FLAGS AND ABNORMAL CONDITIONS
82005-PG-D
SANDEL SN3500 EHSI PILOT’S GUIDE
PAGE
9-1
CHAPTER 9 FLAGS AND ABNORMAL CONDITIONS
The SN3500 detects abnormal conditions such as flagged
navigation receivers and failed directional gyro or fluxgate. It also
monitors its own internal temperature and provides warnings for
over temperature or loss of cooling conditions.
In some cases, the flagged displayed will be accompanied with a
failed equipment list message. This message can be accessed by
holding down the menu button until the message display shows.
The list will show both current and prior messages (if applicable).
To show just the current messages, exit the message page by
pressing the menu button and reenter by holding down the menu
button.
Figure 9-1 Messages
FLAG OR
CONDITION
DISPLAY DESCRIPTION
Large red “X” through the CDI
scale, and the deviation bar is
not displayed. Numeric
information display shows “---
“.
NAV flag
Note: CDI pointer will be visible under the red “X” for
two minutes after power-up to allow testing for certain
GPS receivers.
FLAGS AND ABNORMAL CONDITIONS
82005-PG-D
SANDEL SN3500 EHSI PILOT’S GUIDE
PAGE
9-2
GS (glideslope)
flag
Large red “X” through
glideslope scale (VDI),
glideslope pointer is not
displayed.
GS flag,
backcourse
Large yellow "X" through
glideslope scale (VDI) to show
that you are on backcourse
approach.
Directional gyro
failure
Compass rose color changes
from white to amber. The
inner course and vertical
deviation indicators are
removed. Heading data is
obtained from fluxgate alone if
connected to SN3500.
Because fluxgate signals are
averaged over time, heading
response will lag the aircraft
significantly.
Fluxgate failure
Compass rose color changes
from white to amber and the
compass heading is redlined.
The inner course and vertical
deviation indicators are
removed. The display can be
used to determine relative
headings for turns, but the
magnetic compass should be
used to determine absolute
heading.
