for ensuring that the indicator is operational, but this feature works only prior to channel engagement.
Updated: 12 January 2008 | Born on 18 March 1999 |