MESSAGES
82005-PG-D
SANDEL SN3500 EHSI PILOT’S GUIDE
PAGE
10-3
Message Description
COPY
MEM
This message appears when [MEM]
button is pushed and held. After this
COPY MEM is performed, both memories
will show the display settings in effect
when the COPY MEM was executed.
EXT SW SET TO GPS This message appears when pressing the
“NAV” button on the SN3500 when it is
slaved to an external GPS/NAV
switch/annunciator panel. Instead of the
SN3500 NAV switch use the external
GPS/NAV switch.
EXT SW SET TO NAV This message appears when NAV button
pressed while in slave mode and
selection is NAV.
FCS FDBCK ERR
In some installations the SN3500 Lateral
and Vertical outputs drive the autopilot
directly (See your AFMS). These outputs
are measured and compared to the
expected outputs and the “FCSFDBCK
ERR”
will appear if there is a miscompare
for more than 10 seconds. If this
message appears, it may indicate that the
autopilot may not be accurately flying the
lateral and/or vertical deviation showing
on the course deviation indicators due to
an internal failure in the SN3500 or a
wiring short circuit in the aircraft.
Immediately monitor the lateral and
vertical deviation indicators, and disable
the autopilot (and flight director) NAV or
APPR mode for the duration of the flight if
the autopilot is not tracking as expected.
HDG mode may still be used in this
circumstance if verified to be working.
MESSAGES
82005-PG-D
SANDEL SN3500 EHSI PILOT’S GUIDE
PAGE
10-4
Message Description
FGATE EXCIT LOST
Fluxgate excitation has failed. Check the
gyro circuit breaker. Note 2
FGATE XYZ LOST
Fluxgate XYZ signal voltage too low or
not received.
GYRO INVALID
Gyro valid flag asserted. Check the gyro
circuit breaker. Note 2
GYRO XYZ LOST
Gyro XYZ (synchro) signal voltage too
low or not received.
GYRO/FG CFG BAD
The Heading hardware configuration is
incorrect. Either a stepper gyro has been
configured without a fluxgate (heading
steppers must be slaved), or an ARINC-
429 heading source has been configured
with a fluxgate (ARINC-429 heading
inputs may not be slaved).
MAP CRC INVALID
Indicates that the upload of the map
database to the unit was not completed
successfully or the file was corrupted.
Repeat the upload procedure. Contact
Sandel technical support if the messages
persist. All other functions of the SN3500
continue to operate normally when the
map has failed.
