When the above conditions have been satisied, the autopilot will maintain the desired bank angle. With the autopilot
engaged, bank angles up to 35 degrees can be established using the turn knob. If touch control steering (TCS) was
used to initiate the roll, bank angles up to 35 degrees can be maintained and TCS ENG will be annunciated on the
(3) Heading select mode. The heading select mode is used to intercept and maintain magnetic heading.
The mode is selected with the HDG button-indicator on the light director mode selector panel (Fig. 3-9). A
magenta HDG annunciator on the PFD, annunciates heading mode selection. The heading marker is set on the
heading dial of the PFD by means of the instrument remote controller (pedestal extension, Fig. 2-19). When
operating in the heading mode the light control computer provides inputs to the pitch and roll command cue on
the PFD to command a turn to the heading selected by the heading marker located on the PFD compass rose.
Heading mode signal gain is a function of airspeed. Bank angle limit is 25 degrees in the heading select mode.
Heading select mode is cancelled by:
Capture of any other lateral steering mode
Selecting go-around mode
Selecting standby mode
FMS 1/2 reversionary selection
NAV, ATT, or HDG reversionary selections
(4) VOR (NAV ) mode. The VOR mode provides for automatic intercept, capture, and tracking of selected
VOR radial, using the selected navigation source displayed on the PFD. The navigation source displayed on the
PFD is a function of the VOR/localizer (V/L) pushbutton selector switch located on the display controller (Fig. 2-22).
Prior to engaging the VOR (NAV ) mode, perform the following:
(a) VOR navigation receiver control panel -- Set desired VOR frequency.
(b) V/L pushbutton selector switch (display controller) -- Depress to select VOR1 or VOR2.
(c) Course pointer (PFD) -- Set desired course on heading dial.
(d) Heading marker (PFD) -- Set desired intercept heading for selected course.
With the aircraft outside the normal capture range of the VOR signal (typically, course deviation indicator on PFD
off course by more than 2 dots), engage the NAV button-indicator on the light director mode selector. HDG button-
indicator on the light director mode selector panel will illuminate ON , and the NAV button-indicator will annunciate
ARM . HDG (magenta) and VOR ARM (white) will also be annunciated on the PFD. The light control computer is
now armed to capture the VOR signal, and is generating a roll command to ly the heading select mode. When
reaching the lateral beam sensor trip point, the system will automatically drop the heading select mode and will
switch to the VOR capture phase. The PFD will display the following indications:
VOR annunciator (white) will extinguish.
HDG annunciator (green) will extinguish.
NAV (green) will be annunciated and will be enclosed in a white box for 5 seconds to indicate the capture
The heading pushbutton button-indicator on the autopilot/light director mode selector will extinguish and the NAV
pushbutton button-indicator will switch from ARM to CAP . The light control computer will generate the proper roll
command to capture and track the selected VOR radial. Course select error signal is established by the heading
selected by the course pointer on the PFD. This signal represents the difference between the actual aircraft heading
and the desired course. The course error signal is then sent from the symbol generator to the light control computer.
The radio deviation signal is routed from the navigation receiver to the symbol generator and light control computer.
The signal is lateral gain programmed in the light control computer. The lateral gain programming is performed as a
function of DME distance to the station (if available), true airspeed, and barometric altitude. This gain programming
adjusts for the aircraft going toward or away from the VOR station.