Honeywell SPZ-8000 Pilot's Manual page 182

As the aircraft continues toward localizer beam center, the computer
enters the LOC CAP 2 submode. With the aircraft almost lined up on
localizer beam center, the computer automatically changes to the LOC
TRACK 1 and the LOC TRACK 2 submodes. The LOC CAP 2 and LOC
TRACK submodes apply tighter control law programming on the
localizer signal fly a tighter flightpath along the localizer beam. There
is no annunciation that these submodes have engaged.
NOTE: When flying a localizer intercept, the optimum intercept angle
is 45. If the intercept angle is greater than 45, course cut
limiting may occur as previously described in the VOR mode
of operation.
When the course select pointer is set on the EHSI using the CRS knob
on the instrument remote controllers, the course select error signal is
established. This signal represents the difference between actual
aircraft heading and the aircraft course.
The navigation receiver sends the radio deviation signal to the symbol
generator. From the symbol generator, the radio deviation signal goes
to the flight guidance controller, where the signal is lateral gain
programmed.
Lateral gain programming is required to adjust the gain of localizer
signal due to the aircraft approaching the localizer transmitter and beam
convergence caused by the directional qualities of the localizer
transmitter. The lateral gain programmer is controlled by a distance
from transmitter estimator, as shown in Figure 8--17.
Localizer (NAV) Mode Track Profile
If both radio altitude and glideslope deviation are valid, then distance
is calculated using radio altitude and glideslope deviation data. If only
radio altitude is valid, distance is first estimated for capture. Then,
when the LOC TRACK 2 mode engages, it is assumed that an approach
is being made without glideslope, and distance is calculated based on
radio altitude only.
A28--1146--055
REV 2
SPZ--8000 Digital Integrated Flight Control System
Figure 8--17
Modes of Operation
8-21