Definition
A panel-mounted device, typically located on the center pedestal of a glass-cockpit aircraft, that serves as the primary interface for entering data into and retrieving data from the Flight Management System (FMS). It consists of a small display screen and an alphanumeric keypad with line-select keys, allowing the pilot to load flight plans, performance data, navigation waypoints, and other parameters used by the aircraft's automated systems.
Plain English
It is the keypad and small screen the pilot uses to type information into the aircraft's flight computer and read back what the computer is doing.
Context Anchor
Seen in aircraft with flight management or advanced navigation systems, especially when entering a route, checking a message, or reviewing flight data before and during flight.
Derivation
The name describes its two functions: it is a unit for both controlling (entering commands and data) and displaying (showing system information). Calling it 'control display' rather than just 'keypad' or 'screen' signals that it does both jobs in one device.
Why Pilots Care
It enables precise route entry and reduces pilot workload during navigation tasks.
Analogy
It works like a keyboard and screen for a specialized aircraft computer: the pilot uses it to put information in and read information out.
Intuition Check
Do not think of the Control Display Unit as the whole navigation system. It is mainly the pilot’s control panel and display for working with that system.
Example Sentence 1
Before pushback, the first officer entered the route and cruise altitude into the Control Display Unit.
Example Sentence 2
During cruise the crew cross-checked the route on the Control Display Unit against the printed flight plan.