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4-0 General

The Autoflight system provides lateral and vertical control via the Autopilot (AP) or guidance by the Flight Director (FD).
Lateral modes:
Heading Select
Nav Mode
VOR/LOC Mode
Land Mode
Vertical Modes:
Altitude Hold
Level Change
Vertical Speed
Approach
The Autothrottle System (ATS) provides automatic control of the throttles.
The different ATS modes are:
Speed
Mach
N1 Hold
The Thrust Rating Computer (TRC) computes the N1 limits according to TAT and the plane's altitude.