Lateral Beam Sensor (Lbs) - Honeywell PRIMUS 1000 Pilot's Manual

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PRIMUS 1000 Integrated Avionics System

LATERAL BEAM SENSOR (LBS)

When intercepting the VOR, localizer, or back course beam, the LBS
is tripped as a function of beam deviation, course error, true airspeed,
and DME (if DME is available and not on HOLD). In the localizer mode,
the course error is compared with the beam deviation signal to
determine the LBS trip point.
When the LBS trips, the flight director commands a turn away from the
desired VOR radial or runway to decrease closure rate and capture the
beam. If the intercept angle to the beam center is very shallow, the LBS
does not trip until the aircraft is near beam center. For this reason, an
override on the LBS occurs when the beam deviation reaches the
specified minimum. When this occurs, the aircraft turns into the beam
to increase closure rate.
LOCALIZER CAPTURE
Localizer capture applies both to front course and back course
approaches. Capture occurs when the following conditions are met:
D
Localizer and back course armed plus 1 second
D
Either of the following occurs:
— Lateral beam sensor has tripped, or
— Beam deviation is less than 0.75°.
LOCALIZER GAIN PROGRAMMING (LOC II)
LOC II applies both to front course (localizer, ILS) and back course
approaches. It affects the final phase of the approach. LOC II starts
programming at 1200 feet radio altitude either when glideslope is
captured or glideslope data is not valid.
System Limits
5-2
A28–1146–134
REV 1 Jan/03