7th Bomb Wing · B-1B Lancer

Autopilot Reference

Every autopilot mode on the B-1B glareshield — what it does, when to use it, and what kills it. The foundation of every instrument approach.

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Glareshield layout
AP
ALT
HDG
NAV
ATH
APR

AP must be ON before any sub-mode functions. Sub-mode buttons are lit green when active, amber when armed.

Mode reference
AP — Master Autopilot
Prerequisite for all other modes
  • Must be engaged before any sub-mode works
  • Press the AP ON button on the glareshield
  • Disengage: press AP again, or press the sidestick disconnect
  • Always disengage before manual maneuvering
HDG — Heading Hold
Lateral — holds magnetic heading
  • Holds the current magnetic heading when engaged
  • Change target: rotate the HDG SEL knob
  • Drops out automatically when APR captures the localizer
  • Do not re-engage HDG after APR captures — will override the LOC track
NAV — Navigation Hold
Lateral — tracks navigation source
  • Tracks whatever navigation source is selected on the PFD softkey
  • PFD = GPS → follows GPS flight plan route
  • PFD = NAV1 → tracks VOR1 radial set in CRS knob
  • Used for RNAV and VOR approaches — not for ILS
ALT — Altitude Hold
Vertical — holds current altitude
  • Holds the altitude at the moment of engagement
  • Re-engage after leveling off at a new altitude to capture that altitude
  • Changes to G/S annunciation when ILS glideslope is captured
  • Must engage manually at MDA on RNAV/VOR approaches — not automatic
ATH — Autothrottle
Speed — holds current indicated airspeed
  • Holds the airspeed at engagement
  • Set target speed with the SPD SEL knob before engagement
  • Disengages automatically below 2,500 ft AGL
  • At KDYS (1,790 ft MSL field elev): ATH cuts out at ~4,290 ft MSL
  • Take over throttle immediately at ATH cutoff — hold VREF manually
This is the most dangerous limitation. Students who ignore ATH cutoff will lose speed silently and become dangerously slow in the flare.
APR — Approach Mode
ILS only — arms LOC then G/S capture
  • Arms the ILS localizer capture — button turns amber
  • LOC captured → button turns green, HDG drops out
  • G/S captured → ALT changes to G/S annunciation
  • Requires: ILS frequency in FMS NAV1, PFD softkey = ILS, NAV MODE = NAV
  • Never use APR for RNAV or VOR approaches
Mode combinations by approach type
ApproachLateral modePFD softkeyNAV MODEVerticalAPR?
ILSAPRILSNAVAuto G/S✓ Yes
RNAV / GPSNAV HOLDGPSGPSManual V/S → ALT✗ No
VOR / DMENAV HOLDNAV1NAVManual V/S → ALT✗ No
Cruise / EnrouteNAV HOLD or HDGGPSGPSALT HOLD✗ No
Selector knobs
KnobSetsUsed with
HDG SELTarget magnetic headingHDG HOLD mode
CRS SELCourse / inbound radialAPR mode (ILS) · NAV HOLD (VOR)
ALT SELTarget altitude for preselectALT HOLD preselect
V/S SELVertical speed (ft/min)Manual descent on RNAV/VOR approaches
SPD SELTarget indicated airspeedATH mode