The present world is developing rapidly in the field of electronics and communication. Tell me a place where electronics equipment are not used! Simply put, there is barely any place where electronics equipment are not found. Similarly, electronics instrument are also major part of the aircraft. A different term is used for the electronics system in aircraft which is ‘Avionics’. Avionics is also known as flight control system because it controls various aspects of aircraft.

Avionics is the science of electronics used on aircraft, artificial satellites and spacecraft. Here, we are talking about aircraft avionics and the types of equipment used. Aircraft avionic systems comprise of communications, navigation, the display and management of multiple systems, and the hundreds of systems that are fitted to aircraft in order to perform different individual functions. Generally, Avionic systems of an aircraft are located at the cockpit of the aircraft. The type of electric system used in avionic systems differ with the type of aircraft. DC electrical system of 14 or 28V is used to power the avionic system of majority of aircraft. However, some sophisticated and larger aircraft like military planes require an AC system operating at 400Hz, 115V AC.

avionics - cockpit view

Aircraft avionics include the following system;

Communication System;

The main purpose of communication system is to connect flight deck to passengers and passengers to flight deck. Similarly, on‑board communications are provided by public-address systems and aircraft intercoms. The VHF (Very High Frequency) aviation communication system works on the air band of 118.000 MHz to 136.975 MHz. Each channel is spaced from the adjacent ones by 8.33 kHz in Europe, 25 kHz elsewhere. VHF is also used for line of sight communication such as aircraft-to-aircraft and aircraft-to-ATC (Air Traffic Control). Amplitude modulation (AM) is used, and the conversation is performed in simplex mode. Aircraft communication can also take place using HF (especially for trans-oceanic flights) or satellite communication.

avionics equipments

Navigation System;

The term navigation means the process of determining the position as well as direction of the aircraft on or above the earth’s surface. For navigation, avionics uses satellite navigation system, grounded navigation system, INS (inertial navigation system) and combined navigation system. Satellite navigation system includes GPS (Global Positioning System) and WAAS (Wide Area Augmentation System). Likewise, grounded avionics system includes VOR (VHF Omni-Directional Range) or LORAN (Long-range Navigation). The main purpose of navigation systems is to calculate the position of aircraft automatically and display it to the flight crew on moving map displays.

vhf omnirange-navigation system
avionics - long range navigation

Fuel System;

Fuel control is undoubtedly the most prioritized thing in an aircraft. Avionics uses Fuel Quantity Indication System (FQIS), which monitors the amount of fuel aboard. FQIS computer uses various sensors, such as capacitance tubes, temperature sensors, densitometers & level sensors to calculate the mass of fuel remaining on board. Similarly, Fuel Control and Monitoring System (FCMS) reports fuel remaining on board in a similar manner, but, by controlling pumps & valves, also manages fuel transfers around various tanks.

avionics - high wing fuel injection system

Flight recorder;

Everyone must have heard about “black box” in an aircraft. Black box is the flight recorder system used in aircraft. Black boxes are the commercial aircraft cockpit data recorders which store flight information and audio from the cockpit. They are often recovered from an aircraft after a crash to determine control settings and other parameters during the incident. Though it is called black box, black box is actually orange in color.

 flight recorder instrument-black box

Aircraft flight control systems;

Modern aircrafts have means of automatically controlling flight known as aircraft flight control system. Nowadays most commercial planes are equipped with aircraft flight control systems in order to reduce pilot error and workload at landing or takeoff. A conventional fixed-wing aircraft flight control system comprises of flight control surfaces, the respective cockpit controls, connecting linkages, and the necessary operating mechanisms to control an aircraft’s flight direction. They are also considered as flight controls because they change speed.

Other systems

Besides the above mentioned systems avionics includes several other equipment like weathering systems such as weather radar, lightning detectors, radars, traffic alert and collision avoidance system (TCAS), glass cockpit, sonar, and the list goes on.

avionics - radar equipment

As we can see, there is an avionics system for every little thing an aircraft does. The avionics system are likely to minimize human errors and make the aircraft flight safer. However, the avionics system should be perfectly precise and accurate otherwise it may lead to appalling consequences. Therefore, multiple testing of avionics system should be done before its commercial use. In a nutshell, avionics is the heart of an aircraft and its use is a must in modern aircraft.

Check out this wikipedia link to learn about Avionics in detail.

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By Nishchal Poudel

Nishchal is currently studying Bachelor in Aerospace Engineering at IOE Pulchowk Campus, Nepal.

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