3.8.7 SELF-TEST DISCRETE 
Type: Supplied by momentary actuated cockpit self-test switch Signal Status: Self-Test or Normal Fault monitoring: Activation of this input continuously for more than 60 seconds will result in the "Self-Test Invalid” 
fault which will cause a GPWS INOP indication. Note: This input is used to start and stop the Level 6 Self-Test, there is no audio output for this discrete in Level 6.
3.8.8     DISCRETES 
To activate Steep Approach, both of the Steep Approach discretes must be selected. Discrete #1 should be enabled if Steep Approach is to be used, and can be permanently enabled.  Discrete #2 should be selected in flight when starting a steep approach, it should not be permanently selected. On ground Self-Test is inhibited if Steep Approach is active. 
3.8.8.1 STEEP APPROACH DISCRETE #1 (MK V AND MK VII ONLY) 
Type: Steep Approach Enabled 
Signal Status: Steep Approach Enabled or Disabled 
Level 6 Audio readout Enabled => “Steep Approach Enabled” Steep Approach Discrete #1 Disabled => “Steep Approach Disabled”
3.8.8.2 STEEP APPROACH DISCRETE #2 
Type: Steep Approach Selected Signal Status: Steep Approach Selected or Not Selected 
Level 6 Audio readout Selected => “Steep Approach Selected” Steep Approach Discrete #2 
Not Selected =>  “Steep Approach Not Selected”
3.8.9 GND ILS TUNED DISCRETE 
Type: Supplied by ILS/VOR Mode Selector. Signal Status: ILS tuned or VOR tuned 
Level 6  Audio readout  
GND ILS Tuned Discrete #1  ILS Tuned => ILS Not Tuned =>  “ILS 1 Tuned” “ILS 1 Not Tuned”  
GND ILS Tuned Discrete #2  ILS Tuned => ILS Not Tuned =>  “ILS 2 Tuned” “ILS 2 Not Tuned” 
3.8.10 +28V ILS TUNED DISCRETE 
Type: Supplied by ILS/VOR Mode Selector. Signal Status: ILS tuned or VOR tuned 
Level 6  Audio readout  
+28 V ILS Tuned Discrete #1  ILS Tuned => ILS Not Tuned =>  “28V ILS 1 Tuned” “28V ILS 1 Not Tuned”  
+28 V ILS Tuned Discrete #2  ILS Tuned => ILS Not Tuned =>  “28V ILS 2 Tuned” “28V ILS 2 Not Tuned” 
3.8.11 GLIDESLOPE VALIDITY DISCRETES 
Two Glideslope Validity Discretes may be used by EGPWS, one for each possible ARINC 547 Glideslope Receiver 
input. 
Type: Validity from ARINC 547 Glideslope receiver. 
Signal Status: Valid or Invalid
Level 6  Audio readout  
Glideslope Validity Discrete #1  Valid => Invalid =>  “Glideslope 1 Valid” “Glideslope 1 Invalid”  
Glideslope Validity Discrete #2  Valid => Invalid =>  “Glideslope 2 Valid” “Glideslope 2 Invalid” 
 
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