Definition
An aircraft computer that receives pitot pressure, static pressure, and outside air temperature inputs, then calculates and outputs air data values such as airspeed, altitude, vertical speed, Mach number, and true airspeed to the flight instruments and other onboard systems.
Plain English
A small computer on the aircraft that takes in raw air pressure and temperature readings from outside and turns them into the speed and altitude numbers shown on the cockpit displays.
Context Anchor
Seen in pitot-static system and cockpit display discussions, especially when explaining how airspeed, altitude, and vertical speed indications are produced.
Derivation
‘Air data’ refers to information derived from the air around the aircraft (pressure and temperature). ‘Computer’ here means a dedicated processing unit, not a general-purpose PC. Together: a box that turns raw air measurements into useful flight numbers.
Why Pilots Care
Supplies the accurate real-time numbers required for instrument flight, autopilot operation, and flight planning; loss of ADC data forces reversion to standby instruments.
Intuition Check
Do not think of this as a general laptop-style computer. An air data computer is a dedicated aircraft unit that calculates specific flight information from air pressure and temperature inputs.
Example Sentence 1
On glass cockpit aircraft, the airspeed and altitude shown on the primary flight display come from the air data computer rather than from direct pressure lines to mechanical gauges.
Example Sentence 2
After an ADC failure the pilot cross-checked the standby airspeed indicator while continuing the approach.