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AP1 ENGAGED

System study · Autoflight

From FCU Knob to FMA Readout

The FCU, the MCDU, and twin FMGCs work together to fly climbs, descents, headings, and speeds automatically — while the FMA tells you exactly what's engaged. Click through the diagram, then quiz yourself on how the autopilot, flight directors, and autothrust actually talk to each other.

Guidance chain click a component

Simplified — not for operational use. Click the MCDU, FCU, an FMGC, the autopilot, flight director, autothrust, or the FMA.
MCDU / FMS FLIGHT PLAN & PERF FCU GLARESHIELD PANEL FMGC 1 GUIDANCE + FMS FMGC 2 GUIDANCE + FMS AUTOPILOT AP1 / AP2 FLIGHT DIRECTOR FD1 / FD2 AUTOTHRUST A/THR FMA PFD MODE READOUT
Click any component above to see what it does →

When the automation lets go

MANUAL REVERSION

An autopilot disconnect can be pilot-commanded or automatic — for example if both FMGCs disagree or required sensor data is lost. The flight director and autothrust often keep working independently afterward, so pilots typically revert to hand-flying with the FD bars and A/THR still engaged, cross-checking the FMA to confirm exactly what's still active before deciding whether to keep any automation running at all.

Quick reference

AUTOPILOT (AP)

  • One AP normally engaged at a time; a second can be added for an autoland
  • Disengages via sidestick priority takeover or the red disconnect pushbutton
  • Needs valid flight director guidance, own or cross-side, to fly a mode

FLIGHT DIRECTOR / FMA

  • FD command bars work with or without the autopilot engaged
  • FMA reads left to right: thrust, vertical, lateral, then AP/FD/A-THR status
  • Armed modes and engaged modes show in different rows of the FMA

AUTOTHRUST (A/THR)

  • Thrust levers stay in a fixed detent; A/THR moves thrust electronically
  • Can be engaged independently of the autopilot and flight director
  • Reverts to manual thrust if disconnected, tracked by its own FMA column

Check yourself

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