FCC

Flight Control Computer

There are two flight control computers that control the two autopilots:

1. FCC A → autopilot A
2. FCC B → autopilot B

The FCCs process inputs from the:

• MCP
• FMCs
• Auto throttle
• Control column/wheel position
• Autopilot actuator

These inputs are used to generate flight director commands and drive the respective flight control actuators. The FCCs also provide commands to:

• Speed trim
• Mach trim
• APA
• Autopilot disengage warning

In general, only one FCC will be controlling the FDs and the autopilots. However, both FCCs control the aircraft when:

• In TO/GA below 400 AGL
• When APP is engaged and LOC/GS are both captured