LCA Tejas Technology

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ejas is equipped with a quadruplex digital fly-by-wire flight control system to ease handling by the pilot. The digital FBW system of the Tejas employs a powerful digital flight control computer (DFCC) comprising four computing channels, each with its own independent power supply and all housed in a single LRU. The DFCC receives signals from a variety of sensors and pilot control stick inputs, and processes these through the appropriate channels to excite and control the elevons, rudder and leading edge slat hydraulic actuators. The DFCC channels are built around 32-bit microprocessors and use a subset of the Ada programming language for software implementation. The computer interfaces with pilot display elements like the MFDs through MIL-STD-1553B multiplex avionics data buses and RS-422 serial links.

Tejas is intentionally made longitudinally unstable to enhance maneuverability. The Control laws (CLAW) recover Stability and provide good Handling Qualities to the Pilot. They also provide invariant response with respect to variation in aerodynamics, fuel etc. and facilitate robust performance. The CLAW is carefree and ensures that various aircraft parameters are limited automatically. This enables the pilot to fly the mission without worrying about exceedence of parameters beyond a safe limit.

The autopilot provides pilot relief functions. This helps the pilot to do more head down activities (especially mission critical activities) without being concerned about the aircraft departing from its flight path. The autopilot is also equipped with advanced features like auto level (which helps the pilot recover the aircraft if he gets disoriented and also during night flying), safe altitude recovery (which automatically pulls up the aircraft if it comes too close to the ground) and navigation modes (which steer the aircraft automatically along a pre-determined flight path).