Vertical Beam Sensor (Vbs); Vor Capture (Cap); Vor After Over Station Sensor (Aoss) - Honeywell PRIMUS 1000 Pilot's Manual

PRIMUSr1000 Integrated Avionics System

Vertical Beam Sensor (VBS)

The VBS determines the point of glideslope capture using a number of
inputs. The VBS is armed when the NAV radio is tuned to a LOC
frequency, the LOC receiver is valid, and the LBS is tripped. The VBS
trips as a function of VS, TAS, and glideslope deviation. The VBS trips
when deviation is less than 150 mV and a capture sensor is satisfied.
The capture sensor combines airspeed, rate of change of beam
deviation, and acceleration to determine the best capture point. In the
event the aircraft is paralleling the beam (i.e., no beam closure rate),
the VBS trips at a vertical deviation less than 36 µA. This resets the
previously selected pitch mode and changes aircraft attitude to capture
the glideslope beam.

VOR Capture (CAP)

VOR CAP occurs when the following conditions are satisfied:
The VOR mode has been armed plus 3 seconds of elapsed time (ET)
D
The LBS has tripped.
D
VOR Over Station Sensor (OSS)
The OSS is used to detect the erratic radio signal encountered in the
area above the VOR transmitter. When these radio signals reach a
certain level of deviation, they are no longer useful and the OSS
eliminates them from the control signal.
OSS is computed when, with DME valid, a 30_VOR station zone of
confusion is assumed and calculated, using barometric altitude for
VOR navigation. During VOR approach, the formula computes the
zone with radio altitude.
NOTE: If the radio altimeter is invalid, the computer assumes a 2500
foot altitude for VOR approach computations.
With DME invalid:
VOR track has occurred plus 3 seconds of elapsed time
D
Lateral deviation is greater than 75 mV and the rate of deviation is
D
greater than 8 mV per second and the DME is not present.

VOR After Over Station Sensor (AOSS)

During the period when neither the OSS control function, nor the NOC
control function are notified, the system operates in AOSS. AOSS
permits large bank angles so that prior to track controlling the aircraft,
a larger course correction can be made.
System Limits
7-4
A28--1146--112--00