JNTU B.Tech III AIRCRAFT SYSTEMS AND CONTROLS Previous Question Paper (March-2021 - R18)

The core avionic system serves as the central nervous system of an aircraft, integrating various subsystems to ensure safe flight, navigation, and mission success. The primary subsystems include:

• Communication Systems: Equipment for air-to-ground and air-to-air voice and data links, including VHF, UHF, and satellite communication (SATCOM) units.
• Navigation Systems: Sensors and processors like GPS, Inertial Reference Systems (IRS), VOR, ILS, and TACAN that provide precise position, velocity, and attitude data.
• Flight Management System (FMS): The central computer that manages flight plans, performance optimization, and fuel management.
• Display and Control Systems: Electronic Flight Instrument Systems (EFIS), Head-Up Displays (HUD), and Multi-Function Displays (MFD) that present critical data to the pilot.
• Air Data Systems: Sensors providing altitude, airspeed, and angle-of-attack data via pitot-static probes and air data computers.
• Surveillance and Identification Systems: Weather radar, Traffic Collision Avoidance Systems (TCAS), and Transponders (IFF) for situational awareness.
• Data Recording Systems: Flight Data Recorders (FDR) and Cockpit Voice Recorders (CVR) for post-flight analysis.

An Integrated Avionic System is an architecture where multiple avionic functions—such as navigation, communication, flight control, and monitoring—are consolidated into a unified network of shared processors, sensors, and displays. Unlike federated systems where each function has dedicated hardware, integrated systems utilize high-speed data buses (like ARINC 664 or MIL-STD-1553) to share information, reducing weight, power consumption, and maintenance complexity.

Environmental conditions significantly impact performance:

• Temperature Extremes: High temperatures can lead to thermal degradation of semiconductors and failure of cooling systems, while extremely low temperatures can cause mechanical stiffness in moving parts or brittle failure of components.
• Vibration and Shock: Constant vibration from engines and turbulence can cause fatigue in solder joints, connector loosening, and micro-cracking in circuit boards, leading to intermittent signal loss.
• Humidity and Corrosion: High humidity promotes condensation on circuit boards, resulting in short circuits, electrical leakage, and long-term corrosion of metallic contacts.
• Electromagnetic Interference (EMI): Variations in atmospheric electricity and external radiation can induce noise in sensitive sensors, potentially corrupting data streams if shielding is inadequate.
• Pressure Changes: Rapid changes in altitude affect cooling efficiency (due to lower air density) and can cause dielectric breakdown in high-voltage components.