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Section 4 Reversionary Modes
1
st
Ed Nov 2018
IDU-450 EFIS Software Version 8.0H (Rotorcraft)
4-7
NOTE:
At any time, view HFOM on the FAULTS page to see the system-reported
accuracy.
Figure 4-3: FAULTS Page on MFD
1)
DR
(Dead Reckoning)
a) If a GPS position cannot be calculated, a dead reckoning solution
is provided with a timer
. This solution is calculated
from heading and TAS derived from the AHRS and ADC.
2)
Loss of Vertical Navigation
Figure 4-4: Loss of Vertical Navigation (VLON)
If the navigation equipment is no longer adequate to conduct or
continue the LNAV/VNAV approach, “VLON” appears within one
second of the onset of any of the following conditions:
a) The absence of power;
b) Equipment malfunction or failure;