Honeywell MKXXII Audio Inhibit Discrete, Landing Gear Discrete, Weight on Wheels WOW Discrete

Models: MKXXII

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Honeywell

MK XXII EGPWS Installation Manual

3.3.13.3 Audio Inhibit Discrete

The Audio Inhibit discrete is an optional input to maintain audio and visual prioritization. When activated, this discrete inhibits all audio (Ground Proximity and Terrain Awareness). Activation of the Audio Inhibit input for more than 60 seconds will result in the “All Modes Inhibit” fault.

The Audio Inhibit discrete input can be connected to any or all of the following (as applicable to the aircraft configuration):

-a separately labeled guarded cockpit switch

For some existing GPWS installations, this discrete may have been tied to the analog Radio Altimeter Receiver-Transmitter Self-Test output. This connection is no longer required but may be left intact for this installation.

Discrete

Audio Inhibit +28

Position / Status

Inhibit = +28V

Not Inhibit = Gnd/Open

Connector Pin

J1-36

Honeywell does not recommend the use of this input for Helicopters.

3.3.13.4 Landing Gear Discrete

Landing Gear discrete is supplied by the Gear (or Gear handle) switch. The active position (+28V or GND) indicates “Gear Down” and should be connected to a contact that will indicate Gear Down when the Gear are lowered.

Discrete

Landing Gear +28

Landing Gear Gnd

Position / Status

Down = +28V

Not Down = Gnd/Open

Down = Gnd

Not Down = +28V /Open

Connector Pin

J1-35

J1-16

For fixed gear or skid equipped aircraft this input is not required.

3.3.13.5 Weight ON Wheels (WOW) Discrete

The Weight on Wheels (WOW) discrete is supplied by the WOW system in the aircraft. Connection can be made to the actual OLEO switch or relay logic later in the aircraft wiring.

For aircraft without WOW indication such as those with fixed gear or skids, this input discrete is not required.

Discrete

WOW +28

WOW Gnd

Position / Status

On Ground = +28V In Air = Gnd/Open

On Ground = Gnd

In Air = +28V /Open

Connector Pin

J1-37

J1-18

CAGE CODE: 97896 SCALE: NONE SIZE: A DWG NO: 060-4314-225

REV: C SHEET 97

Page 97
Image 97
Honeywell MKXXII installation manual Audio Inhibit Discrete, Landing Gear Discrete, Weight on Wheels WOW Discrete