Honeywell MK VI - Manual (Page 103)

Honeywell
MK VI MK VIII EGPWS Installation Design Guide
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3.15 Category 1 3 – Input / Output Discrete Type Select
Category 13 defines the input and output discretes not defined as part of any of the other Categories.
Appendix E Table 5.3.13 defines the Input/Output discretes options and identifies the first MK VI/VIII EGPWS
version in which the option was available (see the Effectivity entry).
3.15.1 Input Discr etes
The discrete inputs are defined in Appendix E Section 6.6 Additional information for the discretes is provided
below.
Note: When there are two discrete pin choices for the same pin function in Appendix E Table 5.3.13-x, use only
the one that matches the aircraft wiring either +28V or Ground.
3.15.1.1 Glideslope Inhibit Discrete
The Glideslope Inhibit discrete is used for Backcourse Inhibit of Mode 5 Glideslope. Either the +28V (J1-38)
discrete or the ground (J1-19) discrete may be used. If Backcourse is not available these discretes may be left
open.
Discrete Position / Status Connector Pin
Glideslope Inhibit +28 Inhibit = +28V
Not Inhibit = Gnd/Open
J1-38
Glideslope Inhibit Gnd Inhibit = Gnd
Not Inhibit = +28V /Open
J1-19
3.15.1.2 Landing Fla ps Discrete
Landing Flap discrete is supplied by a Flap or Flap handle switch. The active position (+28V or GND) indicates
“Not Landing Flaps” (or Flaps Up) and should be connected to a contact that will indicate Flaps Up until the
Flaps are lowered to landing position prior to landing. The Landing Flap discrete active position can be reversed
by the ‘Flap Reversal Option’ of Appendix E Table 5.3.7 as shown in the following tables. Flap Override for MK
VIII EGPWS can be done by a guarded (or illuminated) cockpit switch that simulates the Flap Down condition.
+28 VDC Landing Flap discrete active position:
Flap Reversal (Category 7)
Flap Discrete (J1-37)
False True
Landing Flap discrete = +28V Flaps Up Flaps Down
Landing Flap Discrete = Open (or GND) Flaps Down Flaps
Cat. 13 ID 254/255 only *
Flap Override = OVRD +28V +28V
Flap Override = NORM Open Open
* Category 13 ID 254/255 must use this method for Flap Override.