Beechcraft C-12C Operator And Technical Reference Manual page 272

TM 1-1510-218-10
3A-25. DISTANCE
SYSTEM (DME-40).
a. Description. The DME system measures the
slant range, line-of-sight, distance from the aircraft to a
ground station and displays a continuous distance
readout in nautical miles. The system also displays
aircraft groundspeed in knots or time-to-station in
minutes. The groundspeed and time-to-station are
accurate only if the aircraft is flying directly toward the
ground station at a sufficient distance that the slant
range and ground range are nearly equal. The DME
system is protected by a 2-ampere circuit breaker,
placarded DME, on the overhead circuit breaker panel.
b. Controls and Functions, DME Control
Panel. Refer to Figure 3A-17.
(1) DME SEL Switch. Controls operation of
the system.
(a) STBY. Places system in standby.
(b) VOR-1.
using frequency controls for VOR-1.
(c) HOLD. System will remain tuned to
previous channel if the VOR is tuned to a new
frequency.
(d) VOR-2.
using frequency controls for VOR-2.
(2) VOL Control. Controls volume.
1. DME SEL Switch
2. VOL Control
Figure 3A-17. DME Control Panel
3A-30
MEASURING EQUIPMENT
Allows channel selection
Allows channel selection
c. Controls/Indicators and Functions, DME
Indicator. Refer to Figure 3A-18.
1. TEST Push Button
2. DME MILES Indicator
3. Control Switch
4. Knots / Minutes Display
5. DIM Control
Figure 3A-18. DME Indicator
(1) TEST Push Button. Initiates self-test of
DME system. When pressed, upper display indicates
0.0 or 0.1 and lower display indicates dashes if control
switch is in MIN position or 888 when in the KTS
position.
(2) DME MILES Indicator. Digital display of
slant-range distance from aircraft to ground station in
nautical miles.
(3) Control Switch. Controls operation of the
DME system.
(a) OFF. Turns system off.
(b) MIN.
minutes for display on bottom readout.
(c) KTS. Selects aircraft groundspeed in
knots for display on bottom readout.
Selects time-to-station in