Survey of Computers in Aviation
Written by Dave Barth, April 2003
Introduction
Computers have been built in all sizes and for a multitude of purposes. There are two main types of computers: multi-purpose and special purpose.
Multi-Purpose Computers
Multi-purpose computers are those like mainframe computers used by large corporations and government entities as well as desktop personal computers.
Special-Purpose Computers
Special purpose computers are designed to do one or a few specific tasks. They are not capable of doing a wide range of functions as are personal computers or mainframes.
History of Computers
Mechanical Computers
The earliest computers were based on mechanical gears and levers to make simple decisions. The census of 1900 used cards that passed through a machine to tabulate the count. The military used special purpose mechanical computers in the 1930s to compute the elevation needed for a gun barrel to shoot a given distance.
Electronic Computers
The first electronic computers used vacuum tubes, and several of these, built by IBM, were employed at Los Alamos, New Mexico to solve equations needed to build the first atomic bomb.
Automobile Computers
Since the 1980s, automobiles have used special purpose computers to control engine operations such as the fuel/air mixture ratio, automatic braking system (ABS) control, and efficient automatic transmission shifting.
Computers in Home Appliances
Modern home appliances have small, special-purpose computers to control the specific functions required to make them work.
The Transistor
The invention of the transistor in the 1950s revolutionized computers, eliminating the need for the large, heat-producing vacuum tubes. The first transistors were enclosed in a small metal container the size of a pencil eraser. Each metal container had three wires coming out of it that required electrical input to run the transistor. In the 1960s, the technology to build many transistors into a single wafer was perfected, and that led the way to the modern central processing unit (CPU) chips in use today.
Computers in Aviation
Special purpose computers have found their way into many devices in the home as well as airplanes. Aircraft engines use them to control fuel flow to save money and make engines run efficiently. They are used for navigation in global positioning systems (GPS) and inertial navigation systems (INS).
Autopilots
Autopilots use computers to fly a plane enroute to the destination on the correct course and at the correct altitude.
Automatic Landing Systems
Automatic landing systems use computers that can fly an approach to an airport, land the plane, and taxi off the runway.
Glass Cockpits
Glass cockpits consist of computer monitors that have replaced most of the mechanical flight indicators used in earlier airlines. The monitors can display a wide
range of information including engine performance, fuel levels in the various tanks, the route to the destination, etc.
Fly-By-Wire
Fly-by-wire aircraft control systems are now being used in Airbus Industries and Boeing planes. Three computers crosscheck each other. If one of the three is not
in agreement with the other two computers, it is automatically removed from the control system. These systems take input from the pilot and copilot controls in the
cockpit and send electrical signals to motors on the wings and in the tail to move the control surfaces. This eliminates the need to run hydraulic lines to the ailerons,
rudder, and elevator.
Air Traffic Control Computers
Air traffic control centers use computers to display aircraft paths across the country. Information boxes can be displayed beside the flight path of each airplane
that show the direction, flight number, and other data.
Anti-Collision System Computers
Anti-collision systems are installed in air traffic control centers and in most large airplanes. These systems warn if airplane paths are converging and could result
in a midair collision or a near miss.
Airline Reservation Systems
Airline reservation systems use computers to issue seat reservations and keep track of them throughout each passenger?s trip. Examples are United Airlines?
Galileo system and Sabre, used by other airlines.
Military Computers
The military now uses computer-controlled smart bombs, cruise missiles, and reconnaissance aircraft. It is experimenting with computer-controlled, unmanned
fighter and bomber aircraft.