What does SAS stand for in helicopter systems?

• A. Structural Adjustment System
• B. Safety Assurance System
• C. Stabilization Autopilot System
• D. Stability Augmentation System

Answer: (D)

The key idea is that SAS stands for Stability Augmentation System. This is a flight-control subsystem that automatically adds damping to the helicopter’s attitude and angular motions, helping to keep the aircraft steady and easier to control. It uses sensor data from gyros and accelerometers and then commands small, timely adjustments through the rotor controls to counteract unwanted roll, pitch, and yaw motions. The result is reduced pilot workload and more stable handling, especially in gusty conditions or during hover.

Stability augmentation is different from an autopilot. An autopilot would steer the helicopter along a commanded flight path, whereas SAS focuses on damping and stabilizing the aircraft’s motion, making it easier for the pilot to maintain precise control. In some contexts, you might see Stabilization Augmentation System used interchangeably, but Stability Augmentation System is the standard term.