Definition
A number system that uses only two digits, 0 and 1, to represent all values. Each digit position represents a power of two, so counting goes 0, 1, 10, 11, 100, 101, and so on. It is the number system used internally by digital electronics and aircraft computer systems, where 0 and 1 correspond to two distinct electrical states (off/on, low/high voltage).
Plain English
A way of writing numbers using only two symbols, 0 and 1, instead of the ten symbols (0–9) we normally use. Computers work this way because electronic circuits can easily detect two states: off or on.
Context Anchor
Seen in aircraft electrical, electronic, and avionics system training, especially when learning how digital circuits, fault codes, and computer-controlled components handle information.
Derivation
From the Latin 'binarius', meaning 'consisting of two'. The name simply reflects that the system is built from two digits.
Why Pilots Care
Modern aircraft systems — autopilots, flight management computers, glass cockpit displays — all process information in binary internally. Understanding that digital systems represent every value as patterns of 0s and 1s helps when troubleshooting fault codes, data bus messages, or memory-related issues.
Analogy
Think of a row of light switches. Each switch is either off (0) or on (1). With enough switches in a row, you can represent any number you like just by which ones are on and which are off.
Intuition Check
Binary does not mean “simple” or “either-or” in a loose everyday sense here. It means a specific number system that uses only two digits: 0 and 1.
Example Sentence 1
The technician explained that the flight computer stores all sensor data in the binary number system before converting it for display.
Example Sentence 2
Aircraft computers store and process all flight data using the binary number system.