With AP1 and AP2 engaged for a dual channel approach, which FMGC is the master?

With AP1 and AP2 engaged for a dual channel approach, which FMGC is the master?

• A. FMGC 2
• B. Either FMGC can be master
• C. Neither FMGC is master
• D. FMGC 1

Answer: (D)

In a dual-channel setup with AP1 and AP2 engaged, one FMGC serves as the authoritative source for all navigation and guidance data. FMGC 1 is the master, computing the flight plan, navigation data, and performance calculations, and then delivering the guidance signals to both autopilots. FMGC 2 acts as a backup that mirrors data and cross-checks, ready to take over if needed. This arrangement keeps the guidance coherent and ensures continuity of control if a fault occurs.

In a dual-channel setup with AP1 and AP2 engaged, one FMGC serves as the authoritative source for all navigation and guidance data. FMGC 1 is the master, computing the flight plan, navigation data, and performance calculations, and then delivering the guidance signals to both autopilots. FMGC 2 acts as a backup that mirrors data and cross-checks, ready to take over if needed. This arrangement keeps the guidance coherent and ensures continuity of control if a fault occurs.