Overview
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Replace with overview of AFDS architecture, FMC integration, and autoland capability.
The Autopilot Flight Director System (AFDS) consists of three autopilots (L, C, R), three Flight Control Computers, and dual Flight Management Computers (FMC). The 747-400 is certified for CAT IIIB autoland with all three autopilots engaged.
Architecture
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<AutoFlightSchematic /> once built — a block diagram of FCC ↔ FMC ↔ MCP ↔ servos.Components
| Autopilots | 3 — L, C, R (independent) |
| Flight Control Computers | 3 — FCC L, C, R |
| Flight Management Computers | 2 — FMC L, R |
| Mode Control Panel | Glareshield-mounted, dual independent CDUs |
| Autoland Capability | CAT IIIB (3 A/P engaged, LAND 3 annunciation) |
| Autothrottle | Dual channel, integrated with FMC |
AFDS Modes
Lateral
HDG SEL, HDG HOLD, LNAV, LOC, ROLLOUT, ATT
Vertical
ALT HOLD, ALT, V/S, FLCH, VNAV PTH, VNAV SPD, G/S, FLARE
Autothrottle
THR REF, THR, IDLE, HOLD, SPD
Failures & Abnormals
CAUTION — Autoland Status
Verify LAND 3 annunciation before continuing approach in CAT IIIB conditions. LAND 2 = fail-passive only; CAT IIIA limit applies.
Limits
- A/P min engage altitude (takeoff): 250 ft AGL
- A/P engage in approach (manually): per approach plate
- LAND 3 required below: alert height (typ 100 ft RA)
Notes / Personal
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User notes.