Technical data

Product Specification
HIF-2121/R5 CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 965-1176-601 REV: D SHEET 109
6.10.2.2 Current Faults
Faults and failures in the system are divided into two main categories, internal faults and external faults. These main two
categories are used to distinguish faults for different processing requirements. (For example recording faults into fault
history.) Faults are further broken down in to sub-categories; discrete faults, ARINC 429 bus activity faults, analog input wire
monitoring faults, ARINC 429 signal faults, analog signal faults and configuration module faults. Refer to the Installation
Design Guide for specific system status messages for current faults.
Some fault examples are as follows:
FAULT EXAMPLE REASON
ARINC 429 Bus Fault GPS BUS INACTIVE No expected input labels received for more than
4 seconds
ARINC 429 Signal Fault ILS BUS GLIDESLOPE FAULT FW The SSM of the input data indicates
Failure/Warning
Note: Only the RS232 present status will report
the ‘FW” part of the fault.
ARINC 429 Signal Fault ILS BUS GLIDESLOPE FAULT UPD The input label is not meeting the required
update rate, or is not present.
Note: Only the RS232 present status will report
the ‘UPD” part of the fault.
Analog Signal Fault RADIO ALTIMETER WIRING FAULT Open wire monitoring has detected no
connection.
Discrete Input Faults FLAP SWITCH FAULT Indicates Landing Flaps for > 60 seconds with an
airspeed > 250 knots for GA Fast or 210 knots
for GA Slow, or indicates not landing flaps for
more than 2 seconds with “Too Low Flaps”
message below 100 feet.
GEAR SWITCH FAULT Indicates Landing Gear for > 60 seconds with an
airspeed > 250 knots, or indicates not landing
gear for more than 2 seconds with “Too Low
Gear” message below 100 feet.
GLIDESLOPE CANCEL INVALID Discrete selected for > 15 seconds.
RANGE UNREASONABLE No valid range provided for > 5 seconds.
SELF-TEST INVALID Discrete selected for > 60 seconds.
MOMENTARY TERRAIN
SELECT 1 (or 2) INVALID
Selected for > 15 seconds.
6.10.2.2.1 Internal Faults
Internal faults are those faults that originate within the EGPWC. These faults are indicated via the EGPWS front panel
“Computer Fail” LED, self-test and the RS-232 and ARINC 429 interfaces.
6.10.2.2.2 External Faults
External faults are those faults that originate from sources outside the EGPWC. The following faults are categorized as
external faults: ARINC 429 bus activity faults, analog input wire monitoring faults, ARINC 429 signal faults, and analog
signal faults. These faults are indicated via the EGPWS front panel “External Fault” LED, self-test and the RS-232 interface.
6.10.2.3 System Monitors
The system monitor provides three discrete outputs indicating the status (whether a particular function is valid or not).
Detected data failures and internal computer failures will activate these outputs. The analog versions of these outputs are
designed to remain on when power is off, or the EGPWC experiences catastrophic failure. Front panel LEDs are also
provided as described in section 6.10.4.
6.10.2.3.1 GPWS Monitor
The EGPWS monitor is activated by failures that affect the GPWS functions. Both analog and digital versions of the monitor
are provided. The configured discrete output is biased on with loss of system power.