Weather Radar Transceiver(s)
Captain and First Officer Terrain Display Relays
Dedicated discretes are sent to the Weather Radar to inhibit lower priority Predictive Windshear alerts. The captain's and first officer's terrain display discretes are used to energize the relays after manual or automatic selection of the terrain display.An analog audio output is provided to the MAWEA. The MAWEA amplifies and outputs the audio signal to the flight deck warning speakers.
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MAINTENANCE MANUAL
B. BITE and Test
(1)
CMC Initiated Tests
(a) The ground proximity warning system can be tested by the CMC in two ways, either a confidence test or a ground test. The confidence test is intended to allow the pilots to initiate a complete system operational test. The ground test is intended to allow maintenance personnel to initiate a complete system operational test. The tests are initiated from the CDU and can only be conducted while the airplane is on the ground. If a fault is detected a FAIL message will appear on the CDU adjacent to the GPWC line select key.
(2)
Fault Monitoring
(a)
The EGPWS BITE function detects and records internal EGPWS failures. The EGPWS BITE function also detects and records failures with the systems that interface with the EGPWS.
(b)
The EGPWS provides the following EICAS advisory messages:
1) GND PROX SYS
The GND PROX SYS message indicates that the EGPWS is reporting an internal or interfacing system fault that affects Modes 1-5. The GND PROX SYS message may also indicate failure of the Terrain Clearance Floor and Terrain Awareness Alerting and Display functions. GND PROX SYS will be displayed for the following reasons:
a) There is an internal failure of the EGPWC b) There is a bus failure of a system that provides data to the EGPWS c) There is not a valid combination of EGPWC program pins.
d) There is a failure of the Terrain Clearance Floor or Terrain Awareness Alerting and Display functions. 2) TERR POS
The TERR POS message indicates inaccurate or unavailable horizontal position input data to the EGPWC.
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3) TERR OVRD
The TERR OVRD message indicates the terrain override switch is in the terrain override position.
4) AIRPLANES WITH IDS SOFTWARE GE-016, RR-016 , PW-017, AND SUBSEQUENT; WINDSHEAR SYS
The WINDSHEAR SYS message indicates that either Predictive Windshear (PWS) or the EGPWS is reporting an internal or interfacing system fault that makes part of the windshear detection and annunciation feature inoperative.
5) AIRPLANES WITH IDS SOFTWARE -015 AND PW-016;
>WINDSHEAR SYS
The >WINDSHEAR SYS message indicates that either Predictive Windshear (PWS) or the EGPWS is reporting an internal or interfacing system fault that makes part of the windshear detection and annunciation feature inoperative.
6) >ALT CALLOUTS
The >ALT CALLOUTS message indicates that the EGPWS is reporting a system fault that makes the Mode 6 altitude callout feature inoperative.
(c) The EGPWS provides the following EICAS status messages:
1) GND PROX SYS
The GND PROX SYS message indicates a failure in the basic GPWS system (Modes 1-5).
2) TERR SYS
The TERR SYS message indicates that the EGPWS is reporting an internal or interfacing system fault that affects the TAAD and TCF modes.
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