OPERATOR’S MANUAL
CMA-9000 FLIGHT MANAGEMENT SYSTEM
NAVIGATION IN DEAD RECKONING (DR) MODE
CAUTION: IFR operation in dead reckoning mode may not be permitted in certain classes of airspace.
When reversion to DR mode occurs (due to unavailability of all other navigation modes), the FMS must rely
solely on heading, true airspeed and the last computed value of wind, for navigation. This results in a position
accuracy which degrades continuously during prolonged intervals of DR operation. The rate at which accuracy
degrades depends on the quality of the source of the heading and speed inputs. The FMS may therefore only
maintain its normal accuracy if DR operation does not exceed three to five minutes duration (at typical speeds; it
will be longer at lower speeds).
Navigation accuracy during prolonged DR operation may be improved by manual updating of present position
and/or the actual track and ground speed and/or the wind speed and wind direction based on external
information. This is particularly necessary during periods of changing winds, since the FMS providing navigation
data assumes constant wind during DR operation. In an installation where digital True Airspeed (TAS) is not
provided, the FMS assumes constant ground speed during DR operation, therefore the latter must be updated
manually at regular intervals.
Manual update of the FMS track and ground speed is accomplished as follows:
1. Display the PROGRESS 1/4 page by pressing [PROG].
2. Enter the track angle in True (T)/Magnetic (
o
)and ground speed in knots into the scratchpad, e.g. 281/228.
3. Move the track angle and ground speed to the TK/GS field by pressing LSK 3R.
NOTE: Track angle and ground speed will automatically be updated as soon as the FMS resumes normal
navigation operation.
PROGRESS 1/4
280
T
DTGNM ETE
ARRIE 35.2 00+20.2<
280
o
TOU 88.3 00+32.2
TRUE WIND TK/GS
>020
T
/ 45KT 281
T
/228KT
TKE/XTK
R000
T
/L0.00NM
RNP/ANP
1.00/0.05
NM
NAV MODE
<DR
Page 17-4
August 17, 2010
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