The Mode Control Panel (MCP) controls an advanced autopilot and related systems such as an automated flight director system (AFDS) or an auto-throttle system. MCP's are given various names by different aircraft manufacturers.
The MCP is so called because it contains controls that allow the crew of the aircraft to select which parts of the aircraft's flight are to be controlled automatically. In modern MCPs, there are many different modes of automation available. The mode selector controls are used to choose roll and pitch modes for the autopilots and to activate or deactivate the auto-throttles where installed. Basic inputs such as heading, speed, vertical speed, flight level/altitude can be input. Once these modes have been selected as active, the aircraft computers will then adjust the pitch attitude, heading and thrust to achieve the selected parameters. Use of these modes does not necessarily require a vertical or lateral profile to be input into the FMS.
The MCP can be used to instruct the autopilot to hold a specific altitude, to change altitudes at a specific rate, to hold a specific heading, to turn to a new heading, to follow the directions of a flight management computer (FMC), and so on. The MCP is actually independent of the autopilot—it simply sets the mode in which the autopilot operates, but the autopilot itself (e.g., an AFDS) is a separate aircraft system. The MCP often interacts with both the AFDS or autopilot and the FMC(s).
MCPs are often mounted on the glare shield, a small panel that overhangs the main instrument panel of the aircraft and also functions as a shield against outside glare.