INSTRUMENT LANDING SYSTEM / MARKER BEACONS
• VERTICAL DEVIATION DISPLAY
The vertical deviation scale is displayed on the right side of the ADI
when a localizer is tuned and identified. In this instance, the scale is
the glideslope for the selected Instrument Landing System (ILS)
approach. When tuned to an identified ILS frequency, the pilot can use
the display controller to select glideslope information for display on the
vertical deviation scale from either the on-side or cross-side ILS. The
scale consists of a rectangle with two dots above and below it where
each dot represents a graduation of 1.5° above or below glideslope on
an ILS approach.
The display of the glideslope deviation pointer and scale are not
displayed when the localizer back course (BC LOC) is active or armed
on the flight director. The glideslope deviation pointer or bug is a
truncated cyan triangle that represents the position of the aircraft on
the ILS approach in relation to the glideslope.
The rectangular box on the horizon line represents the position of the
aircraft. The glideslope bug shows the pilot where the glideslope is in
relation to the helicopter. When the bug is above the box on the
display, the helicopter is below glideslope and viceversa. Using the
position of the bug in relation to the dots, the pilot can estimate the
number of degrees the aircraft is above or below the glideslope. When
the bug is immediately adjacent to the box, the aircraft is on glideslope.
In helicopters equipped with a flight director, the bug is magenta when
the flight director is coupled.
• ILS MISCOMPARE
When a localizer miscompare is detected, the system alerts the pilot by
displaying the LOC miscompare annunciator. The loss of valid
information from either NAV receiver does not display the LOC
miscompare annunciator.
When a glideslope miscompare is detected, the system alerts the pilot
by displayng the GS miscompare annunciator. The loss of
valid information from either NAV receiver does not display the GS
miscompare annunciator.
• MARKER BEACON ANNUNCIATORS
OUTER (
O
), MIDDLE (
M
) and INNER (
I
),
marker beacon annunciators are displayed on the ADI and are
controlled by the selected NAV receiver (VOR/LOC).
When the selected navigation source is not from the VOR/LOC, the
marker beacon generates from the on-side NAV receiver.