distress frequencies of 121.5 and 243.0 MHz. The
radiated signal is modulated with an audio swept tone.
b. ELT Controls and Functions.
(1) ON / ARM / OFF Switch (Located on
(a) ON Turns set on, initiating
emergency signal transmission.
(b) ARM Establishes a readiness
state to start automatic emergency signal transmission
when forces on the ELT exceed a preset threshold.
(c) OFF Turns set off.
(2) Remote RESET / AUTO / XMIT Switch.
(a) AUTO Arms the set to operate
automatically upon impact.
(b) XMIT Turns set on.
(c) RESET In the event the ELT is
accidentally triggered, pushing the switch to the reset
position five times within 3 seconds will deactivate the
transmitter and return the set to the armed (AUTO)
Section III. NAVIGATION
The navigation equipment group provides the
pilot and copilot with the instrumentation required to
establish and maintain an accurate flight course and
position, and to make an approach on instruments in
Instrument Meteorological Conditions (IMC). The
navigation configuration includes equipment for
determining attitude, position, destination, range,
bearing, heading, and groundspeed.
3C-13. FLIGHT DISPLAY SYSTEM (FDS-255).
a. System Overview. The Flight Display
System (FDS-255), is a replacement for existing
electromechanical Attitude Direction Indicator (ADI)
The top and bottom displays are physically
identical. The top display is configured as an
Electronic Attitude Direction Indicator (EADI) and the
bottom display is configured as an Electronic
Horizontal Situation Indicator (EHSI).
The MFD provides all of the internal diagnostics,
data processing, and hardware configuration to
provide the following display modes.
(1) HSI. Full compass rose (360
) or HSI
ARC which includes course needles, a bearing needle,
heading bug, etc.
(2) MAP. A centered 360
MAP or an
expanded compass rose segment (80
). Both of these
modes include the current set of waypoints and course
(3) ADI. Provides aircraft attitude pitch and
roll, lateral deviation, and vertical deviation.
(4) Primary Flight Display (PFD). ADI and
HSI combined on one display as a reversionary mode
upon failure of a display.
(5) Diagnostics. Provides Multi Functional
Display (MFD) status pages.
b. External Aircraft Controls.
Reversionary switches are external push button
switches allowing the operator to place the EADI
information on the bottom display. The pilots switch is
located on the lower left portion of the dash panel
under the Turn and Slip Indicator. The copilots switch
is located on the lower right portion of the dash panel
under the Vertical Speed Indicator. The switch has
two positions, normal and reversionary. In the normal
position the top display is an EADI and the bottom
display is an EHSI. In the reversionary position the top
display blanks and the bottom display becomes a
(2) OBS / LEG Switch. The OBS / LEG
switch places the FMS 2 KLN 90B in either LEG or
OBS mode. The OBS / LEG switch is located on the
top center portion of the dash panel to the right of the
altitude select panel. While in LEG mode the KLN 90B
continuously updates the desired course in order to fly
a great circle route between the FROM and TO
waypoints. If the leg selection is made and FMS 2 is
selected as the primary navigation source, the digital
course label displays DTK. While in OBS mode the
pilots MFD control panel updates the course and
sends the manually selected course to the KLN 90B.
If the OBS selection is made and FMS 2 KLN 90B is
selected as the course source, the digital course label
displays CRS and reflects the pilots control panel