FMGC

Also from: Flight Management Guidance and Envelope Computer; FMGEC

There are 2 FMGCs, each divided into 3 parts:

Flight Management (FM)
Flight Guidance (FG)
Flight Envelope (FE)
FIDS [Fault Isolation and Detection System] (FMGC 1)

The 4th part, FIDS, is for maintenance purposes only.

The FMGCs exchange data through a cross-talk bus and are synchronised, with one of the FMGCs designated the master. Generally each FMGC has access to information from onside sources. There are reset switches on the overhead panel for each FMGC, and for each FM individually.

Each FMGC has its own database that is updated every 28 days. If the databases are not the same, the FMGS operates in independent operation.

Flight management

Controls:

navigation
flight planning
performance optimisation
predictions
display management

Flight guidance

Provides:

FD [Flight Director] commands
AP [Autopilot] commands
A/THR commands

Flight envelope

Provides:

flight envelope calculations
maneuvering speed calculations
GW [Gross Weight] /CG [Centre of Gravity] computations
windshear and aft CG warnings
monitoring of FM and FG parameters

Failures

FMGC Reset

Can be caused due to a temporary software interruption. If a managed mode is engaged, the AP may trip off because of the reset. The FD will revert to HDG V/S modes. The FM reverts temporarily from dual mode to single mode. If the reset is not successful, a manual reset may sometimes be done using the reset buttons on the overhead panel.

Double FMGC Failure

Blanks both MCDU screens and displays FM1 and FM2 lights, and the message MAP NOT AVAIL on the ND.

Categories: Airbus A330 | Auto Flight | Automatic Flight System